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Measurement of upper extremity performance as a function of the seating system

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Title:
Measurement of upper extremity performance as a function of the seating system a comparison on people with multiple sclerosis and a comparison group
Creator:
Castro, Francisco
Publication Date:
Language:
English
Physical Description:
186 leaves : illustrations ; 28 cm

Subjects

Subjects / Keywords:
Multiple sclerosis ( lcsh )
Wheelchairs -- Design and construction ( lcsh )
Electric wheelchairs -- Design and construction ( lcsh )
People with disabilities -- Orientation and mobility ( lcsh )
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bibliography ( marcgt )
theses ( marcgt )
non-fiction ( marcgt )

Notes

Bibliography:
Includes bibliographical references (leaves 182-186).
Statement of Responsibility:
by Francisco Castro.

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University of Florida
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All applicable rights reserved by the source institution and holding location.
Resource Identifier:
54514608 ( OCLC )
ocm54514608
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LD1190.E55 2003m C37 ( lcc )

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Full Text
MEASUREMENT OF UPPER EXTREMITY PERFORMANCE AS A FUNCTION
OF THE SEATING SYSTEM: A COMPARISON ON PEOPLE WITH MULTIPLE
SCLEROSIS AND A COMPARISON GROUP
by
Francisco Castro
B.S. Pontificia Universidad Catolica del Peru, 1998
A thesis submitted to the
University of Colorado at Denver
in partial fulfillment
of the requirements for the degree of
Master of Science
Mechanical Engineering


2003 by Francisco Castro
All rights reserved


This thesis for the Master of Science
Degree by
Francisco Castro
has been approved
by
Ronald A. L. Rorrer
Dan D. Scott
r/zo/oi
Date


Castro, Francisco (M.S., Mechanical Engineering)
Measurement of Upper Extremity Performance as a Function of the Seating System: a
Comparison on People with Multiple Sclerosis and a Comparison Group.
Thesis directed by Assistant Professor Ronald A.L. Rorrer
ABSTRACT
Multiple Sclerosis (MS) is a neurological disease that causes fatigue and
severe motor and sensory problems. Because of these symptoms, there is a decrease
in mobility, as well as a reduced quality of life. In order to reduce those effects,
subject with MS are usually prescribed with powered mobility aids. There are
currently two different groups of powered mobility aids or seating systems; powered
customized wheelchairs and motorized non-customized scooters. The election of the
seating system depends on the level of the disease; the more severely disabled are
prescribed with a customized wheelchair.
It was hypothesized, based on the observation of medical personnel, that
subjects with MS will have better postural support for their pelvis and trunk and will
therefore have better upper extremity performance in a customized seating system
(wheelchair) than in a non-customized seating system (scooter).
Ten subjects with MS were tested in both a wheelchair and scooter on a 10-
degree tilted surface. Additionally, ten healthy subjects were tested as a comparison
IV


group. A sequence of tasks while sitting was implemented in order to evaluate their
performance. These tasks involved lateral and forward reaches, a continuous
movement around two pegs following an elliptical path, and can stacking.
A measurement motion analysis and pressure mat systems were utilized to
calculate biomechanical parameters as angles, path length, and distance variations.
Statistical analyses were performed to compare the results of the customized and non-
customized seating system.
For subjects with MS, results showed no overall differences on using the two
seating systems. Some measurements on the body-seat interface showed greater
values in the wheelchair, even though a subjective study was also performed on this
group and its results showed that they felt more comfortable in the wheelchair.
Subjects from the comparison group did not show any differences on using the two
seating systems, and their performance was greater than the performance of the
subjects with MS.
The study faced some limitations. Both seating systems were tested over a 4-
hour period, so chronic changes may not be identifiable. As a pilot test, it may not be
sensitive enough to measure the differences.
This abstract accurately represents the contents of the candidates thesis. I
recommend its publication.
Signed
Ronald A.L. Rorrer
v


DEDICATION
To:
All members of my family


ACKNOWLEDGMENTS
I am grateful to my advisor, Ronald A. L. Rorrer, Ph.D., for his guidance,
support and patience during the duration of the study.
It is a pleasure to thank Donna J. Blake, M.D. and Dan D. Scott, M.D., who
not only brought the idea for the project and the funding to make this research
possible but also made valuable comments on this study.
I am particularly indebted to Patrice M. Kennedy, MPT. and Thomas Hearty,
DPT., for their invaluable help and support during the data collection.
I must especially thank Shirley Fitzgerald, Ph.D. for her comments and help
with the statistical analyses of the project.
I also acknowledge Heather C. Lahaie, Theodore A. Zeiger and Edward G.
Westhead for their invaluable support and technical help.
My thanks to the Human Performance Laboratory, Rehabilitation Medicine -
Physical Therapy Program, University of Colorado Health Sciences Center where the
motion analysis was performed.
Finally, I wish to express my gratitude to the Pittsburgh Veterans Health
Administration, Rehabilitation Research & Development, Centers of Excellence
Program, which provided the funding for the study.


TABLE OF CONTENTS
Figures......................................................................xv
Tables.....................................................................xxi
Nomenclature...............................................................xxiv
Chapter
1. Introduction..............................................................1
1.1 Multiple Sclerosis.......................................................1
1.2 Impact of MS on Daily Llife Activities: Need of Mobility Aids............2
1.3 Seating Systems: Customized and Non-Customized...........................3
1.4 Current Methods.........................................................5
1.4.1 Posture................................................................6
1.4.2 Fatigue................................................................9
1.4.2.1 Qualitative Approach................................................10
1.4.2.2 Quantitative Studies................................................14
2. Hypothesis...............................................................17
3. Methodology..............................................................20
3.1 Population: Comparison Group and Subjects with MS.......................21
3.1.1 Comparison Group......................................................21
3.1.2 Subj ects with MS.....................................................21
vm


3.1.2.1 Consent Protocol
,23
3.1.2.2 Test Preparation....................................................23
3.2 Test Equipment......................................................23
3.2.1 Measurement Motion Analysis System....................................24
3.2.2 Force Sensitive Applications (FSA) System.............................29
3.2.3 Synchronizing Device..................................................30
3.2.4 Tilted Surfaces.......................................................32
3.2.5 Peg Holders...........................................................34
3.2.6 Other Tools...........................................................35
3.3 Test Description........................................................35
3.3.1 Previous Set-Up..................................................... 35
3.3.2 Sequence of Tasks................................................... 36
3.3.2.1 Initial Lateral and Forward Reaching Task...........................36
3.3.2.2 Elliptical Path Task................................................38
3.3.2.3 Can Stacking Task................................................. 40
3.3.2.4 Final Lateral and Forward Reaching Task.............................40
3.3.3 Time Sequence.........................................................41
3.3.4 Randomization and Resting Procedure...................................42
3.4 Test Conditions.......................................................43
4. Data Analysis............................................................44
4.1 Coordinate Systems......................................................44
ix


4.1.1 Laboratory Coordinate System............................................44
4.1.2 Seating Coordinate System..............................................45
4.1.3 Auxiliary Coordinate System............................................50
4.2 Reduced Marker Set.......................................................51
4.3 Vector and Matrix Descriptions...........................................53
4.3.1 Vector Notation.........................................................53
4.3.2 Matrix Operators.......................................................53
4.3.2.1 Translation...........................................................53
4.3.2.2 Rotation..............................................................54
4.3.2.3 Translation and Rotation..............................................54
4.4 Calculations.............................................................55
4.4.1 Trunk Excursion........................................................ 55
4.4.1.1 Flexion/Extension Trunk Angle.........................................57
4.4.1.2 Lateral Flexion/Extension Trunk Angle............................... 58
4.4.1.3 Trunk Length..........................................................59
4.4.2 Wrist Trajectory........................................................59
4.4.2.1 Path Length...........................................................60
4.4.2.2 Determination of Cycles during the Elliptical Path Task...............62
4.4.2.3 Reaching Ratio for the Lateral and Forward Reaching Task..............63
4.4.2.3.1 Lateral Reaching Ratio..............................................63
4.4.2.3.2 Forward Reaching Ratio..............................................65
x


4.4.2.4 Vertical Distance from Acromium to Wrist...........................66
4.4.3 Posture............................................................ 67
4.4.3.1 Trunk-Leg Angle....................................................68
4.4.3.2 Knee Angle.........................................................68
4.4.3.3 Leg Deviation Angle.............................................. 68
4.4.4 Center of Pressure (COP).............................................69
4.4.4.1 COP Displacement...................................................71
4.4.4.2 Root Mean Square (RMS) of the COP Displacement.....................71
4.5 Statistical Analysis..................................................73
4.5.1 Comparison of Seating Systems........................................73
4.5.2 Comparison of Groups.................................................75
4.5.3 Order Performed Comparison.........:.................................76
4.5.4 Correlation Analysis.................................................76
5. Results.................................................................78
5.1 Result Examples........................................................78
5.1.1 Trunk Excursion Results..............................................78
5.1.2 Wrist Trajectory Results.............................................82
5.1.3 Posture Results.................................................... 90
5.1.4 Center of Pressure Results...........................................95
5.2 Data Summary..........................................................97
5.2.1 Seating System Comparison Results....................................97
xi


5.2.1.1 Lateral and Forward Reaching Task Results..........................97
5.2.1.2 Elliptical Path Task Results.......................................104
5.2.1.3 Can Stacking Task Results..........................................108
5.2.2 Order Performed Comparison Results...................................108
5.2.3 Correlation Test Results.............................................109
5.2.4 Group Ranking...................................................... 109
6. Discussion, Conclusions and Recommendations.............................113
6.1 Discussion.............................................................113
6.2 Conclusions...........................................................116
6.3 Recommendations.......................................................117
Appendix
A. Colorado Multiple Institutional Review Board...........................120
B. Veterans Affairs Research Consent Form.................................122
C. Medical/Demographic Questionnaire......................................127
D. Physical Exam and Anthropometric Measurements..........................132
E. Procedures.............................................................136
E. 1 Subject preparation prior to testing.............................136
E.2 Instructions given to subjects during testing......................137
E.2.1 Test 1: Lateral and Forward Reaching Task........................137
E.2.2 Test 2: Elliptical Path Task.....................................137
E.2.3 Test 3: Can Stacking Task........................................137
xii


E.3 Data Collection Procedure
138
E.3.1 Prior to testing..................................................138
E.3.2 Prior to each Task................................................138
E.3.3 During the Task...................................................139
E.3.4 Subsequent to the Task............................................139
E.4 Digitization Process using the Peak Motus System....................139
F. Triggering Device..................................................... 140
G. Marker Locations........................................................142
G.l Acromium Marker.....................................................143
G.2 Elbow Markers.......................................................143
G.3 Wrist Markers.......................................................144
G.4 Greater Trochanter Markers...................................... 145
G.5 Knee Markers........................................................145
G.6 Ankle Markers.......................................................146
H. Tilted Surfaces.........................................................147
I. Peg Holder..............................................................152
J. Individual Data for the Seating System Comparison.......................159
J.l Results from Subjects with MS.......................................159
J.1.1 Lateral and Forward Reaching Task.................................159
J.l.2 Elliptical Path Task..............................................162
J.l.3 Can Stacking Task.................................................164
xm


J.2 Results from the Comparison Group...................................165
J.2.1 Lateral and Forward Reaching Task..................................165
J.2.2 Elliptical Path Task...............................................168
J. 2.3 Can Stacking Task.................................................169
K. Individual Data for the Order Performed Comparison......................170
K. 1 Results from Subjects with MS......................................170
K.1.1 Lateral and Forward Reaching Task..................................170
K.1.2 Elliptical Path Task...............................................174
K.l.3 Can Stacking Task..................................................175
K.2 Results from the Comparison Group ...................................176
K.2.1 Lateral and Forward Reaching Task..................................176
K.2.2 Elliptical Path Task............................................. 180
K.2.3 Can Stacking Task..................................................181
References...................................................................182
xiv


FIGURES
Figure
2.1 Hypothesized Performance Variation During Testing....................19
3.1 Marker Set...........................................................24
3.2 Laboratory Set Up for a Right-Handed Person..........................26
3.3 Seventeen-Marker Calibration Frame...................................27
3.4 Laboratory Coordinate System Frame...................................28
3.5 Video Processing.....................................................29
3.6 Pressure Distribution on the FSA Mat.................................30
3.7 Measurement Systems..................................................31
3.8 Tilted Surfaces......................................................33
3.9 Seating System Location on the Tilted Surface........................33
3.10 Peg Holder.........................................................34
3.11 Frontal View of the Lateral Reaching Task for a
Right-Handed Individual.............................................37
3.12 Lateral View of the Frontal Reaching Task for a
Right-Handed Individual ............................................38
3.13 Peg Locations for a Right-Handed Person............................39
xv


3.14 Can Stacking Test Arrangement.........................................40
3.15 Time Sequence (minutes)...............................................42
4.1 Laboratory Frame Reference.............................................45
4.2 Coordinate System Rotations............................................46
4.3 Seating Coordinate System..............................................47
4.4 Vectors P, Q, and R attached to the Seating System.....................48
4.5 Auxiliary Coordinate System............................................50
4.6 Marker Set Locations and Calculated Joint Centers.................... 52
4.7 Locations Involved on Defining the Trunk...............................55
4.8 Trunk Vector Expressed in the Seating Coordinate System................57
4.9 Flexion/Extension Trunk Angle..........................................58
4.10 Lateral Flexion/Extension Trunk Angle.:............................. 59
4.11 Distance between to Consecutive Locations.............................61
4.12 Determination of the Duration of the Cycles...........................62
4.13 Lateral Reaching Distance for a Right-Handed Subject..................64
4.14 Forward Reaching Distance for a Right-Handed Subject..................65
4.15 Vertical Distance from Acromium to Wrist..............................66
4.16 Posture Angles........................................................67
4.17 Leg Deviation Angles..................................................69
4.18 Resultant Force and Center of Pressure Location on the FSA Mat........70
4.19 Root Mean Square of the COP Displacement..............................72
xvi


4.20 Tests Performed for the Seating System Comparison......................74
4.21 Tests Performed for the Group Comparison...............................75
4.22 Tests Performed for the Order Performed Comparison....................76
5.1 Trunk Excursion Angles during Lateral and Forward Reaching Task
for a Subject with MS in the Wheelchair.................................79
5.2 Trunk Length Variation during Lateral and Forward Reaching Task
for a Subject with MS in the Wheelchair.................................80
5.3 Trunk Excursion Angles during the Elliptical Path Task for a
Subject with MS in the Wheelchair.......................................81
5.4 Trunk Length Variation during the Elliptical Path Task for a
Subject with MS in the Wheelchair.......................................81
5.5 Trajectory of the Wrist during the Forward and Lateral Reaching
Task for a Subject with MS in the Wheelchair............................83
5.6 Trajectory of the Wrist during the Forward and Lateral Reaching
Task for a Subject with MS in the Scooter...............................83
5.7 Trajectory of the Wrist during the Forward and Lateral Reaching
Task for a Comparison Group Subject in the Wheelchair...................84
5.8 Trajectory of the Wrist during the Forward and Lateral Reaching
Task for a Comparison Group Subject in the Scooter......................84
5.9 Right Wrist Trajectory dining the Elliptical Path Task.for a
Subject with MS in the Wheelchair.......................................85
xvii


5.10 Cycle during the Elliptical Path Task...................................86
5.11 Right Wrist Trajectory during the Elliptical Path Task.for a
Subject with MS in the Scooter..........................................87
5.12 Right Wrist Trajectory during the Elliptical Path Task.for a Comparison
Group Subject in the Wheelchair.........................................87
5.13 Right Wrist Trajectory during the Elliptical Path Task.for a Comparison
Group Subject in the Scooter............................................88
5.14 Vertical Distance from the Wrist to the Acromium during the Lateral and
Forward Reaching Task for a Subject with MS in the Wheelchair...........89
5.15 Vertical Distance from the Wrist to the Acromium during the
Elliptical Path Task for a Subject with MS in the Wheelchair............89
5.16 Arm Length Variation during the Lateral and Forward Reaching
Task for a Subject with MS in the Wheelchair............................90
5.17 Posture Angle Results during the Lateral and Forward Reaching
Task for a Subject with MS in the Wheelchair............................91
5.18 Posture Angle Results during the Elliptical Path Task for a Subject with
MS in the Wheelchair....................................................91
5.19 Leg Deviation Angles during the Lateral and Forward Reaching
Task for a Subject with MS in the Wheelchair............................92
5.20 Leg Deviation Angles during the Lateral and Forward Reaching
Task for a Subject with MS in the Scooter...............................93
xviii


5.21 Leg Deviation Angle during the Elliptical Path Reaching
Task for a Subject with MS in the Wheelchair...........................94
5.22 Leg Deviation Angle during the Elliptical Path Reaching
Task for a Subject with MS in the Scooter..............................94
5.23 Data provided by the FSA System for a Given Frame......................95
5.24 COP Displacement during the Lateral and Forward Reaching Task for a
Subject with MS in the Wheelchair......................................96
5.25 COP Displacement during the Elliptical Path Task for a Subject with
MS in the Wheelchair....................................................96
5.26 Can Stacking Completion Time Results...................................109
5.27 Path Length per Cycle Results..........................................110
5.28 Path Length per Cycle Variation.....:..................................111
5.29 Path Length per Cycle per Arm Length Results...........................112
F. l Wiring of the Triggering Device.........................................140
G. 1 Anatomical Landmarks...................................................142
G.2 Anterior (Frontal) View of the Right Acromium Marker.....................143
G.3 Anterior (Frontal) View of the Right Elbow Markers.......................144
G.4 Anterior (Frontal) View of the Right Wrist Markers.......................144
G.5 Anterior (Frontal) View of die Right Greater Trochanter and
Right Knee Markers.......................................................145
G.6 Anterior (Frontal) View of the Right Ankle Marker........................146
xix


H.l Main Wooden Ramp.......................................................148
H.2 Main Wooden Ramp. Side View, Section A-A...............................149
H.3 Auxiliary Wooden Ramp..................................................150
H. 4 Auxiliary Wooden Ramp. Side and Bottom View...........................151
I. 1 Peg Holder. Lateral View.............................................153
1.2 Peg Holder. Frontal View...............................................154
1.3 Peg Holder. Detail A...................................................155
1.4 Peg Holder. Detail B...................................................156
1.5 Peg Holder. View from A-A..............................................157
1.6 Peg Holder. Detail C and Section B-B...................................158
xx


TABLES
Table
5.1 Lateral and Forward Reaching Task Results for Subjects with MS......99
5.2 Lateral and Forward Reaching Task Results: Seating System Comparison
Performed on Subjects with MS.......................................100
5.3. Lateral and Forward Reaching Task Results for the Comparison Group.101
5.4. Lateral and Forward Reaching Task Results: Seating System
Comparison Performed on the Comparison Group........................102
5.5 Comparison of Means p-value between Groups for the Lateral and Forward
Reaching T ask......................................................103
5.6 Elliptical Path Task Results: Seating System Comparison Performed on
Subjects with MS................................................... 105
5.7.Elliptical Path Task Results: Seating System Comparison Performed on the
Comparison Group....................................................106
5.8 Comparison of Means p-value for the Elliptical Path Test............107
5.9 Can Stacking Tasks Results..........................................108
J.l Lateral and Forward Reaching Task Results from Subjects with MS.
Seating System Comparison...........................................159
xxi


J.2 Elliptical Path Task Results from Subjects with MS. Seating System
Comparison...........................................................162
J.3 Can Stacking Task Results from Subjects with MS. Seating
System Comparison....................................................164
J.4 Lateral and Forward Reaching Task Results from the Comparison Group.
Seating System Comparison............................................165
J.5 Elliptical Path Task Results from the Comparison Group. Seating
System Comparison....................................................168
J. 6 Can Stacking Task Results from the Comparison Group.
Seating System Comparison............................................169
K. 1 Lateral and Forward Reaching Task Results from Subjects with MS.
Order Performed Comparison......................................... 170
K.2 Elliptical Path Task Results from Subjects with MS. Order
Performed Comparison.................................................174
K.3 Can Stacking Task Results from Subjects with MS. Order
Performed Comparison............................................... 175
K.4 Lateral and Forward Reaching Task Results from the Comparison Group.
Order Performed Comparison...........................................176
K.5 Elliptical Path Task Results from the Comparison Group. Order
Performed Comparison.................................................180
xxii


K.6 Can Stacking Task Results from the Comparison Group. Order
Performed Comparison
xxm


NOMENCLATURE
A: Auxiliary Coordinate System.
A,B: Frames.
a,b,c,m: Scalars.
or. Flexion Extension Trunk Angle.
/?: Lateral Flexion Extension Trunk Angle.
d: Trunk Length.
dAw- Vertical Distance from Acromium to Wrist
COP: Center of Pressure.
DVAMC: Denver Veterans Affairs Medical Center.
EMG: Electromyography.
FIS: Fatigue Impact Scale.
FRD: Frontal Reaching Distance.
FRR: Frontal Reaching Ratio.
Frms- Frontal Root Mean Square.
FSA: Force Sensitive Applications/Force Sensing Array.
AAA
I,J,K: Unit Vectors.
Lo: Distance from the Acromium to the end of the middle finger tip.
L: Laboratory Coordinate System.
L: Path Length.
La: Arm Length.
LRD: Lateral Reaching Distance.
LRR: Lateral Reaching Ratio.
xxiv


Frms' Lateral Root Mean Square.
MS: Multiple Sclerosis.
N: Number of frames.
P, Q, R: Vectors.
p: Pressure on the body-seat interface.
p-value: Probability value of two quantities being different for a specific test.
&. Leg Deviation Angle.
gR: Rotation Matrix of frame B with respect to frame A
RMS: Root Mean Square.
ROM: Range of Motion.
S: Vector defining the location of the seating system makers.
SS: Coordinate System attached to Seating System.
S-VHS: Super VHS (Video Home System).
abT : Description Matrix of frame B with respect to frame A
X, Y, Z: Coordinate System Axis.
x,y,z: Vector Components.
xxv


Introduction
1.1 Multiple Sclerosis
Multiple Sclerosis (MS) is an inflammatory disease of the central nervous
system. This neurological disease involves repeated episodes of inflammation of
nervous tissues in any area of the central nervous system: brain and spinal cord. This
process is caused when immune cells of the own body attack the nervous system. The
inflammation destroys the covering of the nerve cells in that area (myelin sheath),
leaving multiple areas of scar tissue (sclerosis) along the covering of the nerve cells.
This results in slowing or blocking the transmission of nerve impulses in that area,
leading to the symptoms of MS. Because of the variable distribution of demyelination
throughout the central nervous system, people with MS may experience disorders of
balance, coordination, strength, sensation, vision, and muscle tone1.
Symptoms vary because the location and extent of each attack varies. There is
usually a stepwise progression of the disorder, with episodes that last days, weeks, or
months alternating with times of reduced or no symptoms (remission). Recurrence
(relapse) is common although non-stop progression without periods of remission may
also occur.
The prevalence of MS seems to be related to the latitude of residency. In
equatorial areas, the prevalence is less than 1 per 100,000, and in the southern United
1


States and southern Europe it is 6 to 14 per 100,000. The highest prevalence occurs in
Canada, northern Europe and the northern United States and varies from 30 to 80 per
100,0002. There are 250,000 to 350,000 cases in the United States3. The Veterans
Health Administration provides care to approximately 20,000 of these cases.
Estimates place the average direct and indirect health-related costs at $35,000 per
patient with MS per year4.
MS is the third most common cause of disabling illness in individuals between
the ages of 15 and 50. The mean age of onset is 32 years old2. This disease involves
twice as many women as men. However, MS is, on average, more severe in male
subjects.
1.2 Impact of MS on Daily Life Activities:
Need of Mobility Aids
The most common symptoms of MS are fatigue and severe motor and sensory
problems. Because of these symptoms, there is a decrease in mobility, as well as a
reduced quality of life in people with MS. Symptoms can worsen if the patient is
exposed to heat or prolonged physical activity5. To avoid worsening symptoms,
people with MS will often reduce physical activity and recreation.
In order to provide a better quality of life, as well as improved mobility,
mobility aids, such as manual wheelchairs, powered wheelchairs and motorized
scooters, have been prescribed for people with MS. In 1983, about 40% of the MS
population required the use of these mobility aids for community and home mobility6.
2


These mobility aids or seating systems are prescribed for people with MS
based on their level of disability, with the more severely disabled individuals being
provided a customized power wheelchair. Initially a patient may use a manual
wheelchair and then, coincident with progression of the disease, may start using a
powered mobility aid. When a person with MS loses the ability to propel a manual
wheelchair, develops quadriparesis and/or marked fatigability, a powered mobility aid
may be needed7. Once power mobility becomes necessary for the patient, the medical
providers and the patient decide which type of powered seating system is most
appropriate. Most of the people with MS prefer a motorized scooter because they feel
they have more control of their movements and that they look less disabled. However,
use of scooters is controversial in the medical community. This is based on the
observation of patients sitting in the two different motorized seating systems. It is
commonly thought that people with MS using scooters will decrease their physical
activity faster than powered wheelchair users do secondary to increased fatigue from
a non-supportive seating system.
1.3 Seating Systems: Customized and Non-Customized
When wheelchairs are prescribed, specifications such as tilt angle, back angle,
depth, width and kind of cushion, leg and trunk support, headrest, armrest and
footrest position, etc. can be measured and adjusted by a trained clinician in order to
provide a custom fit for each individual. For all these reason a powered wheelchair
can be classified as a customized seating system. On the other hand, when a scooter is
3


issued, a minimum number of variables can be addressed, such as seat height, armrest
position and headrest position. This generic system is made to fit many different body
sizes. Scooters are essentially off-the-shelf mobility aids and can be identified as
non-customized seating systems.
Several studies have shown the importance of seating systems in the life of the
users. A study in an elderly population showed that if a coordinated wheelchair
management approach by trained individuals is not used, it could result in decreased
independence and deterioration of physical condition of the users8. A proper seating
system may increase a persons tolerance to wheelchair usage and improve cardiac
and respiratory function. On the other hand, if the seating system is inappropriate and
results in poor posture, it can cause disk degeneration and low back pain9. Poor
posture can result in spinal deformities, increased spasticity and pain in the neck and
shoulders, increased risk of pressure ulcers and decreased respiratory function10,11.
The purpose of this pilot study is to investigate if body posture in different
seating systems contributes to the development of increased fatigue and reduced
performance in people with MS. This requires measurement of posture, performance,
and fatigue during several tasks to compare results from different seating systems.
Since this study involves people with MS from the Veterans Health
Administration, the results can be applied only to the population used. Vollmer3
found that there are some differences between the population used and the general
population. The percentage of males with MS in the general population is
4


approximately 17%, while in the VA population used for this study; the 85% of the
subjects were male.
1.4 Current Methods
A literature review was performed to determine current methods being used to
evaluate performance, posture and fatigue, the variables being examined in this study
of power mobility aids.
One of the quantities most utilized used to measure performance is the
completion time of a task. Hand function tests, such as the Jebsen Test12 and the Nine
Hole Peg Test13, use task completion times to evaluate subjects. A faster completion
time indicates better performance during these fine motor skill tests.
Reaching distance and range of motion (ROM) have been used to measure
performance in people with Parkinsons disease during reaching tasks performed
while standing14. ROM has been defined as thoracic rotation, lateral trunk flexion,
total rotation, and forward trunk flexion. In Schenkmans study, participants
demonstrated a shorter reaching distance than controls. In the latter group, it was
noted younger individuals have greater reaching distances than older individuals. All
measurements were collected by a three-dimensional motion analysis.
Posture and fatigue are two of the most common variables used to evaluate
performance. Current studies of these variables are presented below.
5


1.4.1 Posture
Posture is defined as "the position or bearing of the body" (Websters Medical
Dictionary) and refers to the overall alignment of the various body parts to each other
when a person is standing in a relaxed stance.
The concept of posture has been studied in several experiments, where it has
been related to the center of pressure (COP) of the body-seat interface. Several
articles15,16 have shown that posture can be measured by locating markers on specific
locations of the subjects body, and analyzing the movements as the experiment was
performed. In order to analyze these movements, different motion analysis systems to
capture the signals have been used.
Kamper16 has performed several studies on the postural stability of wheelchair
users and control subjects exposed to external perturbations. Several markers were
located on the users body in order to analyze posture with a video camera. Those
markers were located over multiple positions, including: greater trochanter, iliac
crest, lateral extent of the tenth rib, axilla, lateral base of the neck, and ear. This set of
markers allowed estimation of rotation of the pelvis, lower torso, upper torso, neck
and head. For this study, rotation was quantified in terms of the change in angle from
the starting position. External perturbations were performed using a platform able to
tilt. The center of pressure (COP) was calculated from a force platform and was
compared to those that were obtained from the video. The platform where the
6


wheelchair was located was able to rotate 30 degrees in either the anterior-posterior
or the lateral plane.
In another study, Harrison studied posture in people with cervical pain and
in a group of controls. Reflective markers were placed on the ear, shoulder, and
lateral malleolus. Marker positions were recorded and horizontal distances and angles
were compared.
Curtis performed a study of wheelchair basketball players to compare the
effects of using wheelchair trunk and lower extremity stabilization on sitting trunk
mobility, and functional reach of wheelchair users. The test was repeated 3 times with
different conditions: without a belt, with a neoprene belt and with webbing tight belt.
In order to capture the motion of the participants, the experiment was performed in a
darkened motion analysis laboratoiy using the Motion Analysis Expert Vision
Flextrak program. The markers were placed on the lateral aspect of the right spine of
the scapula, the right trochanter and the knee joint line. A reflective sphere was also
placed in the center of the wheelchair backrest. The study showed that there are
substantial differences between the functional reach of the wheelchair users and the
able-bodied control group. For subjects with low thoracic paraplegia, the functional
reach was increased when the belts were used.
Maltais15 (1999) proposed anatomical landmarks, as well as wheelchair
landmarks, in order to perform sitting and standing tests on able-bodied subjects
seated in wheelchairs. An articulated mechanical arm (Microscribe 3D, Inmersion
7


Corporation) was used to digitize the landmarks. The anatomical and wheelchair
landmarks digitized, 27 in total, for each subject evaluation are the following: lateral
malleolus (2), condyle of the femur (2), greater trochanter (2), anterior superior iliac
spine (2), iliac crest (2), middle trunk (4 on each side), acromium (2), cervical
vertebrae, xyphoid process, suprasternal notch, rear wheel center (2), and metal road
markers (2). Additionally, the study analyzed the pressure distribution on the seat
cushion using the Force Sensing Array (FSA) provided by Vista Med, Inc. A squared
mat with 225 pressure sensors was used. The purpose of the study was to evaluate the
variability of the mechanical parameters. The study suggested that the method
proposed could be used as an accurate procedure to characterize the posture of
subjects sitting in a wheelchair.
However, using marker based video motion analysis is not the only method
that has been used to measure posture. Bendix et.al.19 used inclinometers to measure
trunk position and compare posture of healthy individuals during upper extremity
tasks. In this experiment the tasks consisted on moving 2 pins from one solitaire game
to another. Authors used a statometric technique, where the angles were measured
while individuals were holding their position.
Potten (1999)20 performed an experiment looking at forward reach in order to
analyze the postural muscle responses in people with spinal cord injuries. The author
measured the COP using a force platform (Biovec 1000, AMTI).
8


All these studies show that reflective markers are commonly used to evaluate
posture, especially when gross body movement is being analyzed. Small movements
make the use of markers difficult due to the large size of the markers. Pressure
distribution and the COP displacement on the seat have also been shown to be
important factors in the analysis of posture.
1.4.2 Fatigue
Measurement of fatigue has been performed in several studies However,
most of those measurements have been qualitative, utilizing questionnaires to
evaluate the level of fatigue. The patients were asked about their ability to perform
daily physical activities or tasks.
Limitations of self-report questionnaires used to quantify fatigue severity can
be confounded by other symptoms of MS. Questionnaires are entirely subjective and
require patients to make difficult retrospective assessments21 (Schwid 2002). In this
study the authors presented the force as a quantitative measure and established the
necessity of defining more rigorous and quantitative measures.
Everyone experiences fatigue at various times. For healthy individuals, a
feeling of fatigue is temporary and is usually related to excessive physical activity, a
sedentary lifestyle, poor nutrition, an increase in work or social responsibilities or
lack of sleep. With the appropriate interventions (rest, sleep, better nutrition, or a
change in stimulation) energy is rapidly restored. Acute fatigue is thought to serve a
protective function, alerting a person to the need for rest. Acute fatigue is, by
9


definition, time limited. But for some people, fatigue is a daily experience that affects
all parts of their lives. Rest may lessen the severity of chronic fatigue, but often it
does not completely relieve it. Patients with chronic illnesses and those undergoing
cancer treatment may need to alter their lifestyles to manage fatigue. Such alterations
may be temporary (until the disease process is under control) or may require
permanent changes in patterns of activity. According to the North American Nursing
Diagnosis Association guidelines, the major defining characteristic of chronic fatigue
is the patient's self-report of a sustained and significant lack of energy. For MS22, the
definition of fatigue is a sense of physical tiredness and lack of energy, distinct from
sadness or weakness.
1.4.2.1 Qualitative Approach
Fatigue is one of the most common and disabling symptoms of Multiple
Sclerosis, regardless of the severity of the disease. Regarding people with MS, Krupp
et al. defined fatigue as a sense of physical tiredness and lack of energy, distinct
from sadness or weakness. Qualitative studies have shown that a great percentage of
people with MS have both physical and mental fatigue during normal daily activities.
Fatigue is present in 78 to 87% of the MS population, according to studies performed
by Vercoulen et al.23, Freal et al.24, Ford et al.25 and Fisk et al.26. All these studies
used questionnaires, to have people with MS scale different parameters.
Krupp22 showed that the percentage of people with MS impacted by fatigue
(87%) is greater than the percentage in healthy people (51%). Fatigue severity was
10


assessed with a visual analog scale (VAS). Patients marked on a line the point that
best described their fatigue. For that study, the author used a 100 mm scale. In 1995,
Krupp27 studied the influence of several medications with a similar linear scale, called
the Fatigue Severity Scale. Freal24 used a questionnaire of 25 questions and found that
78% of the people with MS observed were affected by fatigue. Fisk26 found that
fatigue could be present everyday in 40% of the MS population. In this study, Fisk
noted that the actual ratings of fatigue are not typically included in routine
quantitative evaluations.
Chan28 presented an article summarizing the different tools (scales) used to
measure fatigue performed by different authors:
1. Fatigue Severity Scale22: The Fatigue Severity Scale (FSS) was developed and
validated for the MS population. It was designed to describe the impact of fatigue
on daily function. This scale consists of 9 statements. For each of the statements,
the subject selects from a scale of 1 to 7 to indicate the severity of the fatigue
experienced (1 for no impact to 7 for highest impact). The total score of the FSS
ranges from a low of 9 (fatigue has no impact) to a high of 63 (fatigue has a
severe impact).
2. Fatigue Impact Scale26: The Fatigue Impact Scale (FIS) consists of 40 questions
grouped under the 3 domains of cognitive functioning, physical functioning, and
psychosocial functioning. The subject rates the extent to which fatigue causes
problems, from 0 for no problem to 4 for extreme problems. The total score
11


ranges from a low of 0 (fatigue causes no problem) to a high of 160 (fatigue
causes extreme problems). This scale provides a more comprehensive description
of the areas of function in which fatigue has the most impact. Both the FSS and
the FIS have been used in many clinical trials and outcome studies on the MS
population.
3. Fatigue Descriptive Scale29: The Fatigue Descriptive Scale (FDS) is a scale
developed to evaluate the periodicity, severity, and quality of fatigue caused by
MS. Based on the subject's responses, a score of 0 to 3 is assigned to each of the
different categories associated with heat. The FDS is highly correlated with the
FSS.
4. Modified Fatigue Impact Scale: The Clinical Practice Guidelines on Fatigue30
adopted the Modified Fatigue Impact Scale (MFIS) as the scale of choice for
measuring fatigue in MS. Instead of using the 40 questions in the original Fatigue
Impact Scale (FIS), this shortened version consists of 21 questions, grouped under
the same 3 domains. The rating scale for the MFIS remains the same as the one
described for the FIS.
5. Multiple Sclerosis Quality of Life Inventory31: The Multiple Sclerosis Quality of
Life Inventory (MSQLI) is a tool designed to measure the impact of MS on the
individual's quality of life. It consists of many standardized tools, including the
Mental Health Inventoiy, and the Pain Effects Scale. The MFIS is a component of
this quality of life tool.
12


6. Fatigue Questionnaire and Sleep Questionnaire: The Clinical Practice Guidelines
on Fatigue30 also recommend using the Fatigue Questionnaire and the Sleep
Questionnaire to record the degree of fatigue that an individual experiences in a
one-month time frame. The Fatigue Questionnaire categorizes the quality and
severity of fatigue experienced by the individual, and the Sleep Questionnaire
documents the individual's sleep patterns. Information from both questionnaires
and from the MS Daily Activity Diary can be used to develop appropriate fatigue
management strategies.
Perceived exertion was also a measurement performed to observe the variation
of the subject conditions. The Borg Perceived Exertion Scale32 is used to ask subjects
how their perceived exertion is. This tool uses scale from 6 to 20, 6 being the lightest
case and 20 the hardest case, to rate the perceived exertion.
During the present research a subjective study33 was also performed using the
Borg Perceived Exertion Scale and the Fatigue Impact Scale. Subjects with MS were
asked to rate their level of perceived exertion and fatigue using those scales. The
study consisted of a sequence of tasks performed in a customized and a non-
customized seating system. Subjects completed the scales before and after the
sequence was completed in each seating system. Results from the study showed that
subjects perceived more exertion and were more fatigued when the tasks were
completed in the non-customized seating system (scooter). Most of the subjects
(92%) also reported that they felt more stable and tasks were easier to perform in the
13


customized seating system (wheelchair). However the results could be the indicators
of the familiarity of the subjects with the wheelchair, since 92% of the population
who participated in the study was a current wheelchair user.
1.4.2.2 Quantitative Studies
As Fisk mentioned in his work, all these studies have measured fatigue in a
qualitative way and they do not normally include quantitative evaluations. There are
others studies that have attempted to accomplish the quantitative analysis of fatigue.
Provinciali et al.34 utilized different tests, in order to analyze 6 disability
domains in people with MS: timed 10 meter-walking test, the Nine Hole Peg Test13,
card-sorting test, word fluency test, etc. The involved domains were: motor ability,
cognitive performance, daily live activities, mood, handicap and quality of life. This
study showed that more aspects were needed to evaluate the situation of people with
MS.
Frzovic et al.1 (2000) has studied standing balance in people with MS. The
author performed 3 clinical tests: steady stance, self generated perturbation and
external perturbation. The subjects were able to walk a distance of 14 meters, 3 times,
without walking aids. The number of times the subjects could raise their hands during
a period of 15 seconds was recorded. The test was performed twice in a day (10 a.m.
and 3 p.m.) and only light activities were performed during the interval. The study
concluded that there was no difference. Results showed that although patients
reported feeling more fatigued in the afternoon than in the morning, their physical
14


performance showed little change. There was no difference between MS and control
groups on maintaining balance. However, people with MS performed more poorly
than control subjects on the functional reach task.
The study performed by Vollestand35 (1999) presented several methods to
quantitatively measure human fatigue. He classified the methods into direct and
indirect. In the direct method, he included maximal voluntary force generation of both
upper and lower limbs, power output, tetanic force (independent force of the motor
central drive) and low frequency fatigue. In the indirect one, he considered twitch
interpolation, endurance time and electromyography (EMG). Electromyography
(EMG) is a technique used to test the electrical activity of a skeletal muscle. An EMG
is used to detect disorders that mainly affect the muscles. It is also used to diagnose
muscle problems caused by other diseases, such as nerve dysfunction.
Drory et al.36 performed a surface EMG on the upper and lower limb muscles
on people with and control subjects. The study showed that 80% of the MS patients
had abnormal results for the EMG test. Yokota et al.37 performed a comparison of
control subjects, patients with spinal cord transection and people with MS. They
performed EMG on both the palms and soles. The study showed that the results for
75% of people with MS were abnormal.
Similar studies performed independently by Chen39 and Armstrong40. They
measured the knee muscle functions on control subjects and people with MS, using
the Cyber II isokinetic dynamometer to measure the torque. The results showed that
15


patients with MS, when compared with healthy subjects, exhibited mean torque-
velocity values that were significantly lower and yet had curves similar in shape to
healthy subjects.
Most of the studies measuring fatigue have used qualitative measures, which
are not exact indicators of fatigue due to the subjectivity of the methods and the
confusion with other symptoms. The quantitative methods used are related to forces,
power, and muscle activity, but new measurements are still needed, no test has been
able of separate the causes of fatigue objectively.
16


2. Hypothesis
The hypotheses of the study were based on the observation of medical
personnel on people with MS that use power mobility aids. These observations leaded
to hypothesize that people with MS using non-customized seating systems on scooter
bases would decrease their physical activity faster than using customized seating
system on powered wheelchair bases because the latter ones provided a better basis of
support for the subjects body. As mentioned in section 1.2.4.1 the quantitative
study33 performed on the present study supported this hypothesis.
In order to measure the variation on the physical activity of the subject with
MS on each seating system, a sequence of performance tests were used in the study. It
was hypothesized that the overall performance of the test sequence in a customized
seating system (wheelchair) is better than in a non-customized seating system
(scooter).
Performance was determined by the measures calculated on each task of the
whole test. Since the customized seating system provides better basis of support, the
subjects trunk and functionally dominant arm would be able to move further from
the customized seating system compared to a non-customized seating system with a
worse basis of support.
17


For people with MS group the original specific hypotheses of the study based
on the measurements performed were:
1. Because of the larger motion of the arm in the customized seating system, the
total path length during the repeated upper extremity motion task will be
longer in a custom seating system (wheelchair) compared to a non-customized
seating system (scooter).
2. Due to the larger motion of the trunk in the customized seating system
(wheelchair), there will be greater forward and lateral trunk flexion, measured
as angles, than in a non-customized seating system (scooter).
3. Because of the larger combined movement of the trunk and functionally
dominant arm on the customized seating system, the center of pressure (COP)
trajectory of the body-seat interface will have a higher range of motion in a
customized seating system (wheelchair) compared to a non-customized
system (scooter).
Regarding the comparison group, no differences were hypothesized between
the performances on the two seating systems. It was thought that this group
performance was not affected, as much as the performance of the people with MS
group, by the two seating systems compared in the study. Since the performance of
the people with MS was affected by the seating systems, it was hypothesized to be
less than the performance of the comparison group.
18


Figure 2.1 shows the levels of performance hypothesized corresponding for
each case of group and seating system along the time. The comparison group will
start from a higher level (Pi) compared to the people with MS (P2). No differences
will be found on the comparison group. People with MS performance in the non-
customized seating system will decrease faster (P4) compared to the performance in
the customized seating system (P3).
Performance
Comparison Group
(Either Seating System)
People with MS in Customized
Seating System
People with MS in Non-
Customized Seating System
------ Time
Figure 2.1. Hypothesized Performance Variation During Testing.
19


3. Methodology
The present research was conducted to investigate the influence of seating
systems in people with MS on function. A certificate of approval is shown in
Appendix A. Quantitative assessment of performance using posture and reaching
distance has been accomplished in several studies previously mentioned. However,
the quantitative measurement of fatigue has not been well developed to date. There
continues to be a need for additional, more effective measures.
Ten subjects with MS and ten healthy subjects were included in the study. The
analyses of these two groups were performed in order to observe how the seating
systems interacted with them and if they were differences. Testing was performed on
a 10-degree tilted ramp with the subjects functionally dominant on the high side of
the surface in order to increase the challenge on the individuals. The test consisted on
a sequence of tasks that included lateral and forward reaches, repetitive motion
around to pegs following an elliptical path and, can stacking, a subtest from the
Jebsen Test12. Angles of the test subjects body during the tasks, distances traversed,
and center of pressure (COP) excursions were calculated from the collected data.
The study consisted of the following tasks:
1. A sequence of tasks able to show the difference between the two motorized
seating systems.
20


2. A human body motion marker template, which allowed the calculation of
parameters involved with the range of motion during the chosen tasks.
3. Analysis of the results in order to determine and quantify the differences
between the two motorized seating systems.
4. Analysis of the results in order to determine and quantify the differences
between the comparison group and people with MS.
5. Selection of quantities that would express how users interacted with the
seating systems.
3.1 Population: Comparison Group and Subjects with MS
3.1.1 Comparison Group
Ten able-bodied healthy subjects, five males and five females, were used as
reference for the study. The same manual wheelchair and powered scooter was used
for each subject. Subjects were recruited based on their body size, so they would fit
appropriately into the wheelchair and scooter provided. All participants in this group
were of Caucasian with an average age of 41 years old and a standard deviation of
11.6 years.
3.1.2 Subjects with MS
Subjects were recruited from the Multiple Sclerosis Clinic and Wheelchair
Clinic at the Denver Veterans Affairs Medical Center (DVAMC), Physical Medicine
& Rehabilitation Service. All participants received $50.00 US.
21


In order to accomplish the inclusion criteria, all subjects with MS that
participated in the study were using powered mobility provided by the DVAMC. The
average age of this group was 56.4 years old with a deviation standard of 11.8 years
old. Nine of the ten participants were Caucasian and one was African American.
Individuals had trunk and upper limb mobility and they had a Kurtzke Scale rating
between five and eight. The average value of the scale number was 7.05 0.98. This
group had had MS for 17.111.2 years and they had been using mobility aids for
4.63.7 years.
Eight of the ten subjects with MS included in the study had their own
customized seating system on a powered wheelchair base. They had been measured
and fitted by a seating specialist from the DVAMC in a power wheelchair. For these
subjects, the same scooter with an off-the-shelf seating system was provided.
One subject used a motorized scooter as a primary mobility aid, so a
customized seating system on a power wheelchair base was provided for testing. A
trained physical therapy from the DVAMC went through to the procedure of
measuring and fitting this wheelchair to make it customized to this person.
The remaining subject used both a power wheelchair with a customized
seating system and a scooter, which he owned.
22


3.1.2.1 Consent Protocol
Before preparing the subject for data collection, a consent form and protocols
were reviewed privately with each subject. All participants signed an informed
consent prior to initiating of testing. This consent is included in Appendix B.
3.1.2.2 Test Preparation
Individuals with MS completed a demographic medical questionnaire,
included in Appendix C. This questionnaire was utilized to perform the subjective
study33. Subjects also underwent a modified physical examination including range of
motion measurements and manual muscle testing of the arms as well as
anthropometric measurements before the test. Forms used in these exams are included
in Appendix D.
3.2 Test Equipment
Two main systems were used during the test. A measurement motion analysis
system working at a rate of 60 Hz was utilized to quantify the movement of the
individuals during the test. In addition to that, the pressure distribution at the body-
seat interface was collected using a pressure mat working at 10 Hz. Detailed
procedures for the use of these equipments are included in Appendix E. The data
collections of these two systems were started at the same time by using an electronic
synchronizing trigger. The wiring diagram of this device is shown in Appendix F.
23


3.2.1 Measurement Motion Analysis System
The chosen measurement motion analysis system, manufactured by Peak
Performance Technologies Inc, is based on reflective markers attached to the subject's
bony protuberances in order to minimize the effect of the skin movement. Six digital
cameras, working at 60 Hz, tracked the marker movements, using high definition
video tapes (S-VHS). Nineteen spherical markers with a diameter of 0.054 m were
used for testing; this marker set is shown in Fig. 3.1. Reflective markers were placed
on 16 anatomical landmarks, shown in Appendix G, using double-sided tape. A
trained physical therapist located the markers by palpation.
LLE
LLW
Marker Locations
RAC: Right Acromium
LAC: Left Acromium
RGT: Right Greater Trochanter
LGT: Left Greater Trochanter
RLE: Right Lateral Elbow
RME: Right Medial Elbow
LLE: Left Lateral Elbow
LME: Left Medial Elbow
RLW: Right Lateral Wrist
RMW: Right Medial Wrist
LLW: Left Lateral Wrist
LMW: Left Medial Wrist
RK: Right Knee
LK: Left Knee
RA: Right Ankle
LA: Left Ankle
SI: Axis Right End
S2: Axis Left End
S3: Back of the Seating System
Figure 3.1. Marker Set.
24


The other 3 makers were located on the seating system. Each marker was
covered with reflective painting to make the data collection easier. In addition to the
marker set presented, during the elliptical path task two small markers were located at
the ends of the pegs to identify their locations.
Videos, with the recorded trials, were uploaded into a computer using Peak
Motus software. This software allowed identification of and tracking each marker
on all frames during data collection. This allowed three-dimensional data to be
reconstructed and analyzed. Based on the location of each marker defined by the x, y
and z coordinates, calculations of angles and distances were calculated.
The location and orientation of all cameras were arranged such a way that
each marker could be seen from at least two of the cameras at every moment. Once
the desired positions were defined, cameras were secured with adhesive tape. Figure
3.2 shows the laboratory set-up for a right-handed person.
Cameras were focused on the functionally dominant side: in case of Fig. 3.2,
three cameras were located on the right side, one attached to the ceiling and the two
remaining ones were located on the left side. The space covered by all the cameras is
represented in the figure as the green box.
25


Figure 3.2. Laboratory Set Up for a Right-Handed Person.
At the beginning of the test a calibration procedure was performed to define
the location and orientation of the cameras with respect to the laboratory. This was
completed using two different devices:
1. A 17-marker calibration frame: this was utilized in order to determine the
exact relative position and orientation of each auxiliary camera with respect to
the main camera location. A scheme of this frame is shown in Fig. 3.3.
26


0.038 m
All 17 markers must be seen in each camera. In order to accomplish this, the
frame was moved or rotated around the vertical axis of the tripod supporting
the frame.
2. A 3-marker frame: this device is used to locate the origin and orientation of
the laboratory frame with respect to each camera involved. A scheme is
shown in Fig.3.4.
27


Figure 3.4. Laboratory Coordinate System Frame.
Once all markers were seen in all of the six cameras, the views from those
cameras were recorded for later upload. After this, the calibration devices were
removed from the testing space. The cameras remained at the same position and
orientation during the rest of test.
In order to reconstruct the 3-dimensional movement from 2-dimensional
videos it is necessary to have all these videos synchronized. Since this is practically
impossible to accomplish manually, the measurement motion system used has the
ability to produce a signal, by pressing a button at the beginning of each task, which
was sent to all cameras when the test was being performed. This signal is used to
have all videos aligned. Since all the videos had different lengths, only the interval
covered by all cameras was kept for the analysis. This final version of the videos was
recorded into the computer. Figure 3.5 shows how the video processing is performed.
28


Cut
Aligning
Signal
Cut
Tape 1
Tape 2
Tape 3
Tape 4
Tape 5 [
Tape 6
3.2.2 Force Sensitive Applications (FSA) System
A 16 x 16-inch FSA mat pressure containing 256 one-inch pressure sensors
manufactured by Vista Medical was used to collect information about the pressure
distribution on the body-seat interface. Clinicians typically use mats to measure the
effects of cushions and positions on interface pressures for people limited to a
wheelchair for mobility.
Pressure distribution on the 256-sensor mat was collected at a rate of 10 Hz
during the first 44.7 seconds of testing. All data was recorded into by a data logger
system, and then downloaded into a computer with the FSA software. Figure 2.6
shows the pressure distribution measured by the 256 sensors of a person from the
comparison group.
j
Video Interval Used
Figure 3.5. Video Processing.
29


16 15 14 13 12 11 10
Sensors Included 220
Variation coefficient 97.8%
Standard deviation 4B.4
Average pressure 49.5
Maximum pressure 250
Center of pressure 10.9, 9.5
Figure 3.6. Pressure Distribution on the FSA Mat.
Based on the pressure distribution obtained from the mat, the FSA software
evaluates the location of the center of pressure, the average and maximum pressures,
the standard deviation, and the number of cells sensing pressures different from zero
(active cells).
The pressure mat had the disadvantage of creep. In order to take this into
account, continuous pressure relieves or push-ups were performed every 5 minutes.
3.2.3 Synchronizing Device
In order to have the data from the measurement motion analysis system and
the pressure system synchronized, a trigger device was implemented. Its wiring
diagram is shown in Appendix F. This device allowed sending the same signal to the
30


video controller and to start the pressure data collection on the mat. Figure 3.7 shows
a scheme of how the measurement motion and pressure systems where linked using
the trigger. Only the equipment for camera 1 is shown in this case. Equipments
corresponding to other cameras are similar to camera 1.
31


Initially the FSA computer plug (A) is connected to the collection box in order
to set the FSA system up. FSA is set up at the remote set-up mode. Once this system
is ready, plug A is disconnected and the from the measurement motion system plug
(B) is connected. Right before the task started, the trigger box button was pressed,
starting the collection of pressure data and sending a signal to the video controller.
After completing the task, the plug B is disconnected and plug A is connected to let
the FSA computer download and save all data from the corresponding task.
3.2.4 Tilted Surfaces
In order to increase the challenge during testing, the tasks were performed on
a wooden ramp. This ramp was tilted 10, with the subjects dominant side on the
high side of the ramp. The seating system was parallel to the rise of slope of the ramp.
Seating systems were secured to the main wooden surface using tie lock downs. An
antiskid path underneath these surfaces was used to prevent any displacement.
For the comparison group, the seating systems were placed on the ramp,
locked, and then the subject easily sat down. The subjects with MS were placed in the
desired seating system and they drove onto the ramp using auxiliary ramps. The
auxiliary ramps were located at the front and back of the main ramp. They were
attached to main ramp by screws. These three surfaces are shown in Fig. 3.8. The
specifications of all the ramps are included in Appendix H.
32


Figure 3.8. Tilted Surfaces.
Figure 3.9 shows the tilted surfaces assembled together with a power
wheelchair on top of them. The orientation shown corresponds to a right-handed
person. As mention before, the seating system was aligned with the rise of the slope.
The arrows show the way the seating system was driven in order to get up and down
Figure 3.9. Seating System Location on the Tilted Surface.
33


3.2.5 Peg Holders
For the elliptical path task a pair of peg holders were built. One holder is
shown in Fig. 3.10 and the specifications are included in Appendix I. The location of
the reflective marker was vertically variable since it had to adjust to the size of the
subjects. In order to do that an outside threaded bar was attached to the end of the
horizontal bar.
8
These holders were 8 feet tall and held the markers from above in order to
avoid blocking the markers from the cameras views. A reflective marker was located
34


at the end of each peg in order to locate this position with respect to the subjects
movement
3.2.6 Other Tools
A height-variable table, a stop-watched, and five empty soda cans were
utilized for the can stacking portion of the test. Additionally, a tape measure, a lever,
a goniometer, and a small peg were used too. The lever was used for setting the
markers of the holders at the same level as the subjects dominant side shoulder.
3.3 Test Description
Comparison subjects and subjects with MS performed the same task sequence
on each of the seating systems. The order of placement in the seating system was
randomized for each subject.
3.3.1 Previous Set Up
The measurement motion system was calibrated at the beginning of the test
for each subject. After that the ramps were located and oriented according to the
handedness of the subject.
If comparison subjects were being tested, the seating system on its power base
was secured on the tilted surface; the pressure mat was located on the cushion and
finally the subject was seated. If subjects with MS were tested, the pressure mat was
located on the cushion and the subject was seated in that seating system while on the
flat surface. The subject then drove up on to the tilted surface, where they power base
was secured on the ramp.
35


3.3.2 Sequence of Tasks
The following is the sequence of tasks used in the experiment. Individuals
performed this sequence twice: once sitting in the customized seating system on a
power wheelchair base and once in the off-the-shelf seating system of the scooter.
3.3.2.1 Initial Lateral and Forward Reaching Task
Individuals were asked to perform a forward and lateral reaching using their
functionally dominant hand. Before this task, subjects were asked to rate their fatigue
and perceived exertion using the form included in Appendix C in order to perform the
subjective study33. A set of five maximum reaches was completed. Subjects were
looking at a target placed on the wall at eye level in each direction. They were asked
to remain sitting without using the non-dominant arm to hold on to the seat, placing
their non-dominant hand on their thigh. After each reach they were asked to return to
the original position, touch their thigh and then start another reach cycle. They were
provided a command to start at the beginning of the reaching task and a command to
stop at the end of the five cycles. Consistent instructions were given to each subject.
Figure 3.11 shows a frontal view of a right-handed subject performing a
lateral reaching task having a visual target. The initial and the maximum reaching
positions are shown.
36


Figure 3.12 shows a lateral view of a right-handed subject performing a
frontal reaching task. The initial and the maximum reaching positions are shown. As
well as the lateral reach, there was a visual target located on the wall.
37


Figure 3.12. Lateral View of Frontal Reaching Task for a Right-Handed Individual.
3.3.2.2 Elliptical Path Task
This task consisted on thirty circular motions around a target marker placed at
the subject's arm length directly in front of the functionally dominant hand and
another target at 45 degrees laterally to the functionally dominant side. Motion will be
in a counter clockwise direction for people using the right hand and clockwise for
those left hand functionally dominant. Individuals used their functionally dominant
38


hands to go around the target markers holding a small rod in that hand. The locations
of the markers are shown in Fig. 3.13.
Seating System
Lo: distance from the
acromium to the end of the
middle fingertip
(a) Top View
Figure 3.13. Peg Locations for a Right-Handed Person.
The subjects were provided a command to start at the beginning of the
elliptical path, every five repetitions were counted off and a command to stop at the
end of the thirty cycles was given. Consistent instructions were given to each subject.
39


3.3.2.3 Can Stacking Task
Using a sub-test from the Jebsen Test12, five empty soda cans were placed on
a table in front of the seated subject and the subject was asked to place each of the
cans onto a raised surface on the table. This raised surface was 3.5 inches above the
table surface stacked onto a raised board. The time it took the subject to complete the
can sacking was recorded. Consistent instructions were given to each subject. The
arrangement of the cans with respect to the table is shown in Fig.3.14.
Figure 3.14. Can Stacking Test Arrangement.
3.3.2.4 Final Lateral And Forward Reaching Task
The lateral and forward reaching task was repeated as described in section
3.3.2.1. This task was performed in order to observe differences at the beginning and
the end of the test. At the end of this task, subjects were asked to rate their perceived
exertion and fatigue the same way they did before the initial reaching task.
40


3.3.3 Time Sequence
In order to have standardized the completion time of the test for subjects with
MS, a time sequence was established. Initially subjects were seated for 5 minutes and
then performed a weight-relieving push-up. After waiting for 5 minutes, the lateral
and forward reaching task was performed. Immediately after this task, another
weight-relieving push-up was performed and after another five-minute period a new
weight-relieving push-up was performed. The elliptical path task was performed after
waiting for 5 minutes. Two other weight-relieving push-ups with their respective five-
minute periods were performed before the completing the stacking can task. Two
final weight-relieving push-ups and two five-minute periods were performed before
the final lateral and forward reaching task was completed.
Assuming one minute per each lateral and forward reaching task, two minutes
per elliptical path task, and one minute per the stacking can task, the total test time
per seating system was 45 minutes. Periods between each task allowed testers to get
all systems ready to collect. If for any reason, a system did not work at the beginning
of the task, subjects were asked to stop and they performed a push-up at that moment
and another 5-minute period was waited before redoing the task. The time sequence is
shown in Fig.3.15. The comparison group had only one push-up and one five-minute
period before every single task.
41


Weight-Relieving Push-Up
Lateral and Forward Reaching Task
Elliptical Path Task
Can Stacking Task
3.3.4 Randomization and Resting Procedure
The test sequence was repeated in the customized and the non-customized
seating system in a randomized way. This was accomplished by picking the first
seating system, and the others were chosen alternatively.
42


A 30-minute rest period was given to the subjects between testing in the two
seating systems. Depending on which seating system was tested first the structure of
the resting period was chosen.
If the current or familiar mobility aid used by the patient was tested first,
subjects rested for the next twenty minutes in their own seating system. Ten minutes
prior to the beginning of the test in the non-familiar seating system, subjects were
transferred to this seating system. During this period, subjects performed some
reaching and range of motion movements in order to become familiar with the new
seating system.
If the non-familiar seating system was tested first, reaching and range of
motion movements 10 minutes before starting the test. Subjects were transferred to
the familiar seating system as soon as the test is completed on the non-familiar
seating system. The resting period is then performed on the familiar seating system.
3.4 Test Conditions
For subjects with MS population, the room temperature was kept between 68
and 70F using and air conditioning system. During rest periods the lights from the
cameras were turn off in order to minimize the heat radiation coming from the lights.
43


4. Data Analysis
4.1 Coordinate Systems
In order to perform all the biomechanical calculations different reference
Cartesian coordinate systems were defined. These coordinate systems were based on
the laboratory, the seating systems and the trunk of the subjects.
4.1.1 Laboratory Coordinate System
The 3-marker calibration frame defined this coordinate system. It was located
in front of the 17-marker frame (section 3.2.1) at the floor level during the calibration
process. The orientation of this coordinate system was not the same for all subjects
because of the necessity of rotating the frame in order to have the markers on all of
the cameras views during calibration.
Due to the direction of the Xl and Yl axes, the Zl axis was always pointing
upwards to the ceiling of the laboratory. All data from the human motion analysis
system used this coordinate system as a reference. Figure 4.1 shows the orientation of
the laboratory coordinate system with respect to the 3-marker calibration frame. Axes
Xl and Yl were located at floor level.
44


ZL
Figure 4.1. Laboratory Frame Reference.
4.1.2 Seating Coordinate System
The seating coordinate system was based on the markers located on the
seating system tested: Xss, Yss and Zss, where the subscript SS refers to the seating
system. This coordinate system was attached to the seating system. Figure 4.2 shows
the coordinate system rotations in order to get from the laboratoiy to the seating
system coordinate.
Initially there was a rotation of 0i about the Zl axis to align Yl to the frontal
direction of the seating system (Fig. 4.2a), creating the coordinate system XaYaZa,
where the subscript A stands for auxiliary coordinate system. The value of 0i
depended on each subject. The second rotation of 02 was about the Ya axis, which
allowed Xa to be parallel to the axis of the seating system (Fig. 4.2b). The values for
02 were very close to 10 for all subjects.
45



(a) Rotation around the Zl axis (b) Rotation around the Ya axis
Figure 4.2. Coordinate System Rotations.
Three markers placed on the seating system were used to determine this
coordinate system. In order to facilitate the data collection, two of the markers (Si and
S2) were placed at the two ends of the main axis and the remaining one (S3) was
placed at the back of the seating. Figure 4.3 shows a usual location of the markers on
a seating system. If the seating system were placed on a flat surface, the Z-axes of the
auxiliary and the seating coordinate systems were the same (Fig. 4.3a). However,
since the test was performed on a tilted surface, the orientation of the seating
coordinate system was different (Fig. 4.3b). Even though the Y-axis was the same,
axes Xl and Zl were deviated 10 from their corresponding axes in the auxiliary
coordinate system.
46


(a) On Flat Surface.
(b) On Titled Surface.
Figure 4.3. Seating Coordinate System.
The locations of Si and S2 with respect to the origin of the laboratory
coordinate system were expressed as the vectors S: and S2. The vector that comes
from the left end to the right end of the axis was defined as follows.
P = S,-S2 (4.1)
Using the other marker location, S3, it is possible to define another vector.
47


Q = S,-S,
(4.2)
In addition to these two vectors, another vector was defined as the cross product of
the two previous vectors, which creates the vector R = PxQ (4.3)
Figure 4.4 shows the direction and orientation of these vectors with respect to
the laboratory coordinate system. The vector R is perpendicular to the vectors P and
Q since it is the result of the cross product of them.
Figure 4.4. Vectors P, Q, and R attached to the Seating System.
Even though these three vectors are not perpendicular between them and they
are no unit vectors, they constituted a base since they are non-dependant, so any other
vector can be expressed as a linear combination of them as follows.
V = aR + bP+cQ, where a, b, and c are scalars. (4.4)
_ A
The unit vector Kss can also be expressed as this combination as
48


K'ss ajc P+bKQ+cKR
(4.5)
This expression is truly independent from the coordinate system and from the
orientation that the seating system had. In other words, the scalars ak, bx, and ck will
be independent if the seating system was on a flat or tilted surface. If the seating
system remains on a flat surface the vector Kss will be parallel to the positive
vertical direction, this is:
*=[0 0 1]
(4.6)
From the previous expression it is possible to rewrite in a matrix form:
Kss=aP + bQ+cR=[P Q R
(4.7)
a b =[p q - Px Py H -1 0 o' 1
c Pz 1 N 1
vi rin b = m2l C\ LOT31 mu m32 ml3~ Ml 23 m33 "i r-13 0 = 77z23 Finally the scalars quantities are: 1 m33
a = mu (4.8i)
b-m^ (4.8ii)
c~m33 (4.8iii)
A
In order to assume the vector Kss in the vertical direction it was necessary to
obtain the locations of Si, S2, and S3 when the seating system was on a flat surface.
49


A
This procedure was done at the end of the test. Once the unit vector Kss was
determined, the unit vector parallel to the y-axis, Jss, was obtained.
J
ss
Kss*p
KssxP
(4.9)
AAA
Finally, the unit vector parallel to the x-axis is calculated Iss = Jss xKss (4.10)
The origin of this coordinate system was considered as the right end of the seating
system axis (Si).
4.1.3 Auxiliary Coordinate System
In order to compare the trajectories of the wrist during the forward and lateral
reaching and the elliptical path tasks, the auxiliary coordinate system was used. As
explained in section 4.1.2, this frame was obtained by a rotation about the Z-axis of
the laboratory coordinate seating system (Zl). As shown in Fig. 4.5, the origin of this
system was located at the midpoint of the line that jointed the two greater trochanters
of the subject tested at the beginning of the test.
ZA
50


The unit vectors for this coordinate system were obtained as follows. The z-
axis unit vector was the same as the corresponding to the laboratory.
Ka =jf1=[0 0 l]' (4.11)
The Y-axis unit vector was the same as the corresponding to the seating coordinate
A A
system. JA =JSS (4.12)
Finally, the X-axis was determined by the cross product of the two previous unit
vectors. IA=JAxKA (4.13)
4.2 Reduced Marker Set
The original marker set for this study used 17 markers located on the subjects
body. However, in order to perform the calculations, other locations were needed.
The motion measurement system used had the ability to calculate locations based on
the locations of the markers. For this study, the calculated midpoints of the upper
limbs and trunk segments where considered as joint centers. These joint center
locations were the following:
1. Midpoint of the line that jointed the markers on both acromium markers (right
and left acromiums). This location was denoted as MA.
2. Midpoint of the line that jointed the markers on greater trochanters (right and
left greater trochanter). This location was denoted as MGT.
51


3. Midpoint of the lines that jointed the markers on the medial and lateral side of
the elbows. There were two locations in this case: right elbow (RE) and left
elbow (LE).
4. Midpoint of the lines that jointed the markers on the medial and lateral side of
the wrists. There were two locations in this case: right wrist (RW) and left
wrist (LW).
In order to perform the analysis and calculations the calculated joint centers
and some of the marker locations are needed. Those locations are shown in Fig. 4.6.
Marker locations are shown in black () and joint center locations in white (o).
Locations
LAC: Left Acromium
RAC: Right Acromium
MAC: Mid Acromium
LGT: Left Greater Trochanter
RGT: Right Greater Trochanter
MGT: Greater Trochanter
RE: Right Elbow
LE: Left Elbow
RW: Right Wrist
LW: Left Wrist
RK: Right Knee
LK: Left Knee
RW: Right Ankle
LW: Left Ankle
Figure 4.6. Marker Set Locations () and Calculated Joint Centers (o).
52


4.3 Vector and Matrix Descriptions
In order to express the calculated quantities in terms of the reference
coordinate systems presented before, some techniques commonly used in the robotics
field were used. These techniques involved matrix operations and some modifications
to the original vectors. The purpose of using these formats is to make the equations
more compact and to have more efficient computer programs.
4.3.1 Vector Notation
A vector coming from the origin to a location M expressed in frame A is
expressed as APM. Equation 4.14 shows the corresponding format used for the vector.
APM=[mx my mz\ (4.14)
4.3.2 Matrix Operators
In order to express the same vector with respect to different frames it was
necessary to use an operator that involved the translation and rotation required to get
from one frame to another frame.
4.3.2.1 Translation
If the vector M, expressed in frame A as APM, needed to be expressed in a
frame B, which is parallel to frame A, a vector addition was performed to obtain
X- "PM^PM+^BOrs (4-15)
Where APBOrig was the vector of the origin of the B frame expressed in frame A.
53


4.3.2.2 Rotation
Another case of coordinate system transformation was when the vector M,
expressed in frame A as APM, needed to be expressed in frame B, which had the
same origin as A but different orientation. The vector M expressed in frame B as
bPm was related to APM following APM = BRBPM (4.16)
Where BR is a 3x3 matrix called rotation matrix that describes frame B from frame
A, defined as BR = \AIB AJB
(AJB)x (AKB)x
(AJB)r (AkB\
(AJB)z (AKB)z
(4.17)
quantities AIB, AJB, and AKB are the unit vectors of frame B expressed in frame A.
4.3.2.3 Translation and Rotation
The most general case would be when a translation and a rotation were
present during the transformation. For example if the vector M, expressed as
aPm with respect to frame A, needs to be expressed with respect to frame B, as BPM,
the equation that related those two quantities is: APU-ABTBPU (4.18)
where BT is the description of frame B with respect to B, a 4x4 matrix operator
defined as

bR I Ap r BO rig
0 0 0 ! l J
(4.19)
where B R is rotation matrix that express frame B in frame B and APBOrig is the vector
of the origin of the B frame expressed in frame A.
54


4.4 Calculations
Based on the reduced marker set, various quantities were calculated. These
quantities were focused on the trunk and the subjects functionally dominant side
wrist. The motion measurement analysis provided the x, y, and z coordinates of every
marker with respect to the laboratory coordinate system.
4.4.1 Trunk Excursion
Measurement of trunk excursion was based on the markers located at the
acromiums and at the greater trochanters. The trunk was idealized as the line that
joins the mid-acromium (MAC) and the mid-greater trochanter (MGT). Figure 4.7
shows the markers and joint center locations used for this segment.
Figure 4.7. Locations Involved on Defining the Trunk.
The trunk vector, expressed in the laboratory coordinate system from the mid-
greater trochanter, LPMGT, to the mid-acromium, LPKiAC, was defined as:
55


LP**=LPu4c-LP** (4-20)
The trunk excursion was measured as the maximum and the average of the excursion
angles and the distance from MAC to MGT. In order to measure the excursion angles
it was necessary to measure the orientation of the trunk vector with respect to the
coordinate seating system. For these calculations the trunk vector was considered as a
free vector. Equation (4.16) was used to relate these quantities.
LP~=£R"P~ (4.21)
SS Ptrunk was the trunk vector expressed in the seating coordinate system, and SSLR
was the rotation matrix between the seating and the laboratory coordinate systems.
This rotation matrix was defined based on the unit vectors of the seating coordinate
system as ssP~ ^ss ^ss ] (4.22)
From Equation (4.21), the vector ssPTmnk was calculated as:
^=U^)"1-L^nU* SSZtrunk l] (4-23)
These quantities are shown in Fig. 4.8 where the free trunk vector has been moved to
the origin to the seating coordinate system. The coordinates ssxmmk, SSytnmk, and
SSztrunk are shown in the scheme as well as the angles involved measuring trunk
excursion.
56


XL
Yl
Yss
Figure 4.8. Trunk Vector Expressed in the Seating Coordinate System.
4.4.1.1 Flexion/Extension Trunk Angle
This angle is measured on a plane parallel to a plane formed by the Y-axis and
Z-axis of the seating system, which corresponds to the sagittal plane. Figure 4.9
shows how this angle is defined by the projection of the trunk vector (from MGT to
MAC) on the plane described before and the axis Zss-
This angle is denoted by cc.
(4.24)
57


4.4.1.2 Lateral Flexion/Extension Trunk Angle
This angle is measured on a plane parallel to a plane formed by the X-axis and
Z-axis of the seating system, which corresponds to the frontal plane. Figure 4.10
shows how this angle is defined by the projection of the trunk vector on the plane
described before and the axis Zss.
This angle is denoted by fi.
P
= tan
( SS \
trunk
ssz
V. trunk J
(4.25)
58


Figure 4.10. Lateral Flexion/Extension Trunk Angle.
4.4.1.3 Trunk Length
In addition to the previous angles defined the distance between the MAC and
the MGT was measured in order to see if the trunk was expanding or contracting
during the trials. This distance was calculated as the length of the trunk vector.
d \Ptrunk I = 1j{SSxtrunk ) (4-26)
4.4.2 Wrist Trajectory
The analysis of the wrist trajectory was based on the location of the
functionally dominant wrist. In order to visualize the trajectory of each individual, the
trajectory of this location was calculated with respect to auxiliary coordinate system
59


explained in section 4.1.3. To obtain the coordinates with respect to that frame, the
following matrix equation was used. =LAT AP^ (4.27)
The location of the wrist, given by the human motion system was LPWrist,
laT was the transformation matrix, and APvrist was the location of the wrist with
respect to the auxiliary coordinate system. The transformation matrix was obtained
from the unit vectors corresponding to the auxiliary coordinate system as follows:
L
A
T =
Ia
0
J, K
A
0
A I;
0
MGTO
(4.28)
The quantity LPMGT0 is the location of the midpoint of the greater trochanters
location at the beginning of the task. Finally, from the equation 4.21, the location of
the wrist with respect to the auxiliary coordinate system was calculated as:
AP^,={LA'-LP.*, (4.29)
4.4.2.1 Path Length
The calculation of the path length during a given task is based on the
summation of the linear distances between two consecutive locations of the wrist.
Figure 4.11 shows two consecutives locations of the wrist during a given task:
(A/*wnst)i+i and (APwrist)i are the locations of the wrist at frames i and i+1.
60


The length between 2 points was approximated to ALj, which was calculated
as following. ALt = = \(APWrist )I+I (APWrist \
Equation 4.24 now can be written as:
ALf = V(Ax,. )2 + (Ay, )2 + (Azt f
(4.30)
(4.31)
Then the summation of all lengths becomes the total path length, this is:
Z = £A£, (4.32)
=1
Where N is the number of frames obtained from the human motion analysis.
61


4.4.2.2 Determination of Cycles during the Elliptical
Path Task
In order to perform the analysis of the path length per cycle during the
elliptical path test, it was necessary to determine the beginning and the end of every
cycle. Figure 4.12 shows how these two instants were determined; the horizontal line
that joints the two markers located at the end of the pegs was used as reference. The
beginning and the end of each cycle occurred when the projection on a horizontal
plane of the wrist location crossed that line.
End:
Frame j
Figure 4.12. Determination of the Duration of the Cycles.
If the cycle started at frame j and ended at frame k, the path length
k
corresponding to this cycle was obtained using ^ AL. (4.33)
>=j
62


4.4.2.3 Reaching Ratio for the Lateral and Forward
Reaching Task
Another quantity based on the wrist location was the reaching distance during
the lateral and forward reaching task. In order to perform the analysis of this measure
the arm length was defined as the summation of the lengths corresponding to the arm
and the forearm. The length hand was not included since the marker set utilized did
not use any markers on the fingers. The arm was defined as the segment from the
acromium to the elbow and the forearm as the segment from the elbow to the wrist.
Equation 4.34 shows how the arm length was calculated for a right-handed person
using the coordinated from the laboratory system.
(4.34)
4 =
LP LP a. LP LP
1 RAC 1 RE ~r rRE rRW
Where RAC is the right acromium location, RE the right elbow location, and RW the
right wrist location. Since this quantity was evaluated for every single instant there
was a minimum variation on its value. An average value was considered for the ratio
calculations.
4.4.2.3.1 Lateral Reaching Ratio
The lateral reaching distance is defined as the difference between the
maximum lateral reaching distance and the arm length. Figure 4.13 shows how this
distance was measured with respect to the wrist location, when a right-handed
individual performed a lateral reaching.
63


Ann Length
Figure 4.13. Lateral Reaching Distance for a Right-Handed Subject.
The lateral reaching distance (LRD) in this case was defined as:
LRD = Maximum Lateral Distance La (4.35)
In order to compare the results from different persons, the lateral reaching
ratio was defined as the quotient of the lateral reaching distance over the arm length.
Lateral Reaching Ratio = LRR =
LRD
La
(4.36)
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4.4.2.3.2 Forward Reaching Ratio
The forward reaching distance was defined as the difference between the
maximum forward reaching distance and the arm length. Figure 4.14 shows how this
distance was measured with respect to the wrist location, when a right-handed
individual performed a forward reaching.
Arm Length
Figure 4.14. Forward Reaching Distance for a Right-Handed Subject.
The forward reaching distance (FRD) in this case was defined as follows.
FED = Maximum Forward Distance La (4.37)
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The forward reaching ratio was defined as the quotient of the lateral reaching
distance over the arm length.
Forward Reaching Ratio = FRR =
FRR
La
(4.38)
4.4.2.4 Vertical Distance from Acromium to Wrist
This quantity was calculated in order to measure how subjects kept the wrist
height with respect to the acromium level. Figure 4.15 shows the scheme of how this
distance was calculated for a right-handed person.
The locations of the corresponding acromium and wrist were considered to
calculate the distance as follows:
dAW =( ^acromium ^wrist \^L (4.39)
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4.4.3 Posture
The analysis of posture was performed by measuring angles relative to the
position of the main segments of the body. For the analysis, the mid acromium
(MAC) and the mid greater trochanter (MGT) were the considered locations. In
addition to those locations, two new ones were defined to analyze posture: the
midpoint to the line that jointed the two knee locations (MK) and the midpoint to the
line that jointed the two ankle locations (MA). Figure 4.16 shows the scheme of the
template utilized to measure posture: trunk-leg and knee angles.
Figure 4.16. Posture Angles.
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4.4.3.1 Trunk-Leg Angle
This angle is based on the locations of the mid acromium (MAC), mid greater
trochanter (MGT), and the midpoint of the knee locations (MK). The expression to
evaluate this angle was:
4.4.3.2 Knee Angle
This angle is based on the locations of the mid greater trochanter (MGT), the
midpoint of the knee locations (MK), and the midpoint of the ankle locations (MA).
The expression to evaluate this angle was:
4.4.3.3 Leg Deviation Angle
Another measures to analyze posture were the leg deviation angles. These
angles were measured on a horizontal plane between the projection of the leg
segments and the Y-axis of the seating coordinate system. Figure 4.17 shows the
angles 0i and 02, measured between the projections of the legs and the Y-axis
direction (represented as the dashed line). The results of this analysis were presented
with respect to the functionally dominant side since the reaches were in that direction.
A positive angle deviation for the dominant side leg indicates that the leg is deviating
Trunk-Leg Angle = cos
(4.40)
Knee Angle = cos
(4.41)
68


towards the dominant side and a positive angle deviation for the non-dominant side
indicates that the leg is deviating towards the non-dominant side as shown in Fig.
4.17.
The equations to evaluate these angles were
r(Lp -Lp \j
V 1 LX rLGT ) ,
-1
0, = cos
02 = cos 1
- >
L p
rIX rLGT || j
(LP JP
V 1 RK 1RGT ) ^ SS
P -Lp
* DK i I
RK x RGT
(4.42)
(4.43)
4.4.4 Center of Pressure (COP)
Based on the pressure distribution data collected by the FSA system, its
software was able to calculate the location of the center of pressure during the tasks.
If t represents the time when the data was collected, A the area of each single
cell (lin2), i the number of the cell that goes from 1 to 256, and P(,,t) the pressure at
that cell, the total force P at that time was calculated as:
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(4.44)
256
256
pco=Z(/W^) = ^-2>w:
<=i
i=l
The coordinates of the center pressure were calculated as:
256
(xcop\t)

0.0 0.1)
256
2Xo
1=1
(4.45)
256
(ycop)ft) ~

256
i=l
(4.46)
Where x^and are the locations of the cell i at time t.
Figure 4.18 shows the orientation of the x and y axes on the pressure mat with
respect to a right-handed person.
P
Figure 4.18. Resultant Force and Center of Pressure Location on the FSA Mat.
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4.4.4.1 COP Displacement
This measure was performed to appreciate how the COP moved from its
initial location. The COP displacement was measured in two directions: frontal and
lateral. For a right-handed person the equations were:
Lateral: A(XCOp )(,) (XCOF )(0 (XCOP )(0) (4.47)
Frontal: A(Tcop )(o = (ycop )(o ~ Cvcop )(o) (4.48)
As well as the angle measures, the average of the COP displacement will be
utilized for comparison.
2 (A^COP )(t)
Ax COP = ^-------- (4-49)
(^COP )(/)
Ay cop ----- (4.50)
Where N was number of instants that the FS A system collected. In case a left-
handed person was tested, the directions of the axes were rotated 90 about the z-axis
and the lateral direction became the y direction and the frontal direction was
corresponding to the x direction.
4.4.4.2 Root Mean Square (RMS) of the Cop Displacement
Another quantity to measure the excursion of the COP is the RMS of the COP
displacement. This measure is related to the amplitude of the movement on each
71


direction and it measures how far subjects move from the average location. RMS is
also related to the absolute value of the area between the curve and its average value.
Figure 4.19 shows graphs of two centers of pressure locations that have the same
average value. However the case (a) shows less amplitude and less area than case (b),
then case (a) will have a smaller value of the RMS compared to case (b).
Figure 4.19. Root Mean Square of the COP Displacement.
For a right-handed person the expressions are:
Lateral RMS = Lms =
1
Id* COP )(0 ^cop )
f=0
N
(4.51)
Frontal RMS = =
1
COP )(o Avcqp j2
f=0
N
(4.52)
Again, if the person tested was left handed, the Lrms was associated to the y-
axis and the Fms was associated to the x-axis.
72


4.5 Statistical Analysis
All data distributions were examined for normalicy, variables that did not
have an absolute value of skewness greater than 1 were deemed to be not normally
distributed. As sample size was small (n=10 per group), it was decided not to do
transformations and chose to use non-parametric statistics for those relevant analyses.
Any variables with outliers were examined to ensure that the number was a true entity
and not a mathematical error.
Parametric and non-parametric statistics were used to find significant
differences based upon their distribution. Parametric tests (student t-test) were done
when data was normally distributed and non-parametric (Wilcoxon) tests were done
when data was not normally distributed.
The p-value was set at an alpha of 0.1, a priori. Paired t-tests were used to
compare the performance of the same group in the scooter and the wheelchair. Also,
t-tests were used to compare the performance of the groups within the same seating
systems. All analysis was completed using the SPSS software.
Measurements from the wheelchair and scooter were compared for all
variables of interest (Trunk excursion, path length, reaching ratios, posture angles and
COP movement).
4.5.1 Comparison of Seating Systems
This comparison tests were performed in order to observe differences between
the performances in the wheelchair and scooter. Each measurement during the initial
73


reaching task was compared to the performance during the final reaching task in the
same seating system to observe the variation along the test on that seating system.
The measurements from both seating systems during the initial reaching tasks were
compared to see the differences at the beginning of the test. Similarly, the
measurements from both seating systems during the final reaching tasks were
compared to see the differences at the end of the test. In total, four comparisons were
performed from the reaching tasks. Measurements obtained from the elliptical path
task and the completion time from the can stacking task in the wheelchair were
compared to the results from the scooter. Figure 4.20 shows the comparison tests
performed for the measurements involved.
Wheelchair Scooter
Figure 4.20. Tests Performed for the Seating System Comparison. Arrows
indicate the Comparison Performed.
The comparison test results of the measurements path length, trunk excursion
and COP movement were used to accept or reject the hypothesis presented before in
Chapter 2.
74


4.5.2 Comparison of Groups
In order to compare the performances of the two groups, data from the same
task and the same seating system was compared. Figure 4.21 shows how the
comparisons were performed.
Comparison Group Subjects with MS
Figure 4.21. Tests Performed for the Group Comparison. Arrows indicate the
Comparison Performed.
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Full Text

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MEASUREMENT OF UPPER EXTREMITY PERFORMANCE AS A FUNCTION OF THE SEATING SYSTEM: A COMPARISON ON PEOPLE WITH MULTIPLE SCLEROSIS AND A COMPARISON GROUP by Francisco Castro B.S. Pontificia Universidad Catolica del Peru, 1998 A thesis submitted to the University of Colorado at Denver in partial fulfillment of the requirements for the degree of Master of Science Mechanical Engineering 2003

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by Francisco Castro All rights reseiVed

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This thesis for the Master of Science Degree by Francisco Castro has been approved by Ronald A L. Rorrer Dan D. Scott Date

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Castro, Francisco (M.S., Mechanical Engineering) MeasurementofUpper Extremity Performance as a Function of the Seating System: a Comparison on People with Multiple Sclerosis and a Comparison Group. Thesis directed by Assistant Professor Ronald A.L. Rorrer ABSTRACT Multiple Sclerosis (MS) is a neurological disease that causes fatigue and severe motor and sensory problems. Because of these symptoms, there is a decrease in mobility, as well as a reduced quality of life. In order to reduce those effects, subject with MS are usually prescribed with powered mobility aids. There are currently two different groups of powered mobility aids or seating systems; powered customized wheelchairs and motorized non-customized scooters. The election of the seating system depends on the level of the disease; the more severely disabled are prescribed with a customized wheelchair. It was hypothesized, based on the observation of medical personnel, that subjects with MS will have better postural support for their pelvis and trunk and will therefore have better upper extremity performance in a customized seating system (wheelchair) than in a non-customized seating system (scooter). Ten subjects with MS were tested in both a wheelchair and scooter on a I 0degree tilted surface. Additionally, ten healthy subjects were tested as a comparison IV

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group. A sequence of tasks while sitting was implemented in order to evaluate their performance These tasks involved lateral and forward reaches, a continuous movement around two pegs following an elliptical path, and can stacking. A measurement motion analysis and pressure mat systems were utilized to calculate biomechanical parameters as angles, path length and distance variations Statistical analyses were performed to compare the results of the customized and non customiZed seating system For subjects with MS, results showed no overall differences on using the two seating systems Some measurements on the body-seat interface showed greater values in the wheelchair, even though a subjective study was also performed on this group and its results showed that they felt more comfortable in the wheelchair. Subjects from the comparison group did not show any differences on using the two seating systems, and their performance was greater than the performance of the subjects with MS The study faced some limitations. Both seating systems were tested over a 4hour period, so chronic changes may not be identifiable As a pilot test, it may not be sensitive enough to measure the differences. This abstract accurately represents the contents of the candidate's thesis I recommend its publication. Ronald A.L. Rorrer v

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DEDICATION To: All members of my family

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ACKNOWLEDGMENTS I am grateful to my advisor, Ronald A. L. Rorrer, Ph. D., for his guidance, support and patience during the duration of the study. It is a pleasure to thank Donna J. Blake, M.D. and Dan D Scott, M.D who not only brought the idea for the project and the funding to make this research possible but also made valuable comments on this study. I am particularly indebted to Patrice M. Kennedy, MPT and Thomas Hearty, DPT., for their invaluable help and support during the data collection I must especially thank Shirley Fitzgerald, Ph.D. for her comments and help with the statistical analyses of the project. I also acknowledge Heather C. Lahaie, Theodore A. Zeiger and Edward G. Westhead for their invaluable support and technical help. My thanks to the Human Performance Laboratory, Rehabilitation Medicine Physical Therapy Program, University of Colorado Health Sciences Center where the motion analysis was performed. Finally, I wish to express my gratitude to the Pittsburgh Veterans Health Administration, Rehabilitation Research & Development, Centers of Excellence Program, which provided the funding for the study.

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TABLE OF CONTENTS Figures .............................. ................ .......................................................................... xv Tables ......................... ............................................................................................... xxi Nomenclature ........................................................................................................... xxiv Chapter 1. Introduction ................................................................................................................ 1 1.1 Multiple Sclerosis .................................................................................................... 1 1.2 Impact ofMS on Daily Llife Activities: Need of Mobility Aids ............................. 2 1.3 Seating Systems: Customized and Non-Customized .............................................. .3 1.4 Current Methods ...................................................................................................... 5 1.4.1 Posture ................................................................................................................... 6 1.4.2 Fatigue ................................................................................................................... 9 1.4.2.1 Qualitative Approach ....................................................................................... 1 0 1.4.2.2 Quantitative Studies ......................................................................................... 14 2. Hypothesis ................................................................................................................ 17 3. Methodology ............................................................................................................ 20 3.1 Population: Comparison Group and Subjects with MS ........................................ 21 3 .1.1 Comparison Group .............................................................................................. 21 3 .1.2 Subjects with MS ................................................................................................ 21 Vlll

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3.1.2.1 Consent Protocol .................. ; ........................................................................... 23 3 .1.2.2 Test Preparation ............................................................................................... 23 3.2 Test Equipment ...................................................................................................... 23 3.2.1 Measurement Motion Analysis System .............................................................. 24 3.2.2 Force Sensitive Applications (FSA) System ................. ..................................... 29 3.2.3 Synchronizing Device ......................................................................................... 30 3.2.4 Tilted Surfaces ................................ .................................................................... 32 3.2.5 Peg Holders ......................................................................................................... 34 3.2.6 Other Tools ......................................................................................................... 35 3.3 Test Description ..................................................................................................... 35 3.3.1 Previous Set-Up ........................................................... : ...................................... 35 3.3.2 Sequence ofTasks .................................. ............................................................ 36 3.3.2.1 Initial Lateral and Forward Reaching Task ..................................................... 36 3.3.2.2 Elliptical Path Task .......................................................................................... 38 3.3.2.3 Can Stacking Task ............................................ .............................................. 40 3.3.2.4 Final Lateral and Forward Reaching Task ...................................................... .40 3.3.3 Time Sequence .................................................................................................... 41 3.3.4 Randomization and Resting Procedure .............................................................. .42 3.4 Test Conditions ...................................................................................................... 43 4. Data Analysis ........................................................................................................... 44 4.1 Coordinate Systems ............................................................................................... 44 ix

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4.1.1 Laboratory Coordinate System ........................................................................... 44 4.1.2 Seating Coordinate System ................................................................................. 45 4.1.3 Auxiliary Coordinate System .............................................................................. 50 4.2 Reduced Marker Set. .............................................................................................. 51 4.3 Vector and Matrix Descriptions ............................................................................ .53 4.3.1 Vector Notation ................................................................................................... 53 4.3.2 Matrix Operators ................................................................................................. 53 4.3.2.1 Translation ................................................................. ..................................... 53 4.3.2.2 Rotation ............................................................................................................ 54 4.3.2.3 Translation and Rotation ................................................................................. .54 4.4 Calculations ............................................................................................................ 55 4.4.1 Trunk Excursion ..................................... ............................................................. 55 4.4.1.1 Flexion/Extension Trunk Angle ....................................................................... 51 4.4.1.2 Lateral Flexion/Extension Trunk Angle .......................................................... 58 4.4.1.3 Trunk Length ............................................................................... .................. 59 4.4.2 Wrist Trajectory .................................................................................................. 59 4.4.2.1 Path Length ............................ ......................................................................... 60 4.4.2.2 Determination of Cycles during the Elliptical Path Task ................................ 62 4.4.2.3 Reaching Ratio for the Lateral and Forward Reaching Task ........................... 63 4.4.2.3.1 Lateral Reaching Ratio ................................................................................. 63 4.4.2.3.2 Forward Reaching Ratio ............................................................................... 65 X

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4.4.2.4 Vertical Distance from Acromium to Wrist.. ................................................... 66 4.4.3 Posture ................................................................................................................ 67 4.4.3.1 Trunk-Leg Angle ............................................................................................. 68 4.4.3.2 Knee Angle ...................................................................................................... 68 4.4.3.3 Leg Deviation Angle ....................................................................................... 68 4.4.4 Center of Pressure (COP) .................................................................................... 69 4.4.4.1 COP Displacement ........................................................................................... 71 4.4.4.2 Root Mean Square (RMS) of the COP Displacement ..................................... 71 4.5 Statistical Analysis ................................................................................................. 73 4.5.1 Comparison of Seating Systems ......................................................................... 73 4.5.2 Comparison ofGroups ........................................................................................ 75 4.5.3 Order Performed Comparison ................ : ............................................................ 76 4.5.4 Correlation Analysis ........................................................................................... 76 5. Results ...................................................................................................................... 78 5.1 Result Examples ..................................................................................................... 78 5.1.1 Trunk Excursion Results ..................................................................................... 78 5.1.2 Wrist Trajectory Results ..................................................................................... 82 5.1.3 Posture Results ................................................................................................... 90 5.1.4 Center ofPressure Results .................................................................................. 95 5.2 Data Summary ....................................................................................................... 97 5.2.1 Seating System Comparison Results .................................................................. 97 XI

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5.2.1.1 Lateral and Forward Reaching Task Results ............................ ...................... 97 5.2.1.2 Elliptical Path Task Results ........................................................................... 104 5.2.1.3 Can Stacking Task Results ............................................................................. 108 5 .2.2 Order Performed Comparison Results .............................................................. 1 08 5.2.3 Correlation Test Results .................................................................................... 109 5.2.4 Group Ranking ............................................................................... .................. 109 6. Discussion, Conclusions and Recommendations ................................................... 113 6.1 Discussion ............................................................................................................ 113 6.2 Conclusions .............................................................................. ........................... 116 6.3 Recommendations ................................................................................................ 117 Appendix A. Colorado Multiple Institutional Review Board .................................................... 120 B. Veterans Affairs Research Consent Form ............................................................ 122 C. Medical/Demographic Questionnaire .................................................................. 127 D. Physical Exam and Anthropometric Measurements ............................................ 132 E. Procedures ............................................................................................................ 136 E.1 Subject preparation prior to testing ............................................................... 136 E.2 Instructions given to subjects during testing ................................................. 137 E.2.1 Test 1: Lateral and Forward Reaching Task ............................................... 137 E.2.2 Test 2: Elliptical Path Task. ........................................................................ 137 E.2.3 Test 3: Can Stacking Task .................................... .................. ... ................. 137 Xll

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E.3 Data Collection Procedure ............................................................................. l38 E.3.1 Prior to testing ............................................................................................ 138 E.3.2 Prior to each Task ....................................................................................... l38 E.3.3 During the Task ......................................................................................... 139 E.3.4 Subsequent to the Task ............................................................................... l39 E.4 Digitization Process using the Peak Motus System ...................................... 139 F. Triggering Device ................... ;.; ....................................... ... .................. ............. 140 G. Marker Locations ................................................................................................. 142 G.1 Acromium Marker ......................................................................................... 143 G.2 Elbow Markers .............................................................................................. 143 G.3 Wrist Markers ............................................................................................... 144 G.4 Greater Trochanter Markers .............. : ...................................... ..................... 145 G.5 Knee Markers ................................................................................................ 145 G.6 Ankle Markers ............................................................................................... 146 H. Tilted Surfaces ..................................................................................................... 14 7 I. Peg Holder ........................................................................................................... 152 J. Individual Data for the Seating System Comparison ........................................... 159 J.1 Results from Subjects with MS ...................................................................... l59 J.l.l Lateral and Forward Reaching Task ........................................................... 159 J.1.2 Elliptical Path Task ..................................................................................... 162 J.l.3 Can Stacking Task ............................................................ .... ........ ............... 164 Xlll

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J.2 Results from the Comparison Group ............................................................. 165 J.2.1 Lateral and Forward Reaching Task ........................................................... 165 J 2 2 Elliptical Path. Task ........ ... ................... ... ..... ..... ..... ................ .. .............. 168 J.2.3 Can Stacking Task ....................................................................................... 169 K. Individual Data for the Order Performed Comparison ........................................ 170 K.1 Results from Subjects with MS ..................................................................... 170 K .l.1 Lateral and Forward Reaching Task ....... ..... ...... ............. ....... ............. 170 K 1.2 Elliptical Path Task ................................. .................................... ............. 17 4 K.1.3 Can Stacking Task ................................... ................................................. 175 K 2 Results from tb.e Comparison Group ........................................................... 176 K 2.1 Lateral and Forward Reaching Task .......................................................... 176 K.2.2 Elliptical Path Task ........................ : ........................................................... 180 K.2.3 Can Stacking Task ....................................................................... ............. 181 References ........................... ......................................................................... ............ 182 XIV

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FIGURES Figure 2.1 Hypothesized Performance Variation During Testing ........................................... 19 3.1 Marker Set .............................................................................................................. 24 3.2 Laboratory Set Up for a Right-Handed Person ...................................................... 26 3.3 Seventeen-Marker Calibration Frame .................................................................... 27 3.4 Laboratory Coordinate System Frame ....... ... .................... .... ................................. 28 3.5 Video Processing ....................... ... ......................................................................... 29 3.6 Pressure Distribution on the FSA Mat. ..... ........................................................... .30 3.7 Measurement Systems ....................................... ....................... ........................... 31 3.8 Tilted Surfaces ........................... .... ............. ......... ......... ....... ................................ 33 3.9 Seating System Location on the Tilted Surface ............... .................................... .33 3.10 Peg Holder ........................................................................................................... 34 3.11 Frontal View ofthe Lateral Reaching Task for a Right-Handed Individual .................................................................................... 37 3.12 Lateral View of the Frontal Reaching Task for a Right-Handed Individual ................................................................................... 38 3.13 Peg Locations for a Right-Handed Person .......................................................... .39 XV

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3.14 Can Stacking Test Arrangement ......................................................................... .40 3.15 Time Sequence (minutes) .................................................................................... 42 4.1 Laboratory Frame Reference ................................................................................. 45 4.2 Coordinate System Rotations ................................................................................ .46 4.3 Seating Coordinate System ................................................................................... .47 4.4 Vectors P, Q, and R attached to the Seating System ............................................ .48 4.5 Auxiliary CoordinateSystem ................................................................................. SO 4.6 Marker Set Locations and Calculated Joint Centers ....... ............................. : ........ 52 4.7 Locations Involved on Defining the Trunk ............................................................ 55 4.8 Trunk Vector Expressed in the Seating Coordinate System .................................. 57 4.9 Flexion/Extension Trunk Angle ............................................................................. 58 4.10 Lateral Flexion/Extension Trunk Angle .............. ; ............................................. 59 4.11 Distance between to Consecutive Locations ........................................................ 61 4.12 Determination of the Duration of the Cycles ....................................................... 62 4.13 Lateral Reaching Distance for a Right-Handed Subject. ..................................... 64 4.14 Forward Reaching Distance for a Right-Handed Subject.. .................................. 65 4.15 Vertical Distance from Acromium to Wrist ......................................................... 66 4.16 Posture Angles ..................................................................................................... 67 4.17 Leg Deviation Angles .......................................................................................... 69 4.18 Resultant Force and Center of Pressure Location on the FSA Mat ..................... 70 4.19 Root Mean Square of the COP Displacement ...................................................... 72 XVI

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4.20 Tests Performed for the Seating System Comparison ......................................... 74 4.21 Tests Performed for the Group Comparison ....................................................... 75 4.22 Tests Performed for the Order Performed Comparison ....... ........................... ... 76 5.1 Trunk Excursion Angles during Lateral and Forward Reaching Task for a Subject with MS in the Wheelchair ............................................................... 79 5.2 Trunk Length Variation during Lateral and Forward Reaching Task for a Subject with MS in the Wheelchair ............................................................... 80 5.3 Trunk Excursion Angles during the Elliptical Path Task for a Subject with MS in the Wheelchair ....................................................................... 81 5.4 Trunk Length Variation during the Elliptical Path Task for a Subject with MS in the Wheelchair ................... ." .................................................. 81 5.5 Trajectory of the Wrist during the Forward and Lateral Reachi:D.g Task for a Subject with MS in the Wheelchair ...................................................... 83 5.6 Trajectory of the Wrist during the Forward and Lateral Reaching Task for a Subject with MS in the Scooter ............................................................ 83 5.7 Trajectory of the Wrist during the Forward and Lateral Reaching Task for a Comparison Group Subject in the Wheelchair ..................................... 84 5.8 Trajectory of the Wrist during the Forward and Lateral Reaching Task for a Comparison Group Subject in the Scooter ........................................... 84 5.9 Right Wrist Trajectory during the Elliptical Path Task.for a Subject with MS in the Wheelchair ....................................................................... 85 xvii

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5.10 Cycle during the Elliptical Path Task ........................ ..... ....... ...... ........................ 86 5.11 Right Wrist Trajectory during the Elliptical Path Task.for a Subject with MS in the Scooter ............................................................ .............. 87 5.12 Right Wrist Trajectory during the Elliptical Path Task.for a Comparison Group Subject in the Wheelchair ...................... ................. ............... .... ............ 87 5.13 Right Wrist Trajectory during the Elliptical Path Task.for a Comparison Group Subject in the Scooter .......................... ................................... .... ............ 88 5.14 Vertical Distance from the Wrist to the Acromium during the Lateral and Forward Reaching Task for a Subject with MS in the Wheelchair ... ................. 89 5.15 Vertical Distance from the Wrist to the Acromium during the Elliptical Path Task for a Subject with MS in the Wheelchair ............. .............. 89 5.16 Arm Length Variation during the Lateral and Forward Reaching Task for a Subject with MS in the Wheelchair ................................................... 90 5.17 Posture Angle Results during the Lateral and Forward Reaching Task for a Subject with MS in the Wheelchair ................................................... 91 5.18 Posture Angle Results during the Elliptical Path Task for a Subject with MS in the Wheelchair ......................................................................................... 91 5.19 Leg Deviation Angles during the Lateral and Forward Reaching Task for a Subject with MS in the Wheelchair ................................ .................. 92 5.20 Leg Deviation Angles during the Lateral and Forward Reaching Task for a Subject with MS in the Scooter ......................................................... 93 XVlll

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5.21 Leg Deviation Angle during the Elliptical Path Reaching Task for a Subject with MS in the Wheelchair ................................................... 94 5.22 Leg Deviation Angle during the Elliptical Path Reaching Task for a Subject with MS in the Scooter ......................................................... 94 5.23 Data provided by the FSA System for a Given Frame ........................................ 95 5.24 COP Displacement during the Lateral and Forward Reaching Task for a Subject with MS in the Wheelchair .................................................................... 96 5.25 COP Displacement during the Elliptical Path Task for a Subject with MS in the Wheelchair ......................................................................................... 96 5.26 Can Stacking Completion Time Results ............................................................ 1 09 5.27 Path Length per Cycle Results ........................................................................... 11 0 5.28 Path Length per Cycle Variation ............. .......................................................... 111 5.29 Path Length per Cycle per Arm Length Results ................................................ 112 F .1 Wiring of the Triggering Device ......................................................................... 140 G.1 Anatomical Landmarks ....................................................................................... 142 G.2 Anterior (Frontal) View of the Right Acromium Marker ................................... 143 G.3 Anterior (Frontal) View of the Right Elbow Markers ........................................ 144 G.4 Anterior (Frontal) View of the Right Wrist Markers .......................................... 144 G.5 Anterior (Frontal) View of the Right Greater Trochanter and Right Knee Markers ............................................................................................. 145 G.6 Anterior (Frontal) View ofthe Right Ankle Marker ........................................... 146 XIX

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H.1 Main Wooden Ramp ................ .......................................................................... 148 H.2 Main Wooden Ramp. Side View, Section A-A .................................................. 149 H.3 Auxiliary Wooden Rainp .................................................................................... 150 H.4 Auxiliary Wooden Rainp. Side and Bottom View .............................................. 151 1.1 Peg Holder. Lateral View ..................................................................................... 153 1.2 Peg Holder. Frontal View ..................................................................................... 154 1.3 Peg Holder. Detail A ............................................................................................ 155 14 Peg Holder. Detail B ........................................................................................... ;.156 1.5 Peg Holder. View from A-A ................................................................................. 157 1.6 Peg Holder. Detail C and Section B-B ................................................................. 158 XX

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TABLES Table 5.1 Lateral and Forward Reaching Task Results for Subjects with MS ...................... 99 5.2 Lateral and Forward Reaching Task Results: Seating System Comparison Performed on Subjects with MS .......................................................................... 1 00 5.3. Lateral and Forward Reaching Task Results for the Comparison Group ........... 101 5.4. Lateral and Forward Reaching Task Results: Seating System Comparison Performed on the Comparison Group ............................................. 1 02 5.5 Comparison of Means p-value between Groups for the Lateral and Forward Reaching Task ............................................................................................. ........ 103 5.6 Elliptical Path Task Results: Seating System Comparison Performed on Subjects with MS ...................... ........................................................................... 1 05 5.7.Elliptical Path Task Results: Seating System Comparison Performed on the Comparison Group ............................................................................................... 1 06 5.8 Comparison ofMeans p-value for the Elliptical Path Test .................................. 107 5.9 Can Stacking Tasks Results ................................................................................. 108 J.l Lateral and Forward Reaching Task Results from Subjects with MS. Seating System Comparison ................................................................................ 159 xxi

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J.2 Elliptical Path Task Results from Subjects with MS. Seating System Comparison .......................................................................................................... 162 J.3 Can Stacking Task Results from Subjects With MS Seating System ............................................................................................ 164 J.4 Lateral and Forward Reaching Task Results from the Comparison Group. Seating System Comparison ................................................................................ 165 J.5 Elliptical Path Task Results from the Comparison Group Seating System Comparison ............................................................................................. 168 J.6 Can Stacking Task Results from the Comparison Group. Seating System Comparison ......................................................... ........ ............. 169 K.1 Lateral and Forward Reaching Task Results from Subjects with MS. Order Performed Comparison ..... .............. ........................................................... 170 K.2 Elliptical Path Task Results from Subjects with MS Order Performed Comparison ................................. ............... .... ................................... 17 4 K.3 Can Stacking Task Results from Subjects with MS. Order Performed Comparison ....... .. ....... ........................................................................ 17 5 K.4 Lateral and Forward Reaching Task Results from the Comparison Group. Order Performed Comparison .................. ........ ........ ... ................. ... ......... ........... 176 K.5 Elliptical Path Task Results from the Comparison Order Performed Comparison ........................................................................................ 180 XXII

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K.6 Can Stacking Task Results from the Comparison Group. Order Performed Comparison ......................... ............................................................... 181 XXlll

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NOMENCLATURE A: Auxiliary Coordinate System. A,B: Frames. a,b,c,m: Scalars. a: Flexion Extension Trunk Angle. p: Lateral Flexion Extension Trunk Angle. d: Trunk Length. dAw: Vertical Distance from Acromium to Wrist COP: Center of Pressure. DV AMC: Denver Veterans Affairs Medical Center. EMG: Electromyography. FIS: Fatigue Impact Scale. FRD: Frontal Reaching Distance. FRR: Frontal Reaching Ratio. F RMs: Frontal Root Mean Square. FSA: Force Sensitive Applications/Force Sensing Array i,J,K: Unit Vectors. Lo: Distance from the Acromium to the end ofthe middle finger tip. L: Laboratory Coordinate System. L: Path Length. La: Arm Length. LRD: Lateral Reaching Distance. LRR: Lateral Reaching Ratio xxiv

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FRMs: MS: N: P,Q,R: p: p-value: (}. AR. B RMS: ROM: S: SS: S-VHS: AT. B X, Y, Z: x,y,z: Lateral Root Mean Square. Multiple Sclerosis. Number of frames. Vectors. Pressure on the body-seat interface. Probability value of two quantities being different for a specific test. Leg Deviation Angle. Rotation Matrix of frame B with respect to frame A Root Mean Square. Range of Motion. Vector defining the location of the seating system makers. Coordinate System attached to Seating System. Super VHS (Video Home System). Description Matrix of frame B with respect to frame A Coordinate System Axis. Vector Components. XXV

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l.lntroduction 1.1 Multiple Sclerosis Multiple Sclerosis (MS) is an inflammatory disease of the central nervous system. This neurological disease involves repeated episodes of inflammation of nervous tissues in any area of the central nervous system: brain and spinal cord. This process is caused when immune cells of the own body attack the nervous system. The inflammation destroys the covering of the nerve cells in that area (myelin sheath), leaving multiple areas of scar tissue (sclerosis) along the covering of the nerve cells. This results in slowing or blocking the transmission of nerve impulses in that area, leading to the symptoms of MS. Because of the variable distribution of demyelination throughout the central nervous system, people with MS may experience disorders of balance, coordination, strength, sensation, vision, and muscle tone1 Symptoms vary because the location and extent of each attack varies. There is usually a stepwise progression of the disorder, with episodes that last days, weeks, or months alternating with times of reduced or no symptoms (remission). Recurrence (relapse) is common although non-stop progression without periods of remission may also occur. The prevalence of MS seems to be related to the latitude of residency. In equatorial areas, the prevalence is less than 1 per 100,000, and in the southern United 1

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States and southern Europe it is 6 to 14 per 100,000 The highest prevalence occurs in Canada, northern Europe and the northern United States and varies from 30 to 80 per 100,0002 There are 250,000 to 350,000 cases in the United States3 The Veterans Health Administration provides care to approximately 20,000 of these cases Estimates place the average direct and indirect health-related costs at $35,000 per patient with MS per year4 MS is the third most common cause of disabling illness in individuals between the ages of 15 and 50 The mean age of onset is 32 years old2 This disease inv olves twice as many women as men However, MS is, on average, more severe in male subjects. 1.2 Impact of MS on Daily Life Activities: Need of Mobility Aids The most common symptoms of MS are fatigue and severe motor and sensory problems Because of these symptoms, there is a decrease in mobility, as well as a reduced quality of life in people with MS Symptoms can worsen if the patient is exposed to heat or prolonged physical activity5 To avoid worsening symptoms, people with MS will often reduce physical activity and recreation. In order to provide a better quality of life, as well as improved mobility, mobility aids, such as manual wheelchairs, powered wheelchairs and motorized scooters, have been prescribed for people with MS In 1983, about 40% of the MS population required the use of these mobility aids for community and home mobility6 2

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These mobility aids or seating systems are prescribed for people with MS based on their level of disability, with the more severely disabled individuals being provided a customized power wheelchair. Initially a patient may use a manual wheelchair and then, coincident with progression of the disease, may start using a powered mobility aid. When a person with MS loses the ability to propel a manual wheelchair, develops quadriparesis and/or marked fatigability, a powered mobility aid may be needed7 Once power mobility becomes necessary for the patient, the medical providers and the patient decide which type of powered seating system is most appropriate Most of the people with MS prefer a motorized scooter because they feel they have more control of their movements and that they look less disabled. However, use of scooters is controversial in the medical community This is based on the observation of patients sitting in the two different motorized seating systems. It is commonly thought t}:lat people with MS using scooters will decrease their physical activity faster than powered wheelchair users do secondary to increased fatigue from a non-supportive seating system. 1.3 Seating Systems: Customized and Non-Customized When wheelchairs are prescribed, specifications such as tilt angle, back angle, depth, width and kind of cushion, leg and trunk support, headrest, armrest and footrest position, etc. can be measured and adjusted by a trained clinician in order to provide a custom fit for each individual. For all these reason a powered wheelchair can be classified as a customized seating system. On the other hand, when a scooter is 3

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issued, a minimum number of variables can be addressed, such as seat height, armrest position and headrest position. This generic system is made to fit many different body sizes Scooters are essentially "off-the-shelf' mobility aids and can be identified as non-customized seating systems. Several studies have shown the importance of seating systems in the life of the users. A study in an elderly population showed that if a coordinated wheelchair management approach by trained individuals is not used, it could result in decreased independence and deterioration of physical condition of the users8 A proper seating system may increase a person's tolerance to wheelchair usage and improve cardiac and respiratory function. On the other hand, if the seating system is inappropriate and results in poor posture, it can cause disk degeneration and low back pain9 Poor posture can result in spinal deformities, increased spasticity and pain in the neck and shoulders, increased risk of pressure ulcers and decreased respiratory function10'u. The purpose of this pilot study is to investigate if body posture in different seating systems contributes to the development of increased fatigue and reduced performance in people with MS. This requires measurement of posture, performance, and fatigue during several tasks to compare results from different seating systems Since this study involves people with MS from the Veterans Health Administration, the results can be applied only to the population used. Vollmer3 found that there are some differences between the population used and the general population. The percentage of males with MS in the general population is 4

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approximately 17%, while in the VA population used for this study; the 85% of the subjects were male. 1.4 Current Methods A literature review was performed to determine current methods being used to evaluate performance, posture and fatigue, the variables being examined in this study of power mobility aids One of the quantities most utilized used to measure performance is the completion time of a task. Hand function tests, such as the Jebsen Test12 and the Nine Hole Peg Test13, use task completion times to evaluate subjects. A faster completion time indicates better performance during these fine motor skill tests. Reaching distance and range of motion (ROM) have been used to measure performance in people with Parkinson's disease during reaching tasks performed while standing14. ROM has been defined as thoracic rotation, lateral trunk flexion, total rotation, and forward trunk flexion. In Schenkman's study, participants demonstrated a shorter reaching distance than controls. In the latter group, it was noted younger individuals have greater reaching distances than older individuals. All measurements were collected by a three-dimensional motion analysis Posture and fatigue are two of the most common variables used to evaluate performance. Current studies of these variables are presented below. 5

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1.4.1 Posture Posture is defined as "the position or bearing of the body" (Webster's Medical Dictionary) and refers to the overall alignment of the various body parts to each other when a person is standing in a relaxed stance. The concept of posture has been studied in several experiments, where it has been related to the center of pressure (COP) of the body-seat interface. Several articles1516 have shown that posture can be measured by locating markers on specific locations of the subject's body, and analyzing the movements as the experiment was performed. In order to analyze these movements, different motion analysis systems to capture the signals have been used Kamper16 has performed several studies on the postural stability of wheelchair users and control subjects exposed to external perturbations. Several markers were located on the user's body in order to analyze posture with a video camera. Those markers were located over multiple positions, including : greater trochanter, iliac crest, lateral extent of the tenth rib, axilla, lateral base of the neck, and ear This set of markers allowed estimation of rotation of the pelvis, lower torso, upper torso, neck and head. For this study, rotation was quantified in terms of the change in angle from the starting position. External perturbations were performed using a platform able to tilt. The center of pressure (COP) was calculated from a force platform and was compared to those that were obtained from the video The platform where the 6

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wheelchair was located was able to rotate 30 degrees in either the anterior-posterior or the lateral plane. In another study, Harrison17 studied posture in people with cervical pain and in a group of controls. Reflective markers were placed on the ear, shoulder, and lateral malleolus Marker positions were recorded and horizontal distances and angles were compared. Curtis18 performed a study of wheelchair basketball players to compare the effects of using wheelchair trunk and lower extremity stabilization on sitting trunk mobility, and functional reach of wheelchair users. The test was repeated 3 times with different conditions: without a belt, with a neoprene belt and with webbing tight belt. In order to capture the motion of the participants, the experiment was performed in a darkened motion analysis laboratory using the Motion Analysis Expert Vision Flextrak program. The markers were placed on the lateral aspect of the right spine of the scapula, the right trochanter and the knee joint line. A reflective sphere was also placed in the center of the wheelchair backrest. The study showed that there are substantial differences between the functional reach of the wheelchair users and the able-bodied control group. For subjects with low thoracic paraplegia, the functional reach was increased when the belts were used. Maltais15 (1999) proposed anatomical landmarks, as well as wheelchair landmarks, in order to perform sitting and standing tests on able-bodied subjects seated in wheelchairs. An articulated mechanical arm (Microscribe 3D, Inmersion 7

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Corporation) was used to digitize the landmarks The anatomical and wheelchair landmarks digitized, 27 in total, for each subject evaluation are the following: lateral malleolus (2), condyle of the femur (2), greater trochanter (2), anterior superior iliac spine (2), iliac crest (2), middle trunk (4 on each side), acromium (2), cervical vertebrae, xyphoid process, suprasternal notch, rear wheel center (2), and metal road markers (2). Additionally, the study analyzed the pressure distribution on the seat cushion using the Force Sensing Array (FSA) provided by Vista Med, Inc. A squared mat with 225 pressure sensors was used. The purpose of the study was to evaluate the variability of the mechanical parameters. The study suggested that the method proposed could be used as an accurate procedure to characterize the posture of subjects sitting in a wheelchair. However, using marker based video motion analysis is not the only method that has been used to measure posture. Bendix et.al.19 used inclinometers to measure trunk position and compare posture of healthy individuals during upper extremity tasks In this experiment the tasks consisted on moving 2 pins from one solitaire game to another Authors used a statometric technique, where the angles were measured while individuals were holding their position. Potten (1999i0 performed an experiment looking at forward reach in order to analyze the postural muscle responses in people with spinal cord injuries The author measured the COP using a force platform (Biovec 1000, AMTI). 8

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All these .studies show that reflective markers are commonly used to evaluate posture, especially when gross body movement is being analyzed. Small movements make the use of markers difficult due to the large size of the markers Pressure distribution and the COP displacement on the seat have also been shown to be important factors in the analysis of posture. 1.4.2 Fatigue Measurement of fatigue has been performed in several studies21"35. However, most of those measurements have been qualitative, utilizing questionnaires to evaluate the level of fatigue. The patients were asked about their ability to perform daily physical activities or tasks. Limitations of self report questionnaires used to quantify fatigue severity can be confounded by other symptoms of MS. Questionnaires are entirely subjective and require patients to make difficult retrospective assessments21 (Schwid 2002). In this study the authors presented the force as a quantitative measure and established the necessity of defining more rigorous and quantitative measures Everyone experiences fatigue at various times. For healthy individuals, a feeling of fatigue is temporary and is usually related to excessive physical activity, a sedentary lifestyle, poor nutrition, an increase in work or social responsibilities or lack of sleep With the appropriate interventions (rest sleep, better nutrition, or a change in stimulation) energy is rapidly restored Acute fatigue is thought to serve a protective function, alerting a person to the need for rest. Acute fatigue is, by 9

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definition, time limited. But for some people, fatigue is a daily experience that affects all parts of their lives. Rest may lessen the severity of chronic fatigue, but often it does not completely relieve it. Patients with chronic illnesses and those undergoing cancer treatment may need to alter their lifestyles to manage fatigue. Such alterations may be temporary (until the disease process is under control) or may require permanent changes in patterns of activity. According to the North American Nursing Diagnosis Association. guidelines, the major defining characteristic of chronic fatigue is the patient's self-report of a sustained and significant lack of energy. For MS22 the definition of fatigue is a sense of physical tiredness and lack of energy, distinct from sadness or weakness. 1.4.2.1 Qualitative Approach Fatigue is one of the most common and disabling symptoms of Multiple Sclerosis, regardless of the severity of the disease. Regarding people with MS, Krupp et al.22 defined fatigue as a sense of physical tiredness and lack of energy, distinct from sadness or weakness, Qualitative studies have shown that a great percentage of people with MS have both physical and mental fatigue during normal daily activities. Fatigue is present in 78 to 87% of the MS population, according to studies performed by Vercoulen et al.23, Freal et al.24 Ford et al.25 and Fisk et al.26 All these studies used questionnaires, to have people with MS scale different parameters. Krupp22 showed that the percentage of people with MS impacted by fatigue (87%) is greater than the percentage in healthy people (51%). Fatigue severity was 10

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assessed with a visual analog scale (VAS). Patients marked on a line the point that best described their fatigue. For that study, the author used a 100 mm scale. In 1995, Krupp27 studied the influence of several medications with a similar linear scale, called the Fatigue Severity Scale. Freal24 used a questionnaire of25 questions and found that 78% of the people with MS observed were affected by fatigue. Fisk26 found that fatigue could be present everyday in 40% of the MS population. In this study, Fisk noted that the actual ratings of fatigue are not typically included in routine quantitative evaluations. Chan28 presented an article summarizing the different tools (scales) used to measure fatigue performed by different authors: 1. Fatigue Severity Scale22 : The Fatigue Severity Scale (FSS) was developed and validated for the MS population. It was designed to describe the impact of fatigue on daily function. This scale consists of9 statements. For each of the statements, the subject selects from a scale of 1 to 7 to indicate the severity of the fatigue experienced (1 for no impact to 7 for highest impact). The total score of the FSS ranges from a low of 9 (fatigue has no impact) to a high of 63 (fatigue has a severe impact). 2. Fatigue Impact Scale26 : The Fatigue Impact Scale (FIS) consists of 40 questions grouped under the 3 domains of cognitive functioning, physical functioning, and psychosocial functioning. The subject rates the extent to which fatigue causes problems, from 0 for no problem to 4 for extreme problems. The total score 11

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ranges from a low of 0 (fatigue causes no problem) to a high of 160 (fatigue causes extreme problems). This scale provides a more comprehensive description of the areas of function in which fatigue has the most impact. Both the FSS and the FIS have been used in many clinical trials and outcome studies on the MS population. 3. Fatigue Descriptive Scale29 : The Fatigue Descriptive Scale (FDS) is a scale developed to evaluate the periodicity, severity, and quality of fatigue caused by MS. Based on the subject's responses, a score of 0 to 3 is assigned to each of the different categories associated with heat. The FDS is highly correlated with the FSS. 4. Modified Fatigue Impact Scale: The Clinical Practice Guidelines on Fatigue30 adopted the Modified Fatigue Impact Scale (MFIS) as the scale of choice for measuring fatigue in MS. Instead of using the 40 questions in the original Fatigue Impact Scale (FIS), this shortened version consists of21 questions, grouped under the same 3 domains. The rating scale for the MFIS remains the same as the one described for the FIS. 5. Multiple Sclerosis Quality ofLife Inventory31: The Multiple Sclerosis Quality of Life Inventory (MSQLI) is a tool designed to measure the impact of MS on the individual's quality of life. It consists of many standardized tools, including the Mental Health Inventory, and the Pain Effects Scale. The MFIS is a component of this quality of life tool. 12

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6. Fatigue Questionnaire and Sleep Questionnaire: The Clinical Practice Guidelines on Fatigue30 also recommend using the Fatigue Questionnaire and the Sleep Questionnaire to record the degree of fatigue that an individual experiences in a one-month time frame. The Fatigue Questionnaire categorizes the quality and severity of fatigue experienced by the individual, and the Sleep Questionnaire documents the individual's sleep patterns. Information from both questionnaires and from the MS Daily Activity Diary can be used to develop appropriate fatigue management strategies. Perceived exertion was also a measurement performed to observe the variation of the subject conditions. The Borg Perceived Exertion Scale32 is used to ask subjects how. their perceived exertion is. This tool uses scale from 6 to 20, 6 being the lightest case and 20 the hardest case, to rate the perceived exertion. During the present research a subjective was also performed using the Borg Perceived Exertion Scale and the Fatigue Impact Scale. Subjects with MS were asked to rate their level of perceived exertion and fatigue using those scales. The study consisted of a sequence of tasks performed in a customized and a non customized seating system. Subjects completed the scales before and after the sequence was completed in each seating system Results from the study showed that subjects perceived more exertion and were more fatigued when the tasks were completed in the non-customized seating system (scooter). Most of the subjects (92%) also reported that they felt more stable and tasks were easier to perform in the 13

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customized seating system (wheelchair). However the results could be the indicators of the familiarity of the subjects with the wheelchair, since 92% of the population who participated in the study was a current wheelchair user. 1.4.2.2 Quantitative Studies As Fisk mentioned in his work, all these studies have measured fatigue in a qualitative way and they do not normally include quantitative evaluations. There are others studies that have attempted to accomplish the quantitative analysis of fatigue. Provinciali et al. 34 utilized different tests, in order to analyze 6 disability domains in people with MS: timed 10 meter-walking test, the Nine Hole Peg Test13, card-sorting test, word fluency test, etc. The involved domains were: motor ability, cognitive performance, daily live activities, mood, handicap and quality of life. This study showed that more aspects were needed to evaluate the situation of people with MS. Frzovic et al.1 (2000) has studied standing balance in people with MS. The author performed 3 clinical tests : steady stance, self generated perturbation and external perturbation. The subjects were able to walk a distance of 14 meters, 3 times, without walking aids. The number of times the subjects could raise their hands during a period of 15 seconds was recorded. The test was performed twice in a day (I 0 a.m. and 3 p.m.) and only light activities were performed during the interval. The study concluded that there was no difference. Results showed that although patients reported feeling more fatigued in the afternoon than in the morning, their physical 14

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performance showed little change. There was no difference between MS and control groups on maintaining balance. However, people with MS performed more poorly than control subjects on the functional reach task. The study performed by Vollestand35 (1999) presented several methods to quantitatively measure human fatigue. He classified the methods into direct and indirect. In the direct method, he included maximal voluntary force generation of both upper and lower limbs, power output, tetanic force (independent force of the motor central drive) and low frequency fatigue. In the indirect one, he considered twitch interpolation, endurance time and electromyography (EMG). Electromyography (EM G) is a technique used to test the electrical activity of a skeletal muscle. An EMG is used to detect disorders that mainly affect the muscles It is also used to diagnose muscle problems caused by other diseases, stich as nerve dysfunction. Drory et al. 36 performed a surface EMG on the upper and lower limb muscles on people with and control subjects. The study showed that 80% of the MS patients had abnormal results for the EMG test. Yokota et al. 37 performed a comparison of control subjects, patients with spinal cord transection and people with MS. They performed EMG on both the palms and soles. The study showed that the results for 75% of people with MS were abnormal. Similar studies performed independently by Chen39 and Armstrong 40 They measured the knee muscle functions on control subjects and people with MS, using the Cyber II isokinetic dynamometer to measure the torque. The results showed that 15

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patients with MS, when compared with healthy subjects, exhibited mean torque velocity values that were significantly lower and yet had curves similar in shape to healthy subjects Most of the studies measuring fatigue have used qualitative measures, which are not exact indicators of fatigue due to the subjectivity of the methods and the confusion with other symptoms The quantitative methods used are related to forces, power, and muscle activity, but new measurements are still needed, no test has been able of separate the causes of fatigue objectively 16

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2. Hypothesis The hypotheses of the study were based on the observation of medical personnel on people with MS that use power mobility aids. These observations leaded to hypothesize that people with MS using non-customized seating systems on scooter bases would decrease their physical activity faster than using customized seating system on powered wheelchair bases because the latter ones provided a better basis of support for the subject's body As mentioned in section 1.2.4 1 the quantitative study33 performed on the present study supported this hypothesis. In order to measure the variation on the physical activity of the subject with MS on each seating system, a sequence of performance tests were used in the study. It was hypothesized that the overall performance of the test sequence in a customized seating system (wheelchair) is better than in a non-customized seating system (scooter). Performance was determined by the measures calculated on each task of the whole test. Since the customized seating system provides better basis of support, the subject's trunk and functionally dominant arm would be able to move further from the customized seating system compared to a non-customized seating system with a worse basis of support. 17

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For people with MS group the original specific hypotheses of the study based on the measurements performed were: 1. Because of the larger motion of the arm in the customized seating system, the total path length during the repeated upper extremity motion task will be longer in a custom seating system (wheelchair) compared to a non-customized seating system (scooter). 2. Due to the larger motion of the trunk in the customized seating system (wheelchair), there will be greater forward and lateral trunk flexion, measured as angles, than in a non-customized seating system (scooter). 3. Because of the larger combined movement of the trunk and functionally dominant arm on the customized seating system, the center of pressure (COP) trajectory of the body-seat interface will have a higher range of motion in a customized seating system (wheelchair) compared to a non-customized system (scooter). Regarding the comparison group, no differences were hypothesized between the performances on the two seating systems. It was thought that this group performance was not affected, as much as the performance of the people with MS group, by the two seating systems compared in the study. Since the performance of the people with MS was affected by the seating systems, it was hypothesized to be less than the performance of the comparison group. 18

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Figure 2.1 shows the levels of performance hypothesized corresponding for each case of group and seating system along the time. The comparison group will start from a higher level cPt) compared to the people with MS (Pz). No differences will be found on the comparison group. People with MS performance in the noncustomized seating system will decrease faster (P 4) compared to the performance in the customized seating system (P3). Performance ------------------I I I I --------I __ Jl: 1 I I I I I I I I I I I Comparison Group (Either Seating System) People with MS in Customized Seating System People with MS in Non Customized Seating System Time Figure 2.1. Hypothesized Performance Variation During Testing. 19

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3. Methodology The present research was conducted to investigate the influence of seating systems in people with MS on function A certificate of approval is shown in Appendix A. Quantitative assessment of performance using posture and reaching distance has been accomplished in several studies previously mentioned. However, the quantitative measurement of fatigue has not been well developed to date. There continues to be a need for additional, more effective measures Ten subjects with MS and ten healthy subjects were included in the study. The analyses of these two groups were performed in order to observe how the seating systems interacted with them and if they were differences. Testing was performed on a 10-degree tilted ramp with the subject's functionally dominant on the high side of the surface in order to increase the challenge on the individuals The test consisted on a sequence of tasks that included lateral and forward reaches, repetitive motion around to pegs following an elliptical path and, can stacking, a subtest from the Jebsen Test12. Angles of the test subject's body during the tasks, distances traversed, and center of pressure (COP) excursions were calculated from the collected data. The study consisted of the following tasks: 1 A sequence of tasks able to show the difference between the two motorized seating systems. 20

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2. A human body motion marker template, which allowed the calculation of parameters involved with the range of motion during the chosen tasks 3. Analysis of the results in order to determine and quantify the differences between the two motorized seating systems. 4. Analysis of the results in order to determine and quantify the differences between the comparison group and people with MS. 5. Selection of quantities that would express how users interacted with the seating systems. 3.1 Population: Comparison Group and Subjects with MS 3.1.1 Comparison Group Ten able-bodied healthy subjects, five males and five females, were used as reference for the study. The same manual wheelchair and powered scooter was used for each subject. Subjects were recruited based on their body size, so they would fit appropriately into the wheelchair and scooter provided. All participants in this group were of Caucasian with an average age of 41 years old and a standard deviation of 11.6 years. 3.1.2 Subjects with MS Subjects were recruited from the Multiple Sclerosis Clinic and Wheelchair Clinic at the Denver Veterans Affairs Medical Center (DV AMC), Physical Medicine & Rehabilitation Service. All participants received $50.00 US. 21

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In order to accomplish the inclusion criteria, all subjects with MS that participated in the study were using powered mobility provided by the DV AMC. The average age of this group was 56.4 years old with a deviation standard of 11.8 years old. Nine of the ten participants were Caucasian and one was African American. Individuals had trunk and upper limb mobility and they had a Kurtzke Scale rating between five and eight. The average value of the scale number was 7 05 0.98. This group had had MS for 17.1.2 years and they had been using mobility aids for 4.6 7 years. Eight of the ten subjects with MS included in the study had their own customized seating system on a powered wheelchair base. They had been measured and fitted by a seating specialist from the DV AMC in a power wheelchair. For these subjects, the same scooter with an off-the-shelf seating system was provided One subject used a motorized scooter as a primary mobility aid, so a customized seating system on a power wheelchair base was provided for testing. A trained physical therapy from the DV AMC went through to the procedure of measuring and fitting this wheelchair to make it customized to this person. The remaining subject used both a power wheelchair with a customized seating system and a scooter, which he owned. 22

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3.1.2.1 Consent Protocol Before preparing the subject for data collection, a consent form and protocols were reviewed privately with each subject. All participants signed an informed consent prior to initiating of testing This consent is included in Appendix B 3.1.2.2 Test Preparation Individuals with MS completed a demographic medical questionnaire, included in Appendix C This questionnaire was utilized to perform the subjective study33 Subjects also underwent a modified physical examination including range of motion measurements and manual muscle testing of the arms as well as anthropometric measurements before the test. Forms used in these exams are included in Appendix D 3.2 Test Equipment Two main systems were used during the test. A measurement motion analysis system working at a rate of 60 Hz was utilized to quantify the movement of the individuals during the test. In addition to that, the pressure distribution at the body seat interface was collected using a pressure mat working at 10 Hz. Detailed procedures for the use of these equipments are included in Appendix E The data collections of these two systems were started at the same time by using an electronic synchronizing trigger. The wiring diagram of this device is shown in Appendix F. 23

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3.2.1 Measurement Motion Analysis System The chosen measurement motion analysis system, manufactured by Peak Performance Technologies Inc, is based on reflective markers attached to the subject's bony protuberances in order to minimize the effect of the skin movement. Six digital cameras, working at 60 Hz, tracked the marker movements, using high definition video tapes (S-VHS). Nineteen spherical markers with a diameter of 0.054 m were used for testing; this marker set is shown in Fig. 3 .1. Reflective markers were placed on 16 anatomical landmarks, shown in Appendix G, using double-sided tape. A trained physical therapist located the markers by palpation. ..... ... I \ \ \ \ l Sl \ I IRK I \ \ \ RA ,,-,, s3 I \ \ \ \ ..... \ ....... ...., I I ... 1 \ S2 : I I I I \ I \ I \ I ... __ LA LLE LLW Marker Locations RAC: Right Acromium LAC: Left Acromium RGT: Right Greater Trochanter LGT: Left Greater Trochanter RLE: Right Lateral Elbow RME : Right Medial Elbow LLE: Left Lateral Elbow LME: Left Medial Elbow RL W: Right Lateral Wrist RMW: Right Medial Wrist LL W: Left Lateral Wrist LMW: Left Medial Wrist RK: Right Knee LK: Left Knee RA: Right Ankle LA: Left Ankle S 1: Axis Right End S2: Axis Left End S3: Back of the Seating System Figure 3.1. Marker Set. 24

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The other 3 makers were located on the seating system. Each marker was covered with reflective painting to make the data collection easier. In addition to the marker set presented, during the elliptical path task two small markerS were located at the ends of the pegs to identify their locations Videos, with the recorded trials, were uploaded into a computer using Peak Matus software. This software allowed identification of and tracking each marker on all frames during data collection This allowed three-dimensional data to be reconstructed and analyzed. Based on the location of each marker defined by the x, y and z coordinates, calculations of angles and distances were calculated. The location and orientation of all cameras were arranged such a way that each marker could be seen from at least two of the cameras at every moment. Once the desired positions were defined, cameras were secured with adhesive tape. Figure 3.2 shows the laboratory set-up for a right-handed person. Cameras were focused on the functionally dominant side: in case of Fig. 3 .2, three cameras were located on the right side, one attached to the ceiling and the two remaining ones were located on the left side. The space covered by all the cameras is represented in the figure as the green box. 25

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Figure 3.2. Laboratory Set Up for a Right-Handed Person. At the beginning of the test a calibration procedure was performed to define the location and orientation of the cameras with respect to the laboratory. This was completed using two different devices : 1. A 17-marker calibration frame: this was utilized in order to determine the exact relative position and orientation of each auxiliary camera with respect to the main camera location. A scheme of this frame is shown in Fig 3 3. 26

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I (j_) I I I Figure 3.3. Seventeen-Marker Calibration Frame 0.038 m All 17 markers must be seen in each camera. In order to accomplish this, the frame was moved or rotated around the vertical axis of the tripod supporting the frame. 2. A 3-marker frame: this device is used to locate the origin and orientation of the laboratory frame with respect to each camera involved A scheme is shown in Fig.3 .4. 27

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y 0 0254 m X 0.40m Figure 3.4. Laboratory Coordinate System Frame. Once all markers were seen in all of the six cameras, the views from those cameras were recorded for later upload. After this, the calibration devices were removed from the testing space The cameras remained at the same position and orientation during the rest of test. In order to reconstruct the 3-dimensional movement from 2-dimensional videos it is necessary to have all these videos synchronized. Since this is practically impossible to accomplish manually, the measurement motion system used has the ability to produce a signal, by pressing a button at the beginning of each task, which was sent to all cameras when the test was being performed. This signal is used to have all videos aligned. Since all the videos had different lengths, only the interval covered by all cameras was kept for the analysis This final version of the videos was recorded into the computer. Figure 3 5 shows how the video processing is performed. 28

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Tape 1 Tape3 Tape4 Tape5 Tape6 Cut Aligning Signal Video Interval Used Figure 3.5. Video Processing. 3.2.2 Force Sensitive Applications (FSA) System Cut A 16 x 16-inch FSA mat pressure containing 256 one-inch pressure sensors manufactured by Vista Medical was used to collect information about the pressure distribution on the body-seat interface Clinicians typically use mats to measure the effects of cushions and positions on interface pressures for people limited to a wheelchair for mobility Pressure distribution on the 256-sensor mat was collected at a rate of 10 Hz during the first 44.7 seconds of testing. All data was recorded into by a data logger system, and then downloaded into a computer with the FSA software Figure 2 6 shows the pressure distribution measured by the 256 sensors of a person from the comparison group. 29

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250 8 \ 225 c D lf 200 E 1,!,175 F H G 150 H I ./ 100 75 Sensors Included Variation coelllcient Standard deviation Average pressure Maximum pressure Center of pressure Figure 3.6. Pressure Distribution on the FSA Mat. 220 97.8% 48.4 49.5 250 10.9, 9.5 Based on the pressure distribution obtained from the mat, the FSA software evaluates the location of the center of pressure, the average and maximum pressures, the standard deviation, and the number of cells sensing pressures different from zero (active cells). The pressure mat had the disadvantage of creep. In order to take this into account, continuous pressure relieves or push-ups were performed every 5 minutes. 3.2.3 Synchronizing Device In order to have the data from the measurement motion analysis system and the pressure system synchronized, a trigger device was implemented Its wiring diagram is shown in Appendix F. This device allowed sending the same signal to the 30

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video controller and to start the pressure data collection on the mat. Figure 3. 7 shows a scheme of how the measurement motion and pressure systems where linked using the trigger. Only the equipment for camera 1 is shown in this case. Equipments corresponding to other cameras are similar to camera 1. Camera 1 S-VHS Recorder ToCamera2 ToCamera3 To Camera4 To Camera 5 ToCamera6 Video Mat Pressure Collection FSA Computer Figure 3. 7. Measurement Systems. 31

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Initially the FSA computer plug (A) is connected to the collection box in order to set the FSA system up. FSA is set up at the remote set-up mode. Once this system is ready, plug A is disconnected and the from the measurement motion system plug (B) is connected. Right before the task started, the trigger box button was pressed, starting the collection of pressure data and sending a signal to the video controller After completing the task, the plug B is disconnected and plug A is connected to let the FSA computer download and save all data from the corresponding task. 3.2.4 Tilted Surfaces In order to increase the challenge during testing, the tasks were performed on a wooden ramp. This ramp was tilted 10, with the subject's dominant side on the high side of the ramp. The seating system was parallel to the rise of slope of the ramp. Seating systems were secured to the main wooden surface using tie lock downs. An antiskid path underneath these surfaces was used to prevent any displacement. For the comparison group, the seating systems were placed on the ramp, locked, and then the subject easily sat down. The subjects with MS were placed in the desired seating system and they drove onto the ramp using auxiliary ramps. The auxiliary ramps were located at the front and back of the main ramp They were attached to main ramp by screws. These three surfaces are shown in Fig. 3.8. The specifications of all the ramps are included in Appendix H. 32

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....----47.5" Figure 3.8. Tilted Surfaces. Figure 3.9 shows the tilted surfaces assembled together with a power wheelchair on top of them. The orientation shown corresponds to a right-handed person. As mention before, the seating system was aligned with the rise of the slope. The arrows show the way the seating system was driven in order to get up and down to the surfaces. Figure 3.9. Seating System Location on the Tilted Surface. 33

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3.2.5 Peg Holders For the elliptical path task a pair of peg holders were built. One holder is shown in Fig. 3.10 and the specifications are included in Appendix I. The location of the reflective marker was vertically variable since it had to adjust to the size of the subjects In order to do that an outside threaded bar was attached to the end of the horizontal bar 8' 8' Reflective Marker Figure 3.10. Peg Holder .. 6' Peg These holders were 8 feet tall and held the markers from above in order to avoid blocking the markers from the camera's views. A reflective marker was located 34

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at the end of each peg in order to locate this position with respect to the subject's movement 3.2.6 Other Tools A height-variable table, a stop-watched, and five empty soda cans were utilized for the can stacking portion of the test Additionally, a tape measure, a lever, a goniometer, and a small peg were used too. The lever was used for setting the markers of the holders at the same level as the subject's dominant side shoulder. 3.3 Test Description Comparison subjects and subjects with MS perfonned the same task sequence on each of the seating systems. The order of placement in the seating system was randomized for each subject. 3.3.1 Previous Set Up The measurement motion system was calibrated at the beginning of the test for each subject. After that the ramps were located and oriented according to the handedness of the subject. If comparison subjects were being tested, the seating system on its power base was secured on the tilted surface; the pressure mat was located on the cushion and finally the subject was seated If subjects with MS were tested, the pressure mat was located on the cushion and the subject was seated in that seating system while on the flat surface. The subject then drove up on to the tilted surface, where they power base was secured on the ramp 35

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3.3.2 Sequence of Tasks The following is the sequence of tasks used in the experiment. Individuals performed this sequence twice : once sitting in the customized seating system on a power wheelchair base and once in the offthe-shelf seating system of the scooter 3.3.2.1 Initial Lateral and Forward Reaching Task Individuals were asked to perform a forward and lateral reaching using their functionally dominant hand Before this task, subjects were asked to rate their fatigue and perceived exertion using the form included in Appendix C in order to perform the subjective study33. A set of five maximum reaches was completed Subjects were looking at a target placed on the wall at eye level in each direction They were asked to remain sitting without using the non-dominant arm to hold on to the seat, placing their non-dominant hand on their thigh. After each reach they were asked to return to the original position, touch their thigh and then start another reach cycle They were provided a command to start at the beginning of the reaching task and a command to stop at the end of the five cycles Consistent instructions were given to each subject. Figure 3 .11 shows a frontal view of a right-handed subject performing a lateral reaching task having a visual target. The initial and the maximum reaching positions are shown 36

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Visual Target Eye Leve Height Figure 3.11. Frontal View ofLateral Reaching Task for aRight-Handed Individual. Figure 3.12 shows a lateral view of a right-handed subject performing a frontal reaching task. The initial and the maximum reaching positions are shown As well as the lateral reach, there was a visual target located on the wall 37

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ye Level Height Visual Target Figure 3.12. Lateral View of Frontal Reaching Task for a Right-Handed Individual. 3.3.2.2 Elliptical Path Task This task consisted on thirty circular motions around a target marker placed at the subject's arm length directly in front of the functionally dominant hand and another target at 45 degrees laterally to the functionally dominant side. Motion will be in a counter clockwise direction for people using the right hand and clockwise for those left hand functionally dominant. Individuals used their functionally dominant 38

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hands to go around the target markers holding a small rod in that hand. The locations of the markers are shown in Fig. 3.13. Seating System Shoulder Height Lo: distance from the acromium to the end of the middle fingertip (a) Top View (b) Front View Figure 3.13. Peg Locations for a Right-Handed Person. The subjects were provided a command to start at the beginning of the elliptical path, every five repetitions were counted off and a command to stop at the end of the thirty cycles was given. Consistent instructions were given to each subject. 39

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3.3.2.3 Can Stacking Task Using a sub-test from the Jebsen Test12, five empty soda cans were placed on a table in front of the seated subject and the subject was asked to place each of the cans onto a raised surface on the table. This raised surface was 3.5 inches above the table surface stacked onto a raised board. The time it took the subject to complete the can sacking was recorded. Consistent instructions were given to each subject. The arrangement of the cans with respect to the table is shown in Fig.3.14. 4" Figure 3.14. Can Stacking Test Arrangement. 3.3.2.4 Final Lateral And Forward Reaching Task The lateral and forward reaching task was repeated as described in section 3.3.2.1. This task was performed In order to observe differences at the beginning and the end of the test. At the end of this task, subjects were asked to rate their perceived exertion and fatigue the same way they did before the initial reaching task. 40

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3.3.3 Time Sequence In order to have standardized the completion time of the test for subjects with MS, a time sequence was established. Initially subjects were seated for 5 minutes and then performed a weight-relieving push-up. After waiting for 5 minutes, the lateral and forward reaching task was performed. Immediately after this task, another weight-relieving push-up was performed and after another five-minute period a new weight-relieving push-up was performed. The elliptical path task was performed after waiting for 5 minutes Two other weight-relieving push-ups with their respective five minute periods were performed before the completing the stacking can task. Two final weight-relieving push-ups and two five-minute periods were performed before the final lateral and forward reaching task was completed. Assuming one minute per each lateral and forward reaching task, two minutes per elliptical path task, and one minute per the stacking can task, the total test time per seating system was 45 minutes. Periods between each task allowed testers to get all systems ready to collect. If for any reason, a system did not work at the beginning of the task, subjects were asked to stop and they performed a push-up at that moment and another 5-minute period was waited before redoing the task. The time sequence is shown in Fig.3.15. The comparison group had only one push-up and one five-minute period before every single task. 41

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Weight-Relieving Push-Up Elliptical Path Task Lateral and Forward Reaching Task Can Stacking Task n ; II il Ill j. El El Ill lA If 5 5 1 5 5 2 ---.. 5 5 I 5 5 1 Figure 3.15. Time Sequence (minutes). 3.3.4 Randomization and Resting Procedure The test sequence was repeated in the customized and the non-customized seating system in a randomized way. This was accomplished by picking the first seating system, and the others were chosen alternatively. 42

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A 30-minute rest period was given to the subjects between testing in the two seating systems. Depending on which seating system was tested first the structure of the resting period was chosen If the current or familiar mobility aid used by the patient was tested first, subjects rested for the next twenty minutes in their own seating system Ten minutes prior to the beginning of the test in the non-familiar seating system, subjects were transferred to this seating system During this period, subjects performed some reaching and range of motion movements in order to become familiar with the new seating system. If the non-familiar seating system was tested first, reaching and range of motion movements I 0 minutes before starting the test. Subjects were transferred to the familiar seating system as soon as the test is completed on the non-familiar seating system. The resting period is then performed on the familiar seating system. 3.4 Test Conditions For subjects with MS population, the room temperature was kept between 68 and 70F using and air conditioning system During rest periods the lights from the cameras were turn off in order to minimize the heat radiation coming from the lights. 43

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4. Data Analysis 4.1 Coordinate Systems In order to perform all the biomechanical calculations different reference Cartesian coordinate systems were defined. These coordinate systems were based on the laboratory, the seating systems and the trunk of the subjects. 4.1.1 Laboratory Coordinate System The 3-marker calibration frame defined this coordinate system. It was located in front of the 17 -marker frame (section 3 .2.1) at the floor level during the calibration process. The orientation of this coordinate system was not the same for all subjects because of the necessity of rotating the frame in order to have the markers on all of the camera's views during calibration. Due to the direction of the XL and Y L axes, the ZL axis was always pointing upwards to the ceiling of the laboratory. All data from the human motion analysis system used this coordinate system as a reference. Figure 4.1 shows the orientation of the laboratory coordinate system with respect to the 3-marker calibration frame. Axes XL and Y L were located at floor level. 44

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Figure 4.1. Laboratory Frame Reference. 4.1.2 Seating Coordinate System The seating coordinate system was based on the markers located on the seating system tested: Xss, Yss and Zss, where the subscript SS refers to the seating system This coordinate system was attached to the seating system. Figure 4.2 shows the coordinate system rotations in order to get from the laboratory to the seating system coordinate. Initially there was a rotation of e1 about the ZL axis to align Y L to the frontal direction of the seating system (Fig 4.2a), creating the coordinate system XAYAZA, where the subscript A stands for auxiliary coordinate system. The value of e1 depended on each subject The second rotation of e2 was about the Y A axis, which allowed XA to be parallel to the axis ofthe seating system (Fig. 4.2b) The values for e2 were very to I 0 for all subjects. 45

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(a) Rotation around the ZL axis (b) Rotation around the Y A axis Figure 4.2. Coordinate System Rotations. Three markers placed on the seating system were used to determine this coordinate system In order to facilitate the data collection, two of the markers (S1 and S2 ) were placed at the two ends of the main axis and the remaining one (S3) was placed at the back of the seating Figure 4.3 shows a usual location ofthe markers on a seating system. If the seating system were placed on a flat surface, the Z-axes of the auxiliary and the seating coordinate systems were the same (Fig. 4 3a). However, since the test was performed on a tilted surface, the orientation of the seating coordinate system was differen t (Fig. 4 3b). Even though the Y-axis was the same, axes XL and ZL were deviated 10 from their corresponding axes in the auxiliary coordinate system 46

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Xss (a) On Flat Surface. -------,.--. __ -...... 100 -----(b) On Titled Surface Figure 4.3. Seating Coordinate System The locations of S1 and S2 with respect to the origin of the laboratory coordinate system were expressed as the vectors S1 and S2 The vector that comes from the left end to the right end of the axis was defined as follows. (4 1) Using the other marker location, S3 it is possible to define another vector. 47

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(4.2) In addition to these two vectors, another vector was defined as the cross product of the two previous vectors, which creates the vector R = P x Q (4.3) Figure 4 4 shows the direction and orientation of these vectors with respect to the laboratory coordinate system The vector R is perpendicular to the vectors P and Q since it is the result of the cross product of them Figure 4.4. Vectors P, Q, and R attached to the Seating System Even though these three vectors are not perpendicular between them and they are no unit vectors, they constituted a base since they are non-dependant, so any other vector can be expressed as a linear combination of them as follows V = aR + bP + cQ, where a, b, and c are scalars (4 4) The unit vector K ss can also be expressed as this combination as 48

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(4.5) This expression is truly independent from the coordinate system and from the orientation that the seating system had In other words, the scalars aK, bK, and CK will be independent if the seating system was on a flat or tilted surface. If the seating system remains on a flat surface the vector K ss will be parallel to the positive vertical direction, this is: Kss =[ 0 0 1 ]' (4.6) From the previous expression it is possible to rewrite in a matrix form: K,. =aP+bQ+cR=[P Q Rm (4 7) m12 m13 ][OJ [m13 ] m22 m23 0 = m23 Finally the scalars quantities are: m32 m33 1 m33 (4.8i) b=m23 (4 8ii) (4.8iii) In order to assume the vector K ss in the vertical direction it was necessary to obtain the locations of S1, S2, and S3 when the seating system was on a flat surface 49

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This procedure was done at the end of the test. Once the unit vector K ss was determined, the unit vector parallel to the y-axis, J ss, was obtained. J = Kss xP ss I A I KssXP (4.9) Finally, the unit vector parallel to the x-axis is calculated iss = J ss x K ss (4 10) The origin of this coordinate system was considered as the right end of the seating system axis (St). 4.1.3 Auxiliary Coordinate System In order to compare the trajectories of the wrist during the forward and lateral reaching and the elliptical path tasks, the auxiliary coordinate system was used. As explained in section 4.1 2, this frame was oqtained by a rotation about the Z-axis of the laboratory coordinate seating system (ZL). As shown in Fig. 4 .5, the origin of this system was located at the midpoint of the line that jointed the two greater trochanters of the subject tested at the beginning of the test. --._1 Xss Figure 4.5. Auxiliary Coordinate System. 50

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The unit vectors for this coordinate system were obtained as follows. The z axis unit vector was the same as the corresponding to the laboratory. (4.11) The Y -axis unit vector was the same as the corresponding to the seating coordinate system. (4.12) Finally, the X-axis was determined by the cross product of the two previous unit vectors. (4.13) 4.2 Reduced Marker Set The original marker set for this study used 17 markers located on the subject's body. However, in order to perform the calculations, other locations were needed. The motion measurement system used had the ability to calculate locations based on the locations of the markers. For this study, the calculated midpoints of the upper limbs and trunk segments where considered as joint centers. These joint center locations were the following: 1. Midpoint of the line that jointed the markers on both acromium markers (right and left acromiums). This location was denoted as MA 2. Midpoint of the line that jointed the markers on greater trochanters (right and left greater trochanter). This location was denoted as MGT. 51

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3. Midpoint of the lines that jointed the markers on the medial and lateral side of the elbows. There were two locations in this case: right elbow (RE) and left elbow (LE). 4 Midpoint of the lines that jointed the markers on the medial and lateral side of the wrists. There were two locations in this case: right wrist (RW) and left wrist (LW). In order to perform the analysis and calculations the calculated joint centers and some of the marker locations are needed. Those locations are shown in Fig. 4 6 Marker locations are shown in black ( ) and joint center locations in white ( o ). RAC LGT LAC ,LK I I I I I I I 'LA ') .... ___ Locations LAC: Left Acromium RAC: Right Acromium MAC: Mid Acromium LGT: Left Greater Trochanter RGT: Right Greater Trochanter MGT: Greater Trochanter RE: Right Elbow LE: Left Elbow RW: Right Wrist LW: Left Wrist RK: Right Knee LK: Left Knee RW: Right Ankle LW: Left Ankle Figure 4.6. Marker Set Locations ( ) and Calculated Joint Centers ( o ). 52

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4.3 Vector and Matrix Descriptions In order to express the calculated quantities in terms of the reference coordinate systems presented before, some techniques commonly used in the robotics field were used. These techniques involved matrix operations and some modifications to the original vectors The purpose of using these formats is to make the equations more compact and to have more efficient computer programs. 4.3.1 Vector Notation A vector coming from the origin to a location M expressed in frame A is expressed as A PM Equation 4.14 shows the corresponding format used for the vector. (4.14) 4.3.2 Matrix Operators In order to express the same vector with respect to different frames it was necessary to use an operator that involved the translation and rotation required to get from one frame to another frame. 4.3.2.1 Translation If the vector M, expressed in frame A as A PM needed to be expressed in a frame B, which is parallel to frame A, a vector addition was performed to obtain (4.15) Where A P8ong was the vector of the origin of the B frame expressed in frame A 53

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. 4.3.2.2 Rotation Another case of coordinate system transformation was when the vector M, expressed in frame A as A PM needed to be expressed in frame B, which had the same origin as A but different orientation. The vector M expressed in frame B as 8 PM was related to A PM following (4.16) Where ;R is a 3x3 matrix called rotation matrix that describes frame B from frame (4.17) quantities A l 8 A J 8 and A K 8 are the unit vectors of frame B expressed in frame A 4.3.2.3 Translation and Rotation The most general case would be when a translation and a rotation were present during the transformation. For example if the vector M, expressed as A PM with respect to :frame A, needs to be expressed with respect to frame B, as 8 PM the equation that related those two quantities is: (4 18) where is the description of frame B with respect to B, a 4x4 matrix operator defined as (4 19) where ; R is rotation matrix that express frame B in frame B and A P80,;g is the vector of the origin of the B frame expressed in frame A 54

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4.4 Calculations Based on the reduced marker set, various quantities were calculated. These quantities were focused on the trunk and the subject's functionally dominant side wrist. The motion measurement analysis provided the x, y, and z coordinates of every marker with respect to the laboratory coordinate system. 4.4.1 Trunk Excursion Measurement of trunk excursion was based on the markers located at the acromiums and at the greater trochanters. The trunk was idealized as the line that joins the mid-acromium (MAC) and the mid-greater trochanter (MGT). Figure 4 7 shows the markers and joint center locations used for this segment. MAC LAC RGT e-------a LGT MGT Figure 4.7. Locations Involved on Defining the Trunk The trunk vector, expressed in the laboratory coordinate system from the mid greater trochanter, L PMGT, to the mid-acromium, L PMAc, was defined as: 55

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L p trunk =L p MAC _L PMGT (4.20) The trunk excursion was measured as the maximum and the average of the excursion angles and the distance from MAC to MGT In order to measure the excursion angles it was necessary to measure the orientation of the trunk vector with respect to the coordinate seating system For these calculations the trunk vector was considered as a free vector. Equation ( 4 .16) was used to relate these quantities. Lp LR ssp trunk = ss trunk (4 21) ssP trunk was the trunk vector expressed in the seating coordinate system, and s: R was the rotation matrix between the seating and the laboratory coordinate systems. This rotation matrix was defined based on the unit vectors of the seating coordinate system as L [i A A ] ssR = ss Jss Kss (4.22) From Equation (4 21) the vector ss Prrunk was calculated as : ssp ( LR)-1 Lp [ss ssy ssz 1], trunk = ss trunk = xtrunk trunk trunk (4.23) These quantities are shown in Fig 4.8 where the free trunk vector has been moved to the origin to the seating coordinate system The coordinates 88Xtnmk, 88ytrunk, and ssZtrunk are shown in the scheme as well as the angles involved measuring trunk excursiOn. 56

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Yss Figure 4.8. Trunk Vector Expressed in the Seating Coordinate System. 4.4.1.1 Flexion/Extension Trunk Angle This angle is measured on a plane parallel to a plane formed by the Y -axis and Z-axis of the seating system, which corresponds to the sagittal plane. Figure 4.9 shows how this angle is defined by the projection of the trunk vector (from MGT to MAC) on the plane described before and the axis Zss. This angle is denoted by a: (4.24) 57

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Z'ss Zss Xss MAC' ) \ ss Ztrunk Y'ss Figure 4.9. Flexion/Extension Trunk Angle 4.4.1.2 Lateral Flexion/Extension Trunk Angle This angle is measured on a plane parallel to a plane formed by the X-axis and Z-axis of the seating system, which corresponds to the frontal plane. Figure 4.10 shows how this angle is defined by the projection of the trunk vector on the plane described before and the axis Zss. This angle is denoted by p. (ssx ) p = tan -I ss trunk ztrunk (4.25) 58

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J Zss MAC" I -.. .... --... ,.,,--.. -................................ .. .. "' J Xss Figure 4.10. Lateral Flexion/Extension Trunk Angle. 4.4.1.3 Trunk Length In addition to the previous angles defined the distance between the MAC and the MGT was measured in order to see if the trunk was expanding or contracting during the trials. This distance was calculated as the length of the trunk vector. (4 26) 4.4.2 Wrist Trajectory The analysis of the wrist trajectory was based on the location of the functionally dominant wrist. In order to visualize the trajectory of each individual, the trajectory of this location was calculated with respect to auxiliary coordinate system 59

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explained in section 4 .1.3. To obtain the coordinates with respect to that frame, the following matrix equation was used. (4.27) The location of the wrist, given by the human motion system was L P wnst the transformation matrix, and A P wrist was the location of the wrist with respect to the auxiliary coordinate system The transformation matrix was obtained from the unit vectors corresponding to the auxiliary coordinate system as follows: KAL A ] 0 PMGTO (4.28) The quantity L P MGTo is the location of the midpoint of the greater trochanters location at the beginning of the task Finally, from the equation 4.21, the location of the wrist with respect to the auxiliary system was calculated as: (4 29) 4.4.2.1 Path Length The calculation of the path length during a g1ven task is based on the summation of the linear distances between two consecutive locations of the wrist. Figure 4.11 shows two consecutives locations of the wrist during a given task: (APwrist)i+l and (APwrist)i are the locations of the wrist at frames i and i+ 1. 60

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--/ / / / _,-' "'(APwnst)i+I 'Trajectory of the wrist Figure 4.11. Distance between to Consecutive Locations. The length between 2 points was approximated to ALi, which was calculated as following. (4.30) Equation 4.24 now can be written as: (4.31) Then the summation of all lengths becomes the total path length, this is: (4.32) Where N is the number of frames obtained from the human motion analysis. 61

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4.4.2.2 Determination of Cycles during the Elliptical Path Task In order to perform the analysis of the path length per cycle during the elliptical path test, it was necessary to determine the beginning and the end of every cycle. Figure 4.12 shows how these two instants were determined; the horizontal line that joints the two markers located at the end of the pegs was used as reference. The beginning and the end of each cycle occurred when the projection on a horizontal plane of the wrist location crossed that line. End: Frarnej Figure 4.12. Determination of the Duration of the Cycles. If the cycle started at frame j and ended at frame k, the path length corresponding to this cycle was obtained using 62 k Lcycle = L /1Li i=j (4.33)

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4.4.2.3 Reaching Ratio for the Lateral and Forward Reaching Task Another quantity based on the wrist location was the reaching distance during the lateral and forward reaching task. In order to perform the analysis of this measure the arm length was defined as the summation of the lengths corresponding to the arm and the forearm. The length hand was not included since the marker set utilized did not use any markers on the fingers The arm was defined as the segment from the acromium to the elbow and the forearm as the segment from the elbow to the wrist. Equation 4.34 shows how the arm length was calculated for a right-handed person using the coordinated from the laboratory system. La = IL PRAc_LpREI+IL pRE_LpRwl (4.34) Where RAC is the right acromium location, RE the right elbow location, and R W the right wrist location. Since this quantity was evaluated for every single instant there was a minimum variation on its value. An average value was considered for the ratio calculations. 4.4.2.3.1 Lateral Reaching Ratio The lateral reaching distance is defined as the difference between the maximum lateral reaching distance and the arm length. Figure 4.13 shows how this distance was measured with respect to the wrist location, when a right-handed individual performed a lateral reaching 63

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Lateral Reaching Distance Arm Length (La) RE _.,+----to,.._ Maximum Figure 4.13. Lateral Reaching Distance for a Right-Handed Subject. The lateral reaching distance (LRD) in this case was defined as: LRD =Maximum Lateral Distance -La (4.35) In order to compare the results from different persons, the lateral reaching ratio was defmed as the quotient of the lateral reaching distance over the arm length. Lateral Reaching Ratio = LRR = LRD La 64 (4.36)

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4.4.2.3.2 Forward Reaching Ratio The forward reaching distance was defined as the difference between the maximum forward reaching distance and the arm length. Figure 4.14 shows how this distance was measured with respect to the wrist location, when a right-handed individual performed a forward reaching. Ann Length /'... (La) I I I I I '.a:o-:' RAe ",, ,': \ ......................... I I 1 : I I liRE I--\ \ ... ) 'v ,,.,""' RW \ 'i ---\ _..t----.... 'I \ Beginning: Frnmek Distance Figure 4.14. Forward Reaching Distance for a Right-Handed Subject. The forward reaching distance (FRD) in this case was defined as follows. FRD =Maximum Forward Distance -La (4 37) 65

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The forward reaching ratio was defined as the quotient of the lateral reaching distance over the arm length. Forward Reaching Ratio = = -La 4.4.2.4 Vertical Distance from Acromium to Wrist (4.38) This quantity was calculated in order to measure how subjects kept the wrist height with respect to the acromium level. Figure 4.15 shows the scheme of how this distance was calculated for a right-handed person. ,---..... "' ... I \ \ I \ I I \ \ I A RA\._., ........ ___ ., I _.. .. ---.... I ....... ,,.--------............ <' A ,.-I \ .... WE ------RE \ ...... LAC \ \ \ I I I I I I I "MGT Figure 4.15. Vertical Distance from Acromium to Wrist. The locations of the corresponding acromium and wrist were considered to calculate the distance as follows: ( L L ) A d AW = pacromiump wrist K L (4 39) 66

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4.4.3 Posture The analysis of posture was performed by measuring angles relative to the position of the main segments of the body. For the analysis, the mid acromium (MAC) and the mid greater trochanter (MGT) were the considered locations. In addition to those locations, two new ones were defined to analyze posture: the midpoint to the line that jointed the two knee locations (MK) and the midpoint to the line that jointed the two ankle locations (MA). Figure 4.16 shows the scheme of the template utilized to measure posture: trunk-leg and knee angles. MAC MGT MA Figure 4.16. Posture Angles. 67

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4.4.3.1 Trunk-Leg Angle This angle is based on the locations of the mid acromium (MAC), mid greater trochanter (MGT), and the midpoint of the knee locations (MK). The expression to evaluate this angle was: (4.40) 4.4.3.2 Knee Angle This angle is based on the locations of the mid greater trochanter (MGT), the midpoint of the knee locations (MK), and the midpoint of the ankle locations (MA). The expression to evaluate this angle was: (4.41) 4.4.3.3 Leg Deviation Angle Another measures to analyze posture were the leg deviation angles. These angles were measured on a horizontal plane between the projection of the leg segments and the Y-axis of the seating coordinate system. Figure 4.17 shows the angles 81 and 82, measured between the projections of the legs and the Y-axis direction (represented as the dashed line). The results ofthis analysis were presented with respect to the functionally dominant side since the reaches were in that direction. A positive angle deviation for the dominant side leg indicates that the leg is deviating 68

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towards the dominant side and a positive angle deviation for the non-dominant side indicates that the leg is deviating towards the non-dominant side as shown in Fig. 4 .17. \ e1. \ I \ I \,6----! LK' I 82 i I I 'RK' I (-r) (-) (-) (-r) I I I I I I I I I I I I RGT' Figure 4.17. Leg Deviation Angles The equations to evaluate these angles were: (} -I((LpLK_LpLGT).jSSJ I -COS II II L pLK_LpLGT (4.42) (4.43) 4.4.4 Center of Pressure (COP) Based on the pressure distribution data collected by the FSA system, its software was able to calculate the location of the center of pressure during the tasks If t represents the time when the data was collected, A the area of each single cell (1in2), i the number of the cell that goes from 1 to 256, and P(l.O the pressure at that cell, the total force P at that time was calculated as: 69

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256 256 = L (p(t,i) A) = A. L P(t,i) i=l i=l The coordinates of the center pressure were calculated as: 256 L Xct.i) P(t.i) (xCOP )(t) = -'-i=....:...l -::-:25:-:-6 --LPct,i) i=l 256 LY(t,i) .p(t,i) (y COP )(t) = ...:..i=...:.l_25_6 --Lp(t,i) i=i Where x(i,t) and y (i.t) are the locations of the cell i at time t (4.44) (4.45) (4.46) Figure 4 .18 shows the orientation ofthe x andy axes on the pressure mat with respect to a right-handed person. p .... ,... .... LK ,,.' RK ,,."' : ,' I I I I I I I I I I I I .RA Figure 4.18. Resultant Force and Center of Pressure Location on the FSA Mat. 70

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4.4.4.1 COP Displacement This measure was performed to appreciate how the COP moved from its initial location The COP displacement was measured in two directions : frontal and lateral. For a right-handed person the equations were : (4.47) Frontal: 6{y coP )(t) = {y coP )(t) -{y coP )(o) (4.48) As well as the angle measures, the average of the COP displacement will be utilized for comparison (4.49) tN L (6YcoP )(t) A_:_t=..:..O ___ aYcoP =(4.50) N Where N was number of instants that the FSA system collected. In case a lefthanded person was tested, the directions of the axes were rotated 90 about the z-axis and the lateral direction became the y direction and the frontal direction was corresponding to the x direction. 4.4.4.2 Root Mean Square (RMS) of the Cop Displacement Another quantity to measure the excursion of the COP is the RMS of the COP displacement. This measure is related to the amplitude of the movement on each 71

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direction and it measures how far subjects move from the average location. RMS is also related to the absolute value of the area between the curve and its average value. Figure 4.19 shows graphs of two centers of pressure locations that have the same average value. However the case (a) shows less amplitude and less area than case (b), then case (a) will have a smaller value of the RMS compared to case (b). (a) (b) Figure 4.19. Root Mean Square of the COP Displacement. For a right-handed person the expressions are: Lateral_ RMS = LRMs = N (4.51) t COP )(t) -fly COP r Frontal_ RMS = F RMS = t=O (4.52) N Again, if the person tested was left handed, the LRMs was associated to the y-axis and the F RMS was associated to the x-axis. 72

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4.5 Statistical Analysis All data distributions were examined for normalicy, variables that did not have an absolute value of skewness greater than 1 were deemed to be not normally distributed. As sample size was small (n=10 per group), it was decided not to do transformations and chose to use non-parametric statistics for those relevant analyses. Any variables with outliers were examined to ensure that the number was a true entity and not a mathematical error. Parametric and non-parametric statistics were used to find significant differences based upon their distribution. Parametric tests (student t-test) were done when data was normally distributed and non-parametric (Wilcoxon) tests were done when data was not normally distributed. The p-value was set at an alpha of 0.1, a priori. Paired t-tests were used to compare the performance of the same group in the scooter and the wheelchair. Also, t-tests were used to compare the performance of the groups within the same seating systems All analysis was completed using the SPSS software. Measurements from the wheelchair and scooter were compared for all variables of interest (Trunk excursion, path length, reaching ratios, posture angles and COP movement). 4.5.1 Comparison of Seating Systems This comparison tests were performed in order to observe differences between the performances in the wheelchair and scooter. Each measurement during the initial 73

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reaching task was compared to the performance during the final reaching task in the same seating system to observe the variation along the test on that seating system. The measurements from both seating systems during the initial reaching tasks were compared to see the differences at the beginning of the test. Similarly, the measurements from both seating systems during the final reaching tasks were compared to see the differences at the end of the test. In total, four comparisons were performed from the reaching tasks. Measurements obtained from the elliptical path task and the completion time from the can stacking task in the wheelchair were compared to the results from the scooter. Figure 4.20 shows the comparison tests performed for the measurements involved. Wheelchair Scooter Initial Reaching Initial Reaching Task Results Task Results Elliptical Path Elliptical Path Task Results Task Results I Can Stacking I I Can Stacking Task Results ..... : Task Results I I Final Reaching : Task Results 1 I I Final Reaching Task Results Figure 4.20. Tests Performed for the Seating System Comparison. Arrows indicate the Comparison Performed. The comparison test results of the measurements path length, trunk excursion and COP movement were used to accept or reject the hypothesis presented before in Chapter2. 74

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4.5.2 Comparison of Groups In order to compare the performances .of the two groups, data from the same task and the same seating system was compared. Figure 4.21 shows how the comparisons were performed. Comparison Group Subjects with MS Wheelchair Wheelchair I I Initial Reaching : Initial Reaching Task Results Task Results Elliptical Path Task Results Elliptical Path Task Results Can Stacking Task Results Final Reaching Task Results I I ----------------Scooter I Initial Reaching : I Task Results Elliptical Path Task Results Can Stacking Task Results I I Can Stacking .Task Results Final Reaching Task Results ----------------Scooter Initial Reaching Task Results Elliptical Path Task Results Can Stacking Task Results Final Reaching Final Reaching Task Results Task Results ----------------I I ----------------------------------------Figure 4.21. Tests Performed for the Group Comparison. Arrows indicate the Comparison Performed. 75

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4.5.3 Order Performed Comparison The final comparison was performed in order to see if there was any learning effect, this is an increase on performance, on any of the groups because of repeating the same test on the second seating system tested. This comparison test was made in a similar manner as the seating system comparison. However, since the order of testing the wheelchair and the scooter was randomized, the first seating system could have been the wheelchair or the scooter. Figure 4.22 shows how this comparison test was performed. First Seating System Tested Second Seating System Tested Initial Reaching Initial Reaching .----r---i Task Results Task Results ..-----, Elliptical Path Task Results Elliptical Path Task Results I Can Stacking I I Can Stacking Task Results """4..-4------t-: ....... Task Results I I Final Reaching : Final Reaching ,___,.....-i Task Results Task Results I I ---------------------Figure 4.22. Tests Performed for the Order Performed Comparison. Arrows indicate the Comparison Performed. 4.5.4 Correlation Analysis In addition to the comparison tests performed correlation tests were ran to observe if there was a correlation between the measurements obtained from the tests. 76

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The minimum value for the correlation coefficient to consider a correlation was set equal to 0.6. The pairs of variables analyzed for correlation were the following: 1. Path Length and Trunk-Leg Angle 2 Path Length and Knee Angle 3. Path Length and Dominant Angle Deviation 4. Path Length and Non-Dominant Angle Deviation 5. Frontal COP RMS and Dominant Angle Deviation 6. Frontal COP RMS and Non-Dominant Angle Deviation 7. Lateral COP RMS and Dominant Angle Deviation 8. Lateral COP RMS and Non-Dominant Angle Deviation 9. Frontal COP RMS and Path Length 10. Lateral COP RMS and Path Length 11. Frontal COP RMS and Knee Angle 12 Frontal COP RMS and Trunk-Leg Angle 13. Lateral COP RMS and Knee Angle 14. Lateral COP RMS and Trunk-Leg Angle 77

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5. Results This chapter initially shows the results of specific individuals as examples After that, a summary of all results is presented, including the results from the comparison of mean tests. Finally, analyses of the path length variation along the time and can stacking completion time are presented. 5.1 Result Examples Examples of the results from the same subjects are presented in order to appreciate the behavior of the calculated measurements during the duration of the tasks included in the test. They are presented following the order established in chapter 4: trunk excursion, wrist trajectory, posture, and COP movement results. 5.1.1 Trunk Excursion Results Results from the calculation of the angles of a right-handed person with MS during the lateral and forward reaching task in the wheelchair are shown in Fig. 5 .1. Results from other subjects and seating systems did not show major difference with respect to this case, so only the results from one case are shown. A positive value of the angle meant a trunk movement in the forward or right direction. The lateral flexion/extension trunk angle increased initially due to the lateral reaching while the flexion/extension trunk angle had a minimum variation. The opposite occurs in the next instants, when a forward reaching was performed, the flexion/extension angle 78

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had more variation than the lateral flexion/extension. This sequence is repeated 5 times since the reaching set was completed five times. Figure 5.1 shows an initial value of -10 for the lateral flexion/extension trunk angle, which meant that the subject was laying the trunk on the seatback if the seating system. The maximum value corresponding to this angle was 30, when the subject was performing the second forward reaching. The initial value for the lateral flexion/extension trunk angle was 10, since the angle was referred to the seating system (tilted on a 10-degree surface); this meant that the subject kept the trunk in a vertical position. From the second forward reach, the subject kept the balance by moving the trunk to the left. The maximum value for this angle was 35.T during the last lateral reach. 60 50 -Flexion/Extension Trunk Angle 40 -Lateral Flexion/Extension Trunk Angle ,....., 30 '-' 20 c < 10 0 -10 -20 0 10 20 30 40 50 60 Time (s) Figure 5.1. Trunk Excursion Angles During Lateral and Forward Reaching Task for a Subject with MS in the Wheelchair. 79

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Figure 5.2 shows the variation of the trunk length during the lateral and forward reaching task for the same subject with MS. The initial value is equal to 0.492 m and the maximum value was 0. 725 m when the lateral reaching is performed. During the forward reach the maximum length was equal to 0.601. After each reach this quantity returned to its original value. ,...-.. ,, Cl) 0 fa -til i5 1 0.8 0.6 0.4 0.2 0 ' ::_:::_::::r::::::::::r::: -_: ::::::::::r:_---:-::1::::::::::--<:::::::::::r ::::::: 0 10 20 30 40 Time (s) 50 60 70 80 Figure 5.2. Trunk Length Variation during Lateral and Forward Reaching Task for a Subject with MS in the Wheelchair. Results from the elliptical path task in the angles shows less variation than the previous results since it was performed on a smaller space. Figure 5.3 shows a set of results for the same subject with MS for this task. In this task the individual did not return to the end of each set since this test was more continuous compare to the reaching task. The maximum trunk excursions were smaller than the ones corresponding to the reaching task. The maximum lateral excursion was 23.8 and maximum frontal was only 28.9. 80

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I f -:-----------{ 20 : I : c 10 !" : -_, --1 < 0 -+---------! : : : -_ -Flexion/Excursion Trunk Angle : : 1 -10 -Lateral Flexion/Extension Trunk Angle _t_ _________ L_ _______ _;_ _________ _! I o t I I 0 10 20 30 40 50 60 70 80 90 100 Time (s) Figure 5.3. Trunk Excursion Angles during the Elliptical Path Task for a Subject with MS in the Wheelchair. The length trunk had an initial value of0.447 m and the maximum value was 0 721 m. As well as the trunk excursion angles, the trunk length did not return to its original until the end of the triaL 0.75 .----------------------------.. 0.7 ,. .... 0.65 g 8 0.6 0.55 i5 r ---' ' 0.5 --------r-------r ------------r-----------r---------0.45 --------------r-----------r------------i-------------1-----0.4 +-------+--------r------i--------T-------l 0 20 40 60 80 100 Figure 5.4. Trunk Length Variation during the Elliptical Path Task for a Subject with MS in the Wheelchair 81

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5.1.2 Wrist Movement Results The trajectory followed by the right wrist location for a right-handed person with MS during a forward and lateral reaching task in the wheelchair is shown in Fig. 5. 5. Other initial locations are shown for reference: right greater trochanter (RGT), right acromium (RAC), the right elbow (RE), and the right wrist (RW). The trajectory was plotted with respect to the auxiliary coordinate system explained in section 4.1.3. The origin of the graph corresponds to the initial location of the mid greater trochanter (MGT). Figure 5 5 shows the effect of having the test performed on a tilt surface during the forward reach trajectory, where these ones were bent to the left, even though the subject was looking at a target located in front of the seating system. Figure 5 6 shows the wrist trajectory of the same subject with MS when the task is performed in a scooter For this case the same effect is seen but the trajectory is closer to a straight line Figures 5. 7 and 5. 8 show the trajectory of a person from the comparison group during the reaching task in a wheelchair and in a scooter respectively There is no bending of the trajectory because of the tilted surface. Another difference can be seen at the extreme position of each reach; the subject from the comparison group had a smoother trajectory than the subject with MS. 82

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1 0.8 I I I I -----;------------------------1-----------t------------r---------' -s 0.6 6 ' -----------0 ' ' ' ------------}------,tj ' 0 GJ ' ' = 0.4 Cl -------------------------------------------.. ------------____________ ... ____________ i 0.2 If 0 : : .... -----i ----+-----j--0 0 2 0.4 0 6 0.8 1 1.2 Dominant lateral Direction (m) Figure 5.5. Trajectory of the Wrist during the Forward and Lateral Reaching Task for a Subject with MS in the Wheelchair. 1 ,.-.... 0 8 o I I o o ------------r -r r -----r -r-------e 0.6 '-" I 0 I I 0 ------.-------------.-------------.----------,-------------.------------ I I I o .... 0 e 0.4 .... 0 I I I o t I I 0 I 0 I I o o I 0 0 I I I o I I I 0 I I I o I I I I I I I I I 0 __ ...... ___________ ..._ ___________ _, ____________ .. ____________ ___________ ' ' "0 ' a ' 0.2 I I I I ------------.--------. -----------:-------.-----.-------------:---------r ----------0 I I I ____________ ... __________ .......... _______ .. ___________ ... ____________ _. ____________ _, ___________ I I I I I I I I I I I I I 0 I I I I I I I I . I 1 I I I I 0 I o I I I I I I I I I -0.2 ' -0.2 0 0.2 0.4 0.6 0.8 1 1.2 Dominant Lateral Direction (m) Figure 5.6. Trajectory of the Wrist during the Forward and Lateral Reaching Task for a Subject with MS in the Scooter. 83

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1 ,_.._ 0.8 s '-' = 0 .... 0.6 0 ------------"------____________ .. ______ I I I I I +-::::::::::,::::::---::r::::::::::-::::::::::r:::::::::: (!) .!:I ' 0 ' ta 0.4 I I 0 I ----------... ------------.,-------------.-------------,------------1 I I I I I I I 0 0 I I I I I I I I I I I I I 0 ....:I "'1:1 0.2 t:a I I I 0 I o I I ------.J _______ -------------r------------;------------------------+--------0 .I I I I I I I __ _. ____________ _, _____________ ... ____________ .. ___________ I I I I -----------.. ----------I I I I I I I I I I I I I I I I I I 0 I ' ' -0.2 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 Dominant Lateral Direction (m) Figure 5.7. Trajectory of the Wrist during the Forward and Lateral Reaching Task for a Comparison Group Subject in the Wheelchair. 1 ,_.._ 0.8 e '-' I I I I -----------... ------------,-------------.------------... ------------' I I I I I I I I I I I ------------'1-------= I I I I I I I I I I I I 0 ' -a 0.6 (!) .... t5 I I I I I -... ----------... ------------.,-------------,------------'1----------l I I I I I I I I I I 0 I ' ' ' ------------,------e 0.4 (!) 1U ] 0.2 I I I I ---;------------;------------T----------;-----------. ' -------------------------' ------------,-------------------,--------n-.-= e; 0 0 r.. ' ------:-------------r-----;----------------------,-------------I ' ' ' ' -0.2 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 Dominant Lateral Direction (m) Figure 5.8. Trajectory of the Wrist during Forward and Lateral Reaching Task. for a Comparison Group Subject in the Scooter. 84

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The trajectory of the wrist during the path elliptical test for the same subject in the wheelchair is shown in Fig. 5.9. As well as the previous graph, these trajectories are plotted with respect to the auxiliary coordinate system. Crosses indicate the locations of the peg markers 0.8 e 0 6 ........ = 0 0 4 0 ..... 0 0.2 8 0 M0.2 M0.4 0 0.2 0.4 0.6 0.8 1 Dominant Lateral Direction (m) Figure 5.9. Right Wrist Trajectory during the Elliptical Path Task for a Subject with MS in the Wheelchair. Crosses indicate the Location of the Peg Markers. A single cycle from the elliptical path test shown before is presented in Fig. 5.10. In this case, the origin of the graph corresponds to the midpoint of the line that jointed the two marker pegs. The x-axis was defined by a vector going from the peg located in front of the subject to the peg located on the side. For this rightMhanded person the cycle was performed on the counter-clockwise direction, as indicated by the arrows. As specified in chapter 4, the beginning of the cycle was located as soon 85

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as the trajectory crosses the line that joints the two marker pegs (x-axis). For this case the path length was equal to 1,. 780 m. 0.4 ......... 0.2 a '-' = 0 0 = Q -0.2 Ci! = e -0.4 :: ::: :::::: : i:::::::: -:::::::_:,::: ::::::: -0.6 -0. 6 -0.4 -0. 2 0 0 2 0.4 0 6 Lateral DireCtion (m) Figure 5.10. Cycle during the Elliptical Path Task. A less smooth trajectory can be seen on Fig.5.11. This trajectory corresponds to the same subject when the elliptical path test was performed in the scooter. In some cycles the subject moved the functionally dominant hand out of the loop. Figures 5.12 and 5 .13 show the trajectories from a subject from the control group when the test was performed in the wheelchair and in the scooter respectively Contrarily to subjects with MS, the trajectories in both seating systems were similar. 86

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1 0.8 ,........ 0 6 El '-" = 0 ,::j 0 4 e 0 0.2 ]! = 0 ..... 0 -0. 2 -0.4 0 0.2 0.4 0.6 0.8 1 Lateral Direction (m) Figure 5.11. Right Wrist Trajectory during the Elliptical Path Task for a Subject with MS in the Scooter. Crosses indicate the Location of the Peg Markers. 0 7 0. 6 -1---------.0 0 1 0+-----+----i----1-----4 0 0.2 0.4 0.6 0.8 Lateral Direction (m) Figure 5.12. Right Wrist Trajectory during the Elliptical Path Task for a Comparison Group Subject in the Wheelchair. Crosses indicate the Location of the Peg Markers 87

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0.7 0.6 -----------1------------------,-... g 0.5 c: 0 .c 0.4 e a 0.3 'il = 0 0 2 0.1 0 0 0.2 0.4 0.6 0.8 Lateral Direction (m) Figure 5.13. Right Wrist Trajectory during the Elliptical Path Task for a Comparison Group Subject in the Scooter. Crosses indicate the Location of the Peg Markers. The vertical distance from the wrist to the acromium variations for the same previous subject with MS in the wheelchair from the forward and lateral reaching and elliptical path tasks are shown in Fig. 5.14 and Fig. 5.15 respectively. As well as the trunk excursion measurements, this quantity returned to its original position after each reach during the reaching task. During this task the initial value was 0.359 m, its minimum value occurred during extreme position of the lateral reaching (-0.06 m) and its maximum value occurred when the subject's hand touched the tight (0.414 m). The negative value indicated that the wrist was higher than the acromium. Smaller variation was found during the elliptical path task where the initial position was 0.440 88

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m. This quantity varied from 0.490 m to 0.723 m when completing the cycles of the task. 0.5 0 4 g 0 3 0 0 2 j 1'1> 0.1 0 0 -0.1 -0.2 . ---------------r -----"' ______ .f.l -r---i"''------fi -----+------,..---------. ---------_____ .. ------------.......... -----------... --------------0 . . . ---------.. ----------------------------.... ----------------. : : t r -----l-J ---------V---------v--f -------\J--------....... -\J -----------v ---t----v ---------r-v --------------_____________________ .. _____________________ .. _____________________ .. ___ .. ________________ 20 40 Time (s) 60 80 Figure 5.14. Vertical Distance from the Wrist to the Acromium during the Lateral and Forward Reaching Task for a Subject with MS in the Wheelchair. 0.35 0.3 -----------t-----------;-------------l------------;-------------t-----------;-----------' I I I I I ----------------------------------------.. ---------------------------... -------------------------0.25 s ';;' 0.2 1'1> 0.15 . i5 0 I I I I .1 ------_1 ____ -----r--------------:--------------r--------------r-------------1--------------. . 0 I I I > _____________ .._ ____________ .. ____ .,. _________ ._ _____________ ______________ ._ __ ,. __________ _____________ I I I I I I 0.05 o I I I I I 0 I I I I I I I I I I 0 o o o 0 I o 0+-----+: ____ -r: ____ ____ 0 20 40 60 80 100 120 140 Time (s) Figure 5.15. Vertical Distance from the Wrist to the Acromium during the Elliptical Path Task for a Subject with MS in the Wheelchair 89

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In order to evaluate the reaching ratios presented in section 4.4.2.3.2 the arm length was averaging the arm length values. A variation of this distance is shown in Fig. 5.16, where the average value was 0.597 m, the maximum value was 0.635 m and the minimum value 0.561 m, therefore the total variation was 6.4% of the average value. -0.64 0.63 0.62 ,, 0.61 -5 01) 0.60 ..:I 0.59 0.58 0.57 0.56 .. --------- .. -.. -----.. -r ---r---.... --- ' ' -----------------r---... ----------r-------------------r--------------------. "' '- .L ' ' ' ------------r ---------r--------r -----------------------------------------------: ----------------------------------------_ .. ---------------' ------------------------------------------------------' ::: _: _::::: :::::: : r::::::::: __ ::::: t:::::: : _:: __ ::::::::: L: __ :: ::::::::::::: 0.55 +-------r-----r-----r-------i 0 20 40 60 80 Time (s) Figure 5.16. Arm Length Variation during the Lateral and Forward Reaching Task for a Subject with MS in the Wheelchair 5.1.3 Posture Results The trunk-leg and knee angle results from the same subject with MS in the wheelchair during the reaching task are shown in Fig. 5.17. For this subject with MS the trunk-leg angle average in the wheelchair was 115", its maximum value was 71", and its minimum was 85 .2 The knee angle had minimum variation, less than 5% variation in both cases and its average value was 95 90

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120 100 80 ........ v ..2 60 btl 40 20 0 0 ' 0 0 --------------- .J. -------'"-----------.. ------.. ___ ------1 I I I I I I 0 I I ' ' I I I 0 I I ____________ .. _____________ .. ____________ ... _____________ ,.. ____________ .. I I I I I I I I I I o I I I I 0 I 0 I I o I o o I I 0 I I o I I I I I I I I I I I I I I I 0 I I t I I r -Trunk-Leg Angle ---r----------r------r--------r---------- I I I 0 -------+ -Knee Angk -r---------r---------r -----_;_____ ---10 20 30 40 Time (s) so 60 70 80 Figure 5.17. Posture Angle Results during the Lateral and Forward Reaching Task for a Subject with MS in the Wheelchair. Figure 5.18 shows the measurements during the elliptical path task. The trunkleg angle had a maximum value of 108 and a minimum of74. Its average value was 92.7. The knee angle had an average value of 96.1 with minimum variation. 0 20 40 60 80 100 120 140 Time (s) Figure 5.18. Posture Angle Results during the Elliptical Path Reaching Task for a Subject with MS in the Wheelchair. 91

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Finally for the postures angles, the leg deviation angle results are presented Some differences can be seen between the results in the wheelchair and in the scooter. Figure 5.19 shows the results in the wheelchair, where both angles have a repetitive behavior with an average value of 18.1 and -3.4 o. The directions of the angles were set according to Fig. 4.17. For this case both legs are pointing to the dominant side. Figure 5 20 shows the results in the scooter, where both legs increased its value along the time towards the dominant side. The average values were 15 and -4.9 for the dominant and non-dominant side respectively, which indicates that both leg were deviating towards the dominant side. 30 25 20 .._, Q) 15 = 10 0 5 ..... 0 0 ...:I -5 -10 -15 0 10 20 30 -Dominant Leg -Non-Dominant Leg 40 Time (s) 50 60 70 80 Figure 5.19. Leg Deviation Angles during the Lateral and Forward Reaching Task for a Subject with MS in the Wheelchair. 92

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30 25 ::....-20 ()) OJ) 15 s:: 10 0 5 :;: ()) -----..1-----------___ .__ ----------' ' Cl 0 OJ) ______ ., _____________ .. ____________________ _,_ ------------------------------------------------' ()) -5 -10 -15 I I I I ______________ ........... .J ..................................... .... :--------------------i -Dominant Leg j ----------------r----------------Non-Dominant Angle :-------------------0 10 20 30 40 50 Time (s) Figure 5.20. Leg Deviation Angles during the Lateral and Forward Reaching Task for a Subject with MS in the Scooter. The deviation angles for the same person during the elliptical path task are shown in Figures 5.21 and 5.22. Figure 5.21 shows the results in the wheelchair, where the dominant side leg increased its value, having an average value of28. The non-dominant side leg had a stable behavior with an average of 4.1". Figure 5.22 shows the results in the scooter where the deviation is more severe on the nondominant side leg. The average values are 19.3" and 3.4" for the dominant and nondominant side legs respectively. 93

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Q) eo = 0 ..... > Q) Q eo Q) .....:! 35 ------t-------.-.... ------or---- .. -....... _,..,,,,,,,,,,,,,._,,,,_,_, __ ,_,,,,.,,,,_,,,, .. _,_ ... : . : I o o I o : I I I I I t 30 _______________ ; _______________ L... : : _______ _..! I I ; l I I I 0 I 0 i 25 o o I ---------------___ ____ .. -----------------------------------.. ..;. ---------------i : : : : : : i : : : : I I I I : 20 15 ------------__ J. -----------. ----.---.L --------: : ------------_ J j j : -Dominant Leg ---------------]-----------+--------+----Leg: -------------I I o I I o : I I o I I o : 10 _______________ ; _______________ j_ _______________ _______________ : _______________ ; _______________ j_ _______________ j : : : : : : i : : : : : : i : : : : : : i 5 ....... ""------_.,: ____ ,. ___ -----!.----------------------------------.!----------------i I o I I J 0 i 0 20. 40 60 80 100 120 140 Time (s) Figure 5.21. Leg Deviation Angle during the Elliptical Path Reaching Task for a Subject with MS in the Wheelchair. 25 ;._.. 20 0 Qo c < 15 c 0 -.:::: CIS :; 10 0 Q 01) .s 5 0 ----r------r---:------r--r----r--:---T-T---1 .. ----'.. -------'-----' ' l l l I ----------r----------1----------1----------1---0 : : : : i I I 0 0 : I I I 0 : 10 20 30 40 50 Time (s) 60 70 i i 80 90 100 Figure 5.22. Leg Deviation Angle during the Elliptical Path Reaching Task for a Subject with MS in the Scooter. 94

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5.1.4 Center of Pressure Results The FSA system provided the information from the body-seat interface as shown in Fig.5.23 for every instant at a rate of 10Hz. The data from the center of pressure location was extracted to perform the analysis of the COP movement. 0 2 1 250 1 0 A B u 225 0 0 c ;;, O O D ffi! 200 0 0 0 0 1 0 0 0 0 0 p !ii!! 0 mmHg sensors Included Variation coefllcient Standard deviation Average pressure Maximum pressure Center of pressure 183 108 7% 33.7 31 178 9.2, 9 5 Figure 5.23. Data provided by the FSA System for a Given Frame. Pressure distribution and its corresponding center of pressure location are displayed. The variation of the COP displacement for a left-handed subject with MS is shown in Fig. 5 24 Peak values corresponding to the frontal reaching are higher than those corresponding to the lateral reaching. However, the frontal displacement peaks are always followed by a dramatic decrease COP displacements from the same person during the elliptical path test are shown in Fig.5.25. 95

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0.14 -E! 0.12 '-' 5 0.1 0.08 (IS 0 G) 0 04 .... ii 0.02 J: 0 tcg a-o.o2 .... 8-0.04 -----------------r-----------------r--Frontal Displacement ' ................. ............ .. ... -Lateral Disp1acement ........... ----. ' --------,.--------------.------------------' ' -----,---------------.---------------,-----------------' ' ' ' -.------------------.-----------------0.06 -t-----ii-----i-----+----+------ii-----1 0 5 10 15 Time (s) 20 25 30 Figure 5.24. COP Displacement during Lateral and Forward Reaching Task for a Subject with MS in the Wheelchair. 0.14 ------:---------:---.. I I : 0.12 _, 0.1 .... 5 0.08 e Q) 0 0.06 = p.. rn 0.04 -Cl 12 0.02 ::s rn 0 rn 12 -0.02 '"'"' 0 .... -0.04 = -0.06 Q) u ..................... !.. --Frontal Displacement .... ...................... : i -Lateral Displacement : 1 I I I I : ----------------.. .,.. .. ..................... ----.-----------,... -.. -., ......... ------------: I I I I : 0 0 0 I : t 0 0 : o 0 I I : I I I I ; --.... ... .. ... ---.. ----. -.... ---... .. -------------: : : : : ; : : : : .... .. .... .. .. :-.. .. .. 0.. ... .... -: -.. ____________ : .. ... : : .. .. : : .. .. .. .. .. .. I I ------------------------------' : ............ 1 I 0 10 20 30 40 50 Time (s) Figure 5.25. COP Displacement during the Elliptical Path Task for a Subject with MS in the Wheelchair. 96

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5.2 Data Summary Average values and companson p-values from the lateral and forward reaching task are presented first, then results from the elliptical task are shown, and finally, results from the can stacking task. In addition to the average values, standard deviations are also shown. If the data set had skewness value less or equal to 1, it was considered to have a normal distribution, therefore the p-value considered was the corresponding to the parametric test (student t-test). If the skewness of the data set was greater than 1, the p-value considered was the corresponding to the non-parametric test (Wilcoxon). Complete data of the tasks including skewness, results from both parametric and non-parametric p-values, and individual results for each group can be found in AppendixJ. 5.2.1 Seating System Comparison Results 5.2.1.1 Lateral and Forward Reaching Task Results Results from the comparison group showed no significant differences when the test was performed in the two seating systems. Results from the subjects with MS showed significant differences in some measures, as explained below Table 5.1 shows the average values for subjects with MS. The comparison p-values are shown in Table 5.2. Average values from the comparison group are shown in Table 5.3 and their corresponding comparison p-values are shown in Table 5.4. Comparison tests 97

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between groups showed that the comparison group had greater values than subjects with MS in most of the measures, the comparison p-values are shown in Table 5 .5. For subjects with MS, 9 out of 15 measures showed significant differences A 2.5 decrease was present on the average trunk flexion/extension angle when the task was performed in the scooter. No significant differences were found on the frontal COP movement between the scooter and the wheelchair. Lateral COP excursion in the scooter, measured as the Root Mean Square (RMS) of the COP movement, during the initial reaching task was greater than in the wheelchair. Lateral COP measurements in the scooter during the initial reaching task were greater than in the wheelchair. However, during the final reaching task they decreased at the same amount as the wheelchair values, which did not vary from the initial values For that same group, the knee angle when the test was performed in the scooter remained close to 90 and it was 15 greater than the knee angle in the scooter. Significant differences were found on the angle deviation of the non dominant side leg; when the test is performed in the wheelchair, both legs were abducted, in other words, the dominant side leg was toward the dominant side and the non-dominant side leg was toward to the non-dominant side However in the scooter, the legs were wind-swept to the dominant side, this is, both legs were toward the dominant side. 98

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Table 5.1. Lateral and Fotward Reaching Task Results for Subjects with MS. Seating System (Standard Deviations Measurement are Shown in Parentheses) Wheelchair Scooter Initial Final Initial Final Average Trunk Flexion/ Extension 0.22 1.70 5.04 2.56 Angle CO) (13.68) (14.03) (10.93) (12.36) Average Lateral Trunk 9.36 8.38 10.07 11.28 Flexion/Extension Angle CO) (4.56) (4.69) (4.55) (4.13) Maximum Trunk Flexion/ 21.61 24.78 23.57 22.79 Extension Angle CO) (17.93) (13.36) (14.86) (14.61) Maximum Lateral Trunk 26.71 26.71 25.31 24.24 Flexion/Extension Angle CO) (10.63) (9 03) (10.53) (9.03) Total Path Length (m) 16.38 15.97 14.96 15.44 (2.37) (2.36) (1.89) (2.10) Lateral Reach Ratio 0.99 0.90 0.92 0 .91 (0.21) (0.25) (0.25) (0.16) Frontal Reach Ratio 1.20 1.16 1.15 1.15 (0.33) (0.28) (0.31) (0.28) Average of COP Frontal 0.039 0 041 0.037 0.035 Displacements (m) (0.029) (0 030) (0.034) (0.032) Frontal COP RMS (m) 0.013 0 011 0.015 0.014 (0.008) (0 007) (0.011) (0.010) Average ofMaximum COP Lateral 0.047 0 047 0.052 0.045 Displacements (m) (0.029) (0.026) (0.041) (0.038) Lateral COP RMS (m) 0.017 0.020 0.022 0.019 (0.010) (0 011) (0.013) (0.012) Distance from Mid Acromium to 0.575 0.569 0.576 0.573 MidGT(m) (0.031) (0.036) (0.038) (0.045) Height from Wrist to Shoulder (m) 0.157 0.154 0.140 0.163 (0.077) (0.078) (0.106) (0.072) Trunk Leg Angle CO) 82.5 83.7 87.4 85.1 (8.4) (7.6) (8.1) (9.3) Knee Angle (0 ) 73.8 74.8 91.8 90.5 (15.3) (15.2) (13.2) (10.4) Angle Dominant Side Leg 4.7 6 1 2.4 5.8 (8.4) (10.7) (9.7) (11.8) Deviation Non-Dominant Side 5.6 4.4 -0.1 -3.0 CO) Leg (4.0) (5 0) (11.7) (13 7) 99

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Table 5.2. Lateral and Forward Reaching Task Results: Seating System Comparison Performed on Subjects with MS. Comparison of Means p-value (NonParametric Values are Shown in Italic and Measurement Significant Differences in Bold Case) Initial to Final Wheelchair to Reaching Task Scooter Wheelchair Scooter Initial Final Average Trunk Flexion/ Extension 0.31 0.16 0.08 0.44 Angle from Vertical 0.45 0.17 0.07 0.53 Average Lateral Trunk 0.24 0.39 0.47 0.02 Flexion/Extension Angle 0.17 0.65 0.65 0.01 Maximum Trunk Flexion/ Extension 0.89 0.31 0.34 0.87 Angle 0.80 0.58 0.44 0.96 Maximum Lateral Trunk 0.50 0.97 0.21 0.74 Flexion/Extension Angle 0.33 0.72 0.37 0.65 Total Path Length 0.38 0.11 0.02 0.23 0.45 0.14 0.02 0.24 Lateral Reach Ratio 0.08 0.91 0.16 0.84 0.04 0.26 0.21 0.74 Frontal Reach Ratio 0.27 0.88 0.30 0.82 0.16 0.48 0.31 1.00 Average ofMaximum COP Frontal 0.69 0.75 0.76 0.33 Displacements 0.58 0.92 0.80 0.20 Frontal COP RMS 0.35 0.62 0.51 0.40 0.40 0.96 0.44 0.37 Average ofMaximum COP Lateral 0.92 0.22 0.63 0.82 Displacements 0.52 0.26 0.80 0.44 Lateral COP RMS 0.24 0;10 0.14 0.93 0.48 0.06 0.26 1.00 Distance from Mid Acromium to Mid 0.24 0.635 0.90 0.61 GT 0.06 0.575 0.859 0.575 Height from Wrist to Shoulder 0.53 0.12 0.21 0.08 0.40 0.07 0.34 0.08 Trunk Leg Angle 0.45 <0.01 0.04 0.43 0.76 <0.01 0.05 0.45 Knee Angle 0.62 0.34 <0.01 <0.01 0.92 0.33 <0.01 <0.01 Dominant Side 0.19 0.26 0.35 0.93 Angle Deviation Leg 0.20 0.09 0.29 0 .96 Non-Dominant 0.09 0.09 0.19 0.13 Side Leg 0.10 0.04 0.26 0.20 100

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Table 5.3. Lateral and Forward Reaching Task Results for the Comparison Group. Seating System (Standard Deviations are Shown in Parentheses) Measurement Reaching Task Reaching Task on Wheelchair on Scooter Initial Final Initial Final Average Trunk Flexion/ Extension 4 33 6.02 6.24 6.74 Angle from Vertical CO) (7.34) (7.54) (7.31) (7.94) Average Lateral Trunk 12.59 13.19 12.19 12.10 Flexion/Extension Angle CO) (6.99) (6 25) (6.27) (6.57) Maximum Trunk Flexion/ 44.0 43.8 44.1 41.1 Extension Angle CO) (11.1) (12.5) (11.8) (11.3) Maximum Lateral Trunk 38.8 40.7 40.5 37.2 Flexion/Extension Angle CO) (7.3) (7.5) (7.9) (6.9) Total Path Length (m) 17.59 17.41 16.99 16.80 (1.65) (1.69) (1.31) (1.54) Lateral Reach Ratio 1.25 1.25 1.41 1.28 (0.10) (0.09) (0.29) (0.13) Frontal Reach Ratio 1.71 1.71 1.69 1.70 (0.18) (0.20) (0.11) (0.11) Average ofMaximum COP Frontal 0.032 0.031 0.030 0.031 Displacements (m) (0.011) (0 013) (0 005) (0.008) Frontal COP RMS (m) 0.011 0.009 0.014 0.006 (0.011) (0 011) (0.024) (0.014) Average ofMaximum COP Lateral 0.047 0.046 0.041 0.043 Displacements (m) (0.011) (0.013) (0.006) (0.008) Lateral COP RMS (m) 0.031 0 025 0.008 0.020 (0.038) (0.034) (0.048) (0.024) Distance from Mid Acromium to 0.652 0.654 0.637 0.685 MidGT(m) (0.063) (0.059) (0.047) (0.065) Height from Wrist to Shoulder (m) 0.218 0.234 0.220 0.232 (0.032) (0.032) (0.030) (0.039) Trunk Leg Angle CO) 84.5 85.6 84.1 88.0 (7.1) (9 6) (9.4) (5.4) Knee Angle (0 ) 85.8 85.1 83.9 86.9 (13.0) (15.1) (7.0) (6.4) Dominant Side 4 5 3.4 4.6 4.9 Angle Deviation Leg (0.5) (2.6) (0.6) (0.4) CO) Non-Dominant 2.9 3.0 2.8 2.9 Side Leg (0.6) (0.3) (0.4) (0.3) 101

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Table 5.4. Lateral and Forward Reaching Task Results: Seating System Comparison Performed on the Comparison Group. Comparison of Means p-value (NonParametric Values are Shown in Italic and Measurement Significant Differences in Bold Case) Initial to Final Wheelchair to Reaching Task Scooter Wheel-chair Scooter Initial Final Average Trunk Flexion/ Extension 0.23 0.58 0.38 0.67 Angle from Vertical 0.29 0 58 0.51 0.72 Average Lateral Trunk 0.66 0.93 0.86 0.25 Flexion/Extension Angle 0.72 0.51 0.58 0.24 Maximum Trunk Flexion/ Extension 0.91 0.07 0.97 0.09 Angle 0.96 0.14 0.68 0.11 Maximum Lateral Trunk 0.24 0.02 0.56 0.04 Flexion/Extension Angle 0.21 0.03 0.65 0.09 Total Path Length 0.59 0.42 0.07 0.14 0.29 0.29 0.06 0.09 Lateral Reach Ratio 0.79 0.22 0.15 0.49 0.97 0.33 0.04 0.11 Frontal Reach Ratio 0.93 0.66 0.80 0.90 0.88 0.29 0.80 0 68 Average ofMaximum COP Frontal 0.24 0.42 0.48 0.97 Displacements 0.23 0.45 0.72 0.38 Frontal COP RMS 0.45 0.23 0.57 0.60 0.33 0.11 0.80 0.44 Average of Maximum COP Lateral 0.90 0.81 0.86 0.89 Displacements 0. 86 0.48 0.90 0.81 Lateral COP RMS 0.61 0.37 0.21 0.50 0.68 0.44 0.33 0.31 Distance from Mid Acromium to Mid 0.935 0.189 0.656 0.162 GT 0.89 0.24 0.70 0.23 Height from Wrist to Shoulder 0.138 0.203 0.766 0.884 0.14 0.23 0.74 0.90 Trunk-Leg Angle 0.601 0.170 0.868 0.279 0.56 0.19 0.89 0.31 Knee Angle 0.766 0.187 0.491 0.581 0.80 0.18 0.54 0.47 Dominant Side 0.259 0.255 0.870 0.156 Angle Deviation Leg 0.26 0.29 0.90 0.20 Non-Dominant 0.276 0.219 0.708 0.517 Side Leg 0.31 0.26 0.80 0.629 102

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Table 5.5. Comparison of Means p-value between Groups for the Lateral and Forward Reaching Task. Comparison of Means p-value (Significant Differences are Shown in Bold Case) Measure Test Wheelchair Scooter First Reach Second First Reach Second Reach Reach Average Trunk Flexion/ p 0.17 0.19 0.41 0.19 Extension Angle from Vertical N-P 0.12 0.12 0.16 0.07 Lateral Average Trunk p 0.31 0.11 0 .31 0.87 Flexion/ Extension Angle N-P 0.07 0.04 0.21 0.21 Maximum Tnmk Flexion/ p 0.01 0.01 0.01 <0.01 Extension Angle N-P 0.02 0.03 0.01 0.01 Maximum Lateral Trunk p 0.01 0.01 0.02 0.02 Flexion/Extension Angle N-P 0.02 0.01 0.02 p 0.09 0.11 0.04 0.14 Path Length per Cycle N-P 0.16 0.26 0.12 0.26 p 0.01 <0.01 <0.01 <0.01 Lateral Reach Ratio N-P 0.05 0.02 0.01 0.01 p <0.01 <0.01 <0.01 <0.01 Frontal Reach Ratio N-P 0.02 0.02 0.01 0.01 Frontal Average p 0.93 0.65 0.49 0.78 Displacement N-P 0.83 0.53 0.27 0 .83 p <0.01 <0.01 0.01 <0.01 Frontal COP RMS N-P 0.03 0.01 0.04 0.03 Lateral Dominant Side p 0.17 0.13 0.86 0.05 Average Displacement N-P 0.26 0.29 0.78 0.11 Lateral Dominant Side p <0.01 <0.01 0.01 <0.01 COPRMS N-P 0.01 0.01 0.03 0.03 Distance from Mid p 0.15 0.17 0.16 0.18 Acromium to Mid GT N-P 0.25 0.21 0.24 0.24 Note: (P = Parametric N-P =Non-Parametric) 103

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Table 5.5 (Cont.). Comparison of Means between Groups p-value for Lateral and Foxward Reaching Task. Comparison of Means p-value (Significant Differences are Shown in Bold Case) Measure Test Wheelchair Scooter First Reach Second First Second Reach Reach Reach Height from Wrist to p 0.17 0.13 0.18 0.23 Shoulder N-P 0.26 0.29 0.16 0.19 p 0.17 0.17 0.18 0.19 Trunk-Leg Angle N-P 0.23 0.26 0.23 0.21 p 0.15 0.19 0.12 0.22 Knee Angle N-P 0.23 0.22 0.16 0.29 Dominant p 0.35 0.37 0.46 0.28 Angle Side Leg N-P 0.28 0.41 0.44 0.24 Deviation Non-p 0.27 0.14 0.15 0.27 Dominant Side Leg N-P 0.24 0.21 0.16 0.18 Note: (P = Parametric N-P =Non-Parametric) 5.2.1.2 Elliptical Path Task Results The comparison group had greater values compared to the MS population in most of the measures performed. No significant differences have been found on the comparison group. In the group of subjects with MS, 4 out of 13 measures showed significant differences During the elliptical path test, the COP movement in the lateral direction had a greater RMS value in the wheelchair. The knee angle when the task was performed in the scooter was 88, 16 greater than in the wheelchair. The angle deviation of both legs had significant differences. In the wheelchair, the deviation angles show that the legs were wind-swept to the dominant side and in the scooter the legs were abducted. Average values and comparison p-values for the 104

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seating system comparison performed on patients with MS are shown in Table 5.6. The results for the comparison group are shown in Table 5. 7. The results of the comparison between the two groups are shown in Table 5.8. Table 5.6. Elliptical Path Task Results: Seating System Comparison Performed on Subjects with MS. Seating System (Standard Comparison of Measurement Deviations are Shown in Means p-value (NonParentheses) Parametric Values are Wheelchair Scooter Shown in Italic) Average Trunk Flexion/ 14.27 11.25 0.22 Extension Angle from Vertical CO) (6.94) (9.69) 0.33 Average Lateral Trunk 16.47 14.92 0.62 Flexion/Extension Angle CO) (9.12) (6.34) 0.87 Path Length per Cycle (m) 1.74 1.71 0.68 (0.62). (0.47) 0.72 Frontal Average Displacement 0.011 0.007 0.36 (m) (0.008) (0.010) 0.26 Frontal COP RMS (m) 0.018 0.013 0.20 (0.011) (0.012) 0.17 Lateral Dominant Side Average 0.015 0.001 0.11 Displacement (m) (0.036) (0.026) 0.12 Lateral COP RMS (m) 0.037 0.018 0.02 (0.017) (0.009) 0.02 Distance from Mid Acromium to 0.601 0.602 0.99 MidGT(m) (0.035) (0.043) 0.65 Height from Wrist to Shoulder 0.234 0.320 0.11 (m) (0.141) (0.112) 0.13 Trunk Leg Angle (0 ) 91.0 91.1 0.96 (8.8) (8.7) 0.88 Knee Angle CO) 74.7 88.9 <0.01 (14.2) (12.7) 0.01 Dominant Leg 2.2 9.2 0.04 Angle (13.0) (10.3) 0.04 Deviation CO) Non-Dominant -5.8 6.5 0.06 Leg (6.4) (18.7) 0.11 105

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Table 5.7. Elliptical Path Task Results: Seating System Comparison Performed on the Comparison Group. Seating System (Standard Comparison of Means Measurement Deviations are Shown ii1 p-value (NonParentheses) Parametric Values are Wheelchair Scooter Shown in Italic) Average Trunk Flexion/ 13.64 14.00 0.78 Extension Angle from Vertical (0 ) (3.35) (5.24) 0.80 Average Lateral Trunk 14.24 12.97 0.53 Flexion/Extension Angle (D) (3.75) (5 02) 0.58 Path Length per Cycle (m) 1.88 1.85 <0.01 (0.03) (0.03) <0.01 Frontal Average Displacement 0.013 0.012 0.93 (m) (0.014) (0.014) 0.72 Frontal COP RMS (m) 0.025 0.020 0.26 (0.016) (0.012) 0.24 Lateral Dominant Side Average 0.046 0 034 0.06 Displacement (rn) (0.021) (0.015) 0.07 Lateral COP RMS (m) 0.055 0.032 0.04 (0.023) (0 031) 0.05 Distance from Mid Acromium to 0.681 0 680 0.961 MidGT(m) (0.059) (0.081) 0.857 Height from Wrist to Shoulder 0.283 0.281 0.852 (m) (0.137) (0 135) 0.659 Trunk Leg Angle (D) 102.8 102.7 0.967 (9.8) (12.6) 0.989 Knee Angle (D) 84.3 88.6 0.237 (15.6) (13.7) 0.325 Dominant Leg 2.5 3.0 0.010 Angle (0.4) (0.3) 0.015 Deviation (D) Non-Dominant 2.4 2.9 0.013 Leg (0.4) (0.4) 0.016 106

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Table 5.8. Comparison of Means p-value for the Elliptical Path Test. Comparison of Means p-value (Significant Differences are Shown Measure Test in Bold Case) Wheelchair Scooter Average Trunk Flexion/ Extension p 0.76 0.16 Angle from Vertical N-P 0.33 0.05 Lateral Average Trunk Flexion/ p 0.75 0.67 Extension Angle N-P 0.78 0.67 p <0.01 <0.01 Path Length per Cycle (m) N-P <0.01 <0.01 p 0.75 0.44 Frontal Average Displacement N-P 0.40 0.12 p 0 26 0.15 FrontalRMS N-P 0.21 0.07 Lateral Dominant Side Average p 0.06 0.01 Displacement N-P 0.05 0.02 p 0.08 0.20 Lateral Dominant Side RMS N-P 0.04 0.16 Distance from Mid Acromiurn to Mid p 0.85 0.64 GT(m) N-P 0.70 0 62 p 0.94 0.74 Height from Wrist to Shoulder (m) N-P 0.90 0.82 p 0.85 0.64 Trunk-Leg Angle CO) N-P 0.81 0.84 p 0.55 0.74 Knee Angle CO) N-P 0.56 0.75 Angle Deviation Dominant Leg p 0.78 0.82 CO) Non-Dominant N-P 0.67 0.78 Leg Note: (P = Parametric N-P =Non-Parametric) 107

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5.2.1.3 Can Stacking Task Results Results show that the comparison group subjects had faster completion times in all cases. No significant differences have been found between seating systems. Values are shown in Table 5.9. Table 5.9. Can Stacking Tasks Results. Completion Time (s) Comparison of Means Group (Standard Deviations are shown p-value (Non-in parentheses) Parametric Values are Wheelchair Scooter Shown in Italic) Subjects with MS 7.51 8.12 0.321 (4.31) (5.42) 0.575 Comparison Group 3.60 3.64 0.776 (0.39) (0.44) 0.721 Comparison of Means p<0.01 <0.01 value (Non-Parametric <0.01 <0.01 Values are Shown in Italic) 5.2.2 Order Performed Comparison Results No significant differences were found on the order performed comparison in the group of subjects with MS, there was no learning effect in this group. The comparison group showed significant difference only during the can stacking task. The completion time was significantly smaller when this task was completed on the second seating system tested, showing that there was a learning effect on this group. Results from this comparison can be found in Appendix K. 108

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5.2.3 Correlation Test Results From these tests, only the pair Trunk-Leg Angle and Frontal COP RMS showed a correlation factor greater than 0 6 during the reaching and elliptical path tasks. 5.2.4 Group Ranking The following results were an attempt to differentiate the performance of the comparison group from the subjects with MS. Figure 5.26 shows the data from the can stacking task. The comparison group is identified as subjects 1 to 10 and the subjects with MS are identified as subjects from 11 to 20. The two subjects with MS with the fastest completion time were faster than the slowest subject from the comparison group. 25 ____________________ 20 1 i r!J . -------------------o..-------------------"--------------------o Wheelchair ' ll Scooter 10 i i 1 8 l 5 ____________________ j _____________________ ___________________ ; __________________ i I 0 5 10 15 20 25 Subjects Figure 5.26. Can Stacking Completion Time Results. 109

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Figure 5.27 shows the same analysis for the path length per cycle during the elliptical path task. It can be noticed that for the comparison group this quantity varies from 1.52 m to 2.41 and for the subjects with MS it varies from 0.92 to 2.73, which indicates that subjects with MS had the results spread compared to the comparison group. 3.0 .... ------.........-;-------,------:------; o Wheelchair j j 0 I 6. Scooter .. L ................... \ ................... : 2 i 6. i l : i 0 i i ..... ...... ---; ......... ----------;.. ........ : ------------. 6.1Z1: : : 6.6. : 0 0 : : : 0 : i i .t.OD i i 0 D 0 i ------.... ---t --------------.... --.-1--.------... --.... ; ... --....... ----. ---1 1-< Cl) Q., 1.5 oj OJ) c:: Cl) 1.0 5 2.5 --CI) 0 6 2.0 0 I I I ; o o I I : I I I I : o I o I I I : 0 I I : -----:----MS -------1 0.5 0 5 10 15 20 25 Subjects Figure 5.27. Path Length per Cycle Results. Another analysis performed was the study of the behavior of the path length per cycle along the number of cycles for the comparison group and subjects with MS. No significant differences were found between the seating systems Figure 5.28 shows the values and the comparison of means p-values. As it can be seen, the p110

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value was always greater than 0.4, then no significant differences were found between the two groups on each seating systems. 2.4 -r--;::==============;----r Comparison Group in Wheelchair -Q.- Comparison Group in Scooter 2.2 ....... Subjects with MS in Wheelchair 8. Subjects with MS in Scooter Comparison p-value in Wheelchair 2.0 p-value in Scooter ' ---------------r --------------...--------------r----' ... ..... 0.5 . ' . ' -t----+---i-----+------1'----;---+ 0.0 0 5 10 15 Cycle 20 25 Figure 5.28. Path Length per Cycle Variation. 30 In other to eliminate the effect the arm length on the path length the quotient of the path length per cycle and the arm length was analyzed Figure 5.29 shows the results from this analysis were comparison p-values between the two groups 111

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presented a decreasing trend along the number of cycles. Comparison p-values smaller than 0.22 can be found at the last cycle This indicates that the path length per cycle per arm length for the comparison group could be significantly greater than the same measure for the subjects with MS if the number of cycles is increased. 6.0 Comparison Group in Wheelchair 5.0 _g_-Comparison Group in Scooter Subjects with MS in Wheelchair fs Subjects with MS in Scooter Comparison p-value in Wheelchair D Comparison p-value in Scooter ... ':" c.. til a :E 0 06 til c C!$ c.. o.4 e 8 0 2 -+----r----r----+----+----+---t-0 0 0 5 10 15 Cycles 20 25 30 Figure 5.29. Path Length per Cycle per Arm Length Results. 112

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6. Discussion, Conclusions And Recommendations 6.1 Discussion The main purpose of the study was to investigate if the seating systems used by people with MS will affect their upper extremity function and posture. Of the performance measures evaluated in the group of subjects with MS (See Tables 5.2 and 5 6), the lateral center of pressure (COP) excursion was significantly greater in the customized seating system. Significant differences were found on the deviation angle of the non-dominant side leg too. On the functionally non-dominant side, the angle of deviation of the leg during the elliptical path task in the customized seating system was negative having the legs a wind-swept position. In the non-customized seating system that angle was positive, having the legs an abducted position. However, during the lateral and forward reaching, the contrary occurs the abduction position corresponds to the customized seating system and the wind swept position to the non-customized one The knee angle was significantly greater and closer to 90" in the non-customized seating system. There were no differences between seating systems in the total path length of upper extremity excursion and trunk (forward and lateral) excursion in any of the tasks. No differences were found in the completion time during the can-stacking task 113

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No significant correlations were found in most of the pairs analyzed (Section 3.5.3). A slight correlation, between the frontal excursion of the COP and the trunk leg angle were found. The order of the seating systems being tested was not significant. It appears that any learning effect was non-contributory to improving performance. It also appears that fatigue, in these subjects with MS, did not significantly contribute positively or negatively to performance in our measures. The comparison group showed no differences between performing in the customized and non-customized seating systems. As expected, the comparison group performance was independent of seating systems Subjects in this group were able to compensate for the external variables in order to maintain performance in both seating systems. Their performance in most of the cases was always greater than the performance of people with MS, regardless of seating system. This pilot study faced many challenges, and some methodological issues need to be addressed. The overall premise of the study was based on clinical observations by seating professionals. These observations suggest that there is compromised upper extremity function and chronic postural deterioration when persons with MS are seated in a non-customized seating system. Because the study looked at performance over a 4-hour period, chronic changes may not be identifiable. Another limitation may be that the measures chosen to test our hypotheses were not sensitive enough to demonstrate differences. This study was an attempt to 114

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find new quantitative methods of measuring performance. Quantities such as path length have not been previously utilized to measure functional performance. In addition to that, since the test was performed on a lateral tilted ramp, performance could have been dramatically decreased since subjects with MS may have hesitated to perform the test in a better way. This study included a small sample size of ten people with MS and ten people in the comparison group Due to the high variability in the impairments among people with MS, it is very difficult to assess all aspects of the disease. MS has a wide range of symptoms, and each of one an its severity affect the persons in a very different way. One way to address this issue would be having subjects with the same level of the disease In this study, subjects that were included into the study had a Kurtzke Scale rating between five and eight. For this study, 80% percent of the population who participated used a wheelchair as a primary mobility aid. Having a non-familiar seating system could have made subjects with MS to hesitate their performance Even though they had a 10-minute period to become familiar with these seating systems, this period of time may not be enough. Results of this study cannot be extrapolated to a usual population of MS. Ninety percent of the population in this study was male, which makes it unique. Approximately only 33% of a MS usual population is male. 115

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6.2 Conclusions The results of the present study show that there is no overall difference between the performances of subjects with MS in the two seating systems tested There was no difference on the performance of the control group, but the performance of this group was greater than the performance of the subjects with MS For subjects with MS, since no significant differences were present on measures related to frontal COP excursion, it appears that subjects depend on the seat cushion and their legs and trunk strength during frontal excursion During the frontal reaching, the COP measures did not completely represent the trunk movement since part of the body weight is being transferred to the legs and then to the floor. Significant differences on the lateral COP excursion shows that during lateral excursion, the back and lateral components of the seating system were important because of the lateral trunk support, making the pelvis stable and allowing the subjects to perform better. The lateral Root Mean Square (RMS) of the COP shows that there is more deterioration in the lateral COP excursion when the scooter is used during a longer task (elliptical path task). Results showed that, even though there are no differences regarding upper extremity function and trunk frontal and lateral excursion, differences can be found on measures related to the basis of support when sitting, such as lateral RMS of the COP and leg deviation angles, this is, the interface between the body and the seat cushion. 116

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As mention in section 1.4.2.1, a subjective study33 was also performed during this study, showing that subjects felt a lower perception of exertion and less fatigue in the wheelchair. These two approaches showed that there was a difference between measured and asked performances. Even though subjects with MS expressed a difference between the seating systems, measurements did not show any differences. No differences were found in the order performed comparison regarding the group of subjects with MS. It can be concluded that the results of the study were not positively or negatively affected by a learning effect or a fatigue effect. 6.3 Recommendations Longer evaluations or continuous evaluations on separate days may have been more useful in order to appreciate long-term differences A continuous testing of the same subject will also contribute to understand how the progress of the disease will affect the performance. Performing these same tasks on a flat surface would complete the information for this study in order to observe the performance with a less challenging situation and use the same subjects as their own control. In addition to measuring the pressure distribution on the body-seat interface, measuring forces at the seat back and at the feet are needed This data will contribute to a better understanding of how the forces are being distributed during the task. This will also help to the implementation of a complete human body model because all external forces would be known. Since trunk calculations did not pick the differences 117

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on trunk excursion, an implementation of a more complex trunk template is needed. Advanced marker set should be used for further studies. All equipments used should have similar sample rates so data can be used appropriately. Since the symptoms of MS are very variable, it is necessary to test people with the same level of the disease to eliminate the fact the performance was highly affected by the disease and not by the seating system. As seen in Figures 5.26 and 5.27 some subjects with MS have better performance than some subjects from the comparison group. Future studies should include the analysis of subjects that have the same scale and its comparison to groups that have different scales. An improvement for the study would be having an equal number of persons with the same level of the disease using a customized and non-customized seating system as a primary mobility aid. A larger sample size might have produced more significant results. The population used should be expanded to other groups with MS, that way a better picture of how the seating system influence on the subject can be seen. 118

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APPENDIX 119

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Appendix A. Colorado Multiple Institutional Review Board This Certificate of Approval was obtained in order to perform the study. This document was reviewed and approved by institutions as the University of Colorado Hospital, the University of Colorado Health Sciences Center and the Veteran's Administration Medical Center. 120

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./ Colorado Mulipe lll$lllu1ional Review Board 13001 E. 17111 Place Building 500. Rcom N3214 AurGra, Colorado 8001Gon38 IJrlivaq;ityctCdlndo Hospllal DenWI'Hti1111IIOdiCIICOnlllr Vl!lllllan' tltdmmiltaliOn MeditaJ cen:tar n.Chi"""''IH01pi111 H..,., liel..-Cen!O< C""nrdoP-ClfOet Cortiflc:ate of Approval Investigator: OONNAJ BLAKE M1U!ng Adclfep : MaU 1'-490 P.O.II<>Ic6508 Au10111, Colorado Sponsor: VETERANS ADMINISTRATION MEDICAL RESEARCH Subject: [303) 724-1055 lP'!ooe) (303) 724-0D90 com/,__udlsc.edu JWehl lE-iiJ Assurance Ml ( i r:r:t.:rr1 h,r,:rtl C,n .. r.lt t,::f ll COMIRB Protocol 02-219 Initial RBYiew (APP001) 2ridRavlew CO/IOPAAISON OF UPPER EXTREMITY FUNCTlON II CUSTOMIZBl VERSUS NON.aJSTOYZEC &EATING Approval Date; Expiration Date: Approval Includes; 26AprU2003 Protoc:ol -Investigator-Conaent and/or A&eent Fonn -1 Quutlonnalre(s) .JI COIIIRB ApprvvH lrlvQtlgalarw must comply with 1ho following : For Oll'fcl\ange l nlho experllllental lmlolbe IIPI'ICiwd by tileb-.. inplementaUon oflhe cllangu. Use only a copy oflhe COMIRB -'fii!Cd and datarl Conaent and tor Assent Form. Tile lnv .. ligatnr beara II! a ruponsibilly for o-ing liom Ill subject& 'lnfollll!ld Ca...,nl" as OPPoEngllsllapo>klnQ ubjaels wllh a certlfltcllranolotion ollhe ;q>pruvorl Conunt andtor Assent Fo"" in the oubjocl'o flnllanguago. A copy of tho translator's ce111ficali011 sllculd be a/IKhtd to Ill& consanl andlor assent fcrm. Tho ilwatigOICI a lso the roll!anslblllly for lnf....,t ng 1ho CCIII IRS lmrnorllalol)' of anr Sorfouo Adverlle Evonta (dealhs, serious co. pticationl or Ol!ulr Wllow11d e1111dr> o1 the '""""rth at IIIIa .. other oi!M), and of the relalll>111hlp Df !he 3.\E 10 100 lnveotigallonal tr1aL The COMIR8 useo lhe standard delinlton of Serious or Un0111ldplled Evonla 11111 incltJo: deatll llo'llftll lzatlon prolongllllOn ol heap-allan a!ld oilier unenlir:ipated aide elflcla 01112il' COWRB approval for allarlwn1iemenlo llefore liM. FedMal ,.quire a Cornlnlllng RtvirlwiD.....,. approval of IIIIa project wBhln o 12..monu. pel1od !lorn"'"'"' ap-' dole unlou 0111.....m. indi<:alew. If 1"" have a re-.uilijjll rlok protocol, speciftc detds wiU be outrrned in this !oDor. Nan-cQIIIpll:lnee M!h Continuing Review 111111 resUlt in llle llmnlnll!ion of !Ills ollrdy. Thla prqoct has bee CNigroed the f-ing-cycle: COMIRB Continuing Review Cycle: 12 months We will send you v Continuing Reviaw Fonn u; be completed prier tc the dus tfale. Any qiiSSIIOil>i regarding UIO COMIRB aclioll on this 111rdy should be referred 10 the CCMIRB or UCfiSC So F-490. Stepben Blrtlelt RPh CMi r Jolorman H Stoller, DMD Co-CI>air Adom Ro11nberg, MD Clleir Cave Lawellin, PhO Co-CIIalr -01102 VA 121

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Appendix B. Veterans Affairs Research Consent Form Participants were asked to read and understand the content of this document prior to testing. This document gave the subject a brief explanation of the study objectives and procedures. Risks, reimbursements and conditions of the study are mentioned in this consent form. In case of questions, medical personnel were ready to explain and clarify the content. After understanding the subjects were asked to give their consent by signing the document. 122

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.-.. VA RESEARCH CONSENT FORM COLORADO MULTIPLE INSTITUTIONAL BOARD Approved CONSENT FORM APPROVAL JUN 12 COMIRB COMIRB PROTOCOL# 02-219 PRINCIPAL INVESTIGATOR: Donna Jo Blake, MD STUDY TITLE: Comparison of Upper Extremity Function In Customized versus Non..Customizecl Seating Systems Purpose You are being asked to take part in a research study comparing two different seating systems for people with multiple sclerosis. You are being asked to be in this s11Jdy because you have multiple and use a power wheelchair/scooter for getting around. The lnfonnation from this study will show us how a wheelchair fitted especially for you helps you do everyday activities compared to a scooter that Is not fitted especially for you. This research wili help doctors and physical therapists order wheelchairs for people with multiple sclerosis. There wnl be thirty subjects entered into the study from the Denver Veterans Affairs Medical Center. Procedure:; If you agree to take part in this study. no changes will be made In your current scooter or wheelchair after the study is complete. In addition, no changes will be made In your current care through Physical Medicine & Rehabilitation Services at the Denver Veterans Affairs Medical Center. Being In this study will take about 4 hours of your time and will require that you travel to the Human Performance laboratory located at the University of Colorado Health Sciences Center Fitzsimons Campus, Building 500, East Ground Rooms EG309 and EG 310, Aurora, Colorado. Before testing, a physical therapist will take measurements of your body with a tape and you will be weighed. Markers that reflect light will be attached to your body or clothes. You will be tested in a motorized wheelchair and in a scooter. You will be assisted with transfers in and out of the wheelchair or scooter by a physical therapist There will be two positions in which you will be tested. The first condition will be on a flat surface. You will be tested in a motorized wheelchair aRd also in a scooter in the flat position. You will do four tests in this position. Those tests will include: {1) reaching as far as you can forward and to the side, {2) moving your arm in a circular pattern (30 circles), (3) stacking five empty ... fast as you can and (4) reaching as far as you can forward and to the side. Once you have fiWMiE!"d'liiT'the tests in the wheelchair, you will be moved to the scooter to do the Version Date: 4/9/02 JUN 1 2 Valid Through: Subject Initials __ hlau:JYAfonn IC .. IOI6 123

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---Dqwrtrnl'lll ur \ \fl':is VA RESEARCH CONSENT FORM same tests. The order of whether the wheelchair or scooter will be first or last wilf be decided by the research staff. Once you are done with these tests In a flat position, you will be moved in your wheelchair onto a ramp that will tilt you 1 0 degrees to the side. During each test, your wheelchair will be locked down safely to the ramp. A safety belt will be placed loosely around your waist to keep you safely seated. You will repeat the same four tests In this position. Those tests will include: {1) reaching as far as you can forward and to the side, (2) moving your arm in a circular pattern (30 circles), (3) stacking five empty soda cans as fast as you can and (4) reaching as far as you can forward and to the side. Once you are done with all the tests In the wheelChair, you will be moved to the scooter to do the same tests. The scooter will be moved to the ramp and wnl be locked down. The safety belt wUI be placed loosely around: your waist to keep you safely in the seat. The order of whether the wheelchair or scooter will be first or last will be decided by the rasearch staff_ You wBI be given time to rest between each test and betWeen sitting in the wheelchair or scooter. You will also be given time to get used to sitting in the new seating system. During the testing, your activities wiD be filmed In order to analyze your body movements. We will measure the time it takes you to do thecan-stacking test with a stopwatch, and we will place a mat under you to measure the pressure on your buttocks for each test in both the wheelchair and the scooter. Risks and Discomforts There are risks and possible discomforts to you as you take part in the study. The markers are held onto your arms with tape, which can cause skin irritation. You are being asked to do .some physical exercise and you may get tired. You can stop at anytime during study if needed. There could be risks associated with this study that could not be expected ahead of time. There wm be a licensed physical therapist present at the study. You can direct your queslions to Dr. Donna Jo Blake at (303) 393-2819. C08ts1Relmburumant If you choose to take part In this study, there will be no cost to you. You will be paid up to$ 50.00 for being in this research study. You will be paid based on how much of the study you complete. You will receive $25.00 for completing the physical examination and the first test You will receive a second $25.00 for completing the second test You will have to pay for your own parking and costs for transportation. Benefits mentioned In the Risk Section above. Alternative Treatment Version Date: 4/9/02 Valid Through: Subject Initials __ 10-l086 REVISED Page 2of2 124

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--------------l.lcp;u I men! ot: \:clcr;ll\s All'air' : VA RESEARCH CONSENT FORM Funding All funding for this study will be provided by Veterans Health Administration, Rehabilitation Research & Development, Centers of Excellence Program as part of Center of ExceUence for Wheelchairs and Related Technology (WaRT), Pittsburgh, PA. StudyWithdrawal Taking part in this study is voluntary. You have the right to choose not to take part in this study. If you do not take part In the study, your doctor will still take care of you. You will not lose any benefits or medical care to whlc:ti you are entitled. I If you choose to take part, you have the right to stop at any time. If there are any new findings during the study that may affect whether you want to continue to take part, you will be told about them. The study doctor may decide to stop you from being in the study without your permlssion,lf he or she thinks that being in the study may cause you harm, or for any other reason. Also, the sponsor may stop the study at any time. a participant in the study, you may be taken out of the study by the investigators If the data cannot be collected. Injury and CompensaOon The Denver VA Medical Center will provide necessary medical care and treatment for any Injury that Is a result of being in this study. Compensation for such an injury may be permitted by applicable federal Jews and/or regulations. In order for this policy to remain in effect, you must comply with the study directions. lnvltaUon for Questions You will receive a copy of this consent form. Please ask questions about any aspect of this research or this consent either now or In the future. Yciu can direct your questions to Dr. Donna Jo Blake at (303) 393-2819. ln addition, if you have any questions about your rights as a research participant, please call the Colorado Multiple Institutional Review Board (COMIRB) office at (303) 724-1055. Confidentiality Your doctor, therapists, and research staff will treat your Identity with professional standards of confldentrallty. The consent form signed by you and your test results may be inspected and/or copied by: The U.S. Department of Health and Human SeNice The Colorado Multiple Institute Review Board Denver Veterans" Affairs Medical Center : Veterans Heafth Administration Center of Excellence for Wheelchairs and Related Technology (WaRT) University of Colorado Health Sciences Center Version Date: 419/02 Valid Through: Subject Initials __ 10 'REVISED 1 I 125

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--------------' llrpartoutnl nl ,\ll'.oit' National Committee for Quality Assurance VA RESEARCH CONSENT FORM Because of the need to relea!le lnfonnatlon to these parties, absolute confidentiality cannot be guaranteed The results of this research study may be presented at meetings or in publications; however, your name will not be revealed In those presentations. In case there are med i cal problems or questions, I have been told I can call Donna Jo Blake, MD at 303393-2819 during the day.and at 303-399-S020 x2289 after hours. If I have questioi"'S, complaints, or other concerns, I can also call the Colorado Multiple Institutional Review Board at 303-724-1055. A copy of this consent form wm be placed in my medical record. Signature:--=-=--:--------Print Name--------. subject Date ___ Consent form explained by: ----------'Print Name ______ Date. ____ Investigator ____________ Date _____ Version Date: 4/9/02 Valid Through: Subject Initials __ 10-1086 REVISED Page4 ol4 126

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Appendix C. Medical/Demographic Questionnaire This questionnaire was performed in order to have complete individual information about the subjects involved in the study. The data collected in this questionnaire was related to age, race, type of seating systems, and years using mobility aid, among other questions. Subjects were also asked about their medical condition involving their musculoskeletal, cardiovascular and fatigue issues. The scales used to measure perceived excursion and fatigue (the Borg Perceived Exertion Scale and the Fatigue Impact Scale) are also included in this appendix. 127

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:: Subject Identification #; .. Date; Medical/Demognmhic Questionnaire Subject Identification nwnber:. __________ GENERAL: .Age___yeiU'S Gender (circle one) male female Wei8}1t __ lbs. Race (check appropriate response) (1) Afro-American (2) Hispanic (3) Asian (4) Caucasian (5) American Indian (6) Other. __ (circle one) (I) Right _(Z)l.eft Approved JUH 12 COM1f1'8 How many years you have had the diagnosis of MS ___;yrs How many years have you used a manual wheelchair? yrs If you have used a scooter, how many years have you used a scooter? yrs If you have used a power wheelchair, how many years have you used a power wheelchair? yrs. Do you have any arm problems because of your MS? ___ YES, then what arm problems do you have? ________________ __ NO, I have no ann problems because of my MS. SOCIOECOMOMIC: What is your current employment status? I. Retired 2. Keeping house S. Unemployed 4. Employed If you are employed how many bourse per week doyou work? ____ _,hrs. What category best describes your total family income for last year, from all sources, before taxes? I. $20,000 or less 2. $20,000 to $50,000 3. $50,000 or above 128

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Subject Identification #: Date: 2. $20,000 to $50,000 3. $50,000 or above Are you CUJ."I.'ently: 1. Single 2. Married 3. Divored/Separated 4 Never married 5. Wuiowed 6. Other WHEELCHAIR: 1. Number of months or years in the current power wheelchair ----,------months/years. (please circle) 2. 'JYpe of current power wheelchair-------5. 'JYpc of current wlwclchair cushion 4. Is this power wheelchair your primary mode of getting around? YES NO If net, what do you we to get ____ 5. How many hours/day do you spend in your wheelchair?----SKIN: Have you ever had any skin breakdown on your buttocks or thighs? (circle one) YES NO If yes, where was the Howwu the breakdown treated?_ -----------Do you cUlTCntly have skin breakdown?_ ---------If so, where was the breakdown? ____________ MUSCULOSKELETAL: Have you had any problems with your shoulders? YES NO If so, what type of problems? ___________ Have you had any shoulder illjuries? YES NO If so, what type of injuries? ____________ If so, which Howhas your shoulder be treated? _____ 129 2

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Subject Identification#: Date: Have you ever had surgery on your shoulder? __ If so, which shoulder? __________ __________________________ __ CARDIOVASCULAR: Have you ever had a heart attack? YES NO When? Has your doctor given you. an activity limitation? YES NO If so, what is that limitation? ____________ Do you ever have chest pain? YES NO If so, with activity or without activity1 _________________ Do you use heart medications? YES NO If 50, what are the medications? ____________ Do you have asthma or emphysema? YES NO IF so, what medications do you use for this condition? ____ Do you have any physical problems associated with use of your power wheelchair? YES NO If YES, please explain _______________ EXERTION /FATIGUE: Borg Perceived Exertion Scale and Fatigue Visual Analog Scale after each test for a total of four times. 130 3

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Subject Identification #: Date: BorJ; Perceived Exertion Scale No Fatigue 6 7 very, very light 8 9 verylight 10 11 fairly light IZ IS somewhat hard 14 15 hard 16 17 veryhard 18 19 very, very hard 20 Fatipe Visual Analog Scale. Worst Possible Fatigue 131 .. 4

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Appendix D. Physical Exam and Anthropometric Measurements A physical exam on the upper limbs and trunk was performed on the participants. The exam involved the angular measurement of the Range of Motion of the upper limbs and the Manual Muscle Testing of upper limbs and trunk. Measurements on the subject bodies and mobility aids were also performed during this process. 132

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Subject Identification #: Date: Physical Exam and Anthropomorphic Measurement_, Weight of subject and wheelchair Obs>--:---Weight of wheelchair Obs) Distance from floor to top of head of subject sitting in the wheelchair (mrn) ___ ROM of Upper Extremity: (in degrees) RWtt Left SHOULDER Flexion Extension Abduction Adduction IR. ER ELBOW Flexion Extension WRIST/HAND Wrist flexion Wrist Extension Finger flexion (full grip orfunited) l'iitger extension (fully opened hand or limited) 133

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Subject Identification# : Date: Upper Extremity/Trunk Manual Muscle Testing: (0 with 5/5 = normal strength) RW\t left SHOULDER Flexors Extensors Abductors Adductors m: ER ELBOW Flexors Extensors WRIST/HAND Wrillt Flexors Wrist Extensors Trunk! Abdominals (ITO) Balance (0 1, 2) Pelvic Qbliguity; RIGEIT higher the LEFr higher than EQUAL LEFf RIGEIT Wheelchair Scooter Right l.cft Axillary Arm Circumference Elbow Circumference Wrist Ci.rcumference Upper Arm LeriS:th Forearm 2 134

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Subject Identification#: Wheelchair and CUshion Mea.urements: (in mm) Wheelchairback'-----------Wheelchair Cushion Width Depth Seat to Floor with cushion Seat to Floor without cU.won Top of cushion to t.ot' of back Subject Identification #: Greater Trochanter to HiptoKnce Knee to Foot 135 Date: Scooter Date: ..

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Appendix E. Procedures Two persons were involved with the data collection. One of them was directly interacting with the subject and the other person was in charge of managing the data acquisition systems. The prpcedures of these persons were related at some moments of the test, but at other moments they were totally independent. After the data collection was completed, the process of digitization was started on the measurement motion analysis system. The procedures for this process are also presented in this appendix. E.l Subject preparation prior to testing Prior to testing the subjects had to give their consent and get ready for data collection. Mobility aids were prepared also. The person who interacted with the subjects was in charge of all these activities, which were completed in a period of time of 45 minutes approximately. 1. Explain testing protocol and equipment to the subject. 2. Review consent-form with the subject; consent subject. 3. Weigh subject and wheelchair with subject in their wheelchair 4. Transfer subject from their wheelchair to a treatment table (2 people will be present for the transfer). 5. Provide medical questionnaire for subject to complete. 6. Weigh subject's wheelchair 7. Complete wheelchair and cushion measures; place reflective markers on wheelchair and scooter wheel axles. 8. View motion-capture monitors for any wheelchair and scooter reflections interfering with motion data collection and wrap tape around these reflective wheelchair surfaces. 9. Complete physical exam and anthropometric measures. 10. Place reflector markers on anatomical landmarks. 11. Place FSA pressure pad on cushion and prepare data acquisition system. 12. Transfer subject to seating system selected. 136

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E.2 Instructions given to subjects during testing The following instructions were given to the subjects during the test. The person who interacted with the subjects was in charge of giving the instructions. E.2.l Test 1: Lateral and Forward Reaching Task 1. Place hands on thigh, elbows on armrests. 2. When Peak operator says, "go", reach to side with the dominant hand as far as you can 3. Look towards each target when reaching. 4. Come back and place your dominant hand on thigh, then reach forward as far as you can towards target. 5. Come back and place your dominant hand on hand and repeat side reaching and forward reaching another four times. 6. Tester will count for you and will say, ... this is your last one and stop". 7 Put hands on armrests and perform a push up. E.2.1.2 Test 2: EUiptical Path Task 1. Place pen on dominant hand with the pen vertically sticking out of fist. 2. Make a circle around the reflective balls starting with the ball that is to the side. If the person is right handed the. movement is performed in the counter clockwise direction. If the person is left handed the movement is performed in the clockwise direction. 3. Do not hit reflective balls if possible. 4. You will do 30 circles in a row continuously (at a comfortable speed). If you hit a ball just keep going. 5. Tester will tell you when you have done 15, 20, 25 and then say "this is your last one ... and stop". E.2.1.3 Test 3: Can Stacking Task 1. Place your dominant hand on out side of last can. If the subject is right handed place it to the right side of the cans. If the subject is left handed place it to the left side of the cans. 2. When tester says, "go", pick up the cans one by one and place them on board as quickly as possible. If a can falls over on board, leave it and move on to the next can. 3. This test is timed. 4. The test is finished when the last can is placed on the board. 137

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E.3 Data Collection Procedure The person in charge of the data collection equipment followed these instructions. This person gave the order to start for each task and it was in charge of checking that the data was satisfactory collected. E.3.1 Prior to testing: 1 Locate and adjust cameras in position to catch the seating system and the subject. Take care of the size of the subject 2. Locate the calibration device: star and frame. 3. Adjust cameras to catch the calibration device: orientation, zoom and focus. 4. Check that all cameras are displaying the triggering window on the upper left comer of the screen. 5. Align Tapes. 6. Install the box to synchronize the Peak and FSA system. Install the wiring for power supply, and Peak. The cable to the FSA remains unplugged (remote trigger). 7. For the FSA, connect the serial port cable from the computer into the box. 8 Check the trigger button for the Peak System. A thicker line must appear on the triggering window when it is being pressed. 9 Open aperture and record the calibration video (30 seconds) 10. Close aperture to capture the markers only. 11. Tum off room lights and tum on camera lights. System is ready to collect. 12. Write down the time when the subject is sitting. 13. Be aware of push up after 5 minutes. Start trial after 5 minutes from the push up. E.3.2 Prior to each Task: 1 Create a new file for the FSA and choose remote setup. 2 Press the FSA off button to tum off the signal. 3 For the FSA, unplug the cable from the computer and connect the remote trigger cable. 4 One minute before the task put all the VCR in record mode and right after that in pause mode. 5 Start recording ten seconds before the test begin. 6 Five seconds before start the countdown. 7. Press the trigger button when 1 second is left. 8. Give order to start. 138

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E.3.3 During the Task: 1. Check that all VCRs are in the recording mode. 2. Check that red light is blinking in the FSA box. E.3.4 Subsequent to the Task: 1. Write down the time 2. Stop all the VCRs. 3. Ask for push up. 4. Write down the time. 5. Add 5 minutes to the next task. 6. Switch cables in the FSA box. 7. Start download from FSA. 8. Save file. E.4 Digitization Process using the Peak Motus System In order to reduce the data collected and prepare for further analysis, a digitization process was performed. 1. Check that the computer has at least 200MB of memory free. 2. Open the Peak Motus program. 3. Define the spatial model: markers, segments, virtual points, angles, and parameters to be used during the experiment. 4. Upload videos from the calibrating device. Calibration video files should have only 2 frames. 5 Identify all markers from this device on each camera. 6. Create a template if necessary. 7. Upload videos of the trials into the computer. 8. Be sure that all the trial and the synchronizing signal is included in the video files and then proceed to trim the videos. 9. Identify all the markers that can be viewed on each camera Define these as moving or stationary. 10. Proceed to digitize using the frame-by-frame mode. 11. Once the digitization process is done, check if there is any gap. If, so switch to marker mode to work exclusively on the markers that have those gaps. 12. Create a template for calculations and then run it. 13. Go to the results tab and copy the results into an Excel file in order to facilitate the data transfer to other computers. Motus usually crashes after this procedure so it is recommended to save the file continuously. 139

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Appendix F. Triggering Device This device was utilized to start the data collection of the two systems at the same time, so data could be synchronized. Additionally, this device allowed pressing the triggering button of the video system along the test without affecting the data collection on the FSA system. The wiring of this device is shown in Fig F .1. Triggering Button ---""!-------.., DPST momentarily To Peak c D FSAbutton .-----------+ 5V 1 I Dual Coil Latching Relay ----------------------, X SPST momentarily DPST: Double Pull Single Throw. SPST: Single Pull Single Throw. Figure F.l. Wiring of the Triggering Device 140 ToFSA

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The triggering button was utilized to send a signal to the Peak system by closing the circuit between the ends A and B. At the same time the ends C and D were also connected and a signal was sent through the Dual Coil Latching Relay. When that happened the switch that was connected to the end Y, was immediately connected to the end X sending a signal to the FSA system to start the collection. If the triggering button was pressed again the signal was sent to the Peak system without affecting the FSA collection since the switch was kept on the X end. Only if the FSA button was pressed the switch returned to its original position on the Y end. Because of that the FSA button was pressed at the end of each task, so the system was ready for another data collection. 141

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Appendix G. Marker Locations The marker locations were based on the neutral position of the hwnan body, this means having the palms of the hand facing the anterior or frontal view. Figure G.l shows the locations of the markers on the right side and the orientation of the medial and lateral directions. Regarding the extremities, the medial direction is towards the body and the lateral direction is outwards the body. The markers were located at the bony protuberances in order to minimize the effect of the skin movement. Acromiwn Lateral Elbow Medial Elbow Lateral Wrist Medial Wrist Knee Ankle \ \ \ .. \ ... Lateral \ Direction Medial Direction Figure G.l. Anatomical Landmarks. 142

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The exact locations of the bony protuberances are shown in the next figures A trained physical therapist located these locations by palpation and attached the markers to the skin using double-sided tape G.l Acromium Markers This marker was located on the shoulder area. Specifically, it was located at the acromium process of the scapula bone Figure G 2 shows the location of the marker on the right side of the body. Right Acromium Marker Humerus Acromium Process Sternum Figure G.2. Anterior (Frontal) View of the Right Acromium Marker G.2 Elbow Markers These markers were located on the lower end of the humerus bones. Specifically, they were located on the lateral and medial epicondyle of the humerus. Figure G 3 shows the exact locations of the markers on the right humerus 143

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Right Humerus Lateral Epicondyle Right Lateral Elbow Marker Medial Epicondyle Figure G.3. Anterior (Frontal) View of the Right Elbow Markers. G.3 Wrist Markers These markers were located on the lower end of the radius and the ulna bones Specifically, they were located on the radial and ulnar stylod processes. Figure G.4 shows the exact locations of the markers on the right wrist. Right Radius Radial Stylod Process Right Lateral Wrist Marker -+---Right Ulna Ulnar Stylod Process Right Medial Wrist Marker Figure G.4. Anterior (Frontal) View of the Right Wrist Markers 144

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G.4 Greater Trochanter Markers These markers were located on the upper end of the femur bones. Specifically, they were located on the greater trochanters Figure G 5 shows the exact locations of the marker on the right greater trochanter G.S Knee Markers These markers were located on the lower end of femur bones. Specifically, they were located on the lateral condyle. Figure G 5 shows the exact locations of the markers on the right knee. Right Greater Trochanter Marker Greater Trochanter Lateral Condyle Right Knee Marker 1--++---Right Femur Figure G.S. Anterior (Frontal) View of the Right Greater Trochanter and the Right Knee Markers. 145

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G.6 Ankle Markers These markers were located on the lower end of fibula bones Specifically, they were located on the lateral malleolus. Figure G. 6 shows the exact location of the marker on the right ankle Fibula Lateral Malleolus Right Knee Marker Tibia Figure G.6. Anterior (Frontal) View of the Right Ankle Marker. 146

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Appendix H. Tilted Surfaces The following are the drawings corresponding to the tilted surfaces mentioned in section 3.2.4. Initially the specifications of the main ramp are presented and after that, the specifications corresponding to one auxiliary ramp are also presented. 147

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''Ir\: V.r. ... VJ 47.50 All coMponents Ct'E' joint by screws C""Drll\IT \/IE\ I : i'.Ui\1 V '-tV DiMensions in inches UNIVERSITY OF COLORADO AT DENVER MASTER THESIS DRAFTER F. CASTRO MAIN WOODEN RAMP ADVISOR R.A.L. RORRER SIZE I QUAJIITJTY I 11 DATE 05/20/03 A4 1 FIGURE H.l CHECKED I APPROVED SCALE 1:10 I I DRAWING 001 148

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I I l.:iD -L rl-1.50 MASTER THESIS DIW'TER F. CASTRO ADVISOR R.A.L. RORRER DATE 05/20/03 CHECKED I APPROVED r .;;.l -SIDE VIEw "1 ( 7 ?.3) Jo ___j_ I I -j 3.25 "t...r:-I Tifl'l-i 0 ,_..I\ r l. UNIVERSITY OF COLORADO AT DENVER MAIN WOODEN RAMP SIDE VIEW, SECTION A-A SIZE I QUANTITY A4 1 I Figure H.2 11 SCAlE 1:10 I I DRAWING 002 149

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-.. -'"'''"----.. -........................ ______ .. ,_,,, .............. ...... --57. 98 ------..................................... .. !-......................... ................................ I l i l : : i TOP VIEw Dir"lens.ions in incles. r"E .. 6R-\iTE"'\i f'< .... fl Vi .... 'IV 2 00 J 3.50-' i All cof"'lponents o.re join t by screws I l UNIVERSITY OF COLORADO AT DENVER MASTER THESIS DRAFTER F. CASTRO AUXILIARY WOODEN RAMP ADVISOR R.A.L. RORRER SIZE I QUANTITY I Figure H.3 11 DATE 05/20/03 A4 2 CHECKED I APPROVED SCALE 1:10 I I DRAWING 003 150

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r.PL Y\NOOD t 0.75 f I .... J 1 ...................... I ....... .._.,_,__ .. I -------. t i I : I 6.?8/ _!__ I 1--eno--..... : \ I"' .--\ I 1---.l .l.J t.. ./ 1. t .. w 18 00---1 1------28.()()------1 BOTTOM VIEw --1 I 1-!.50 --111---UNIVERSITY OF COLORADO AT DENVER MASTER THESIS AUXILIARY WOODEN RAMP DRAFTER F. CASTRO SIDE AND BOTTOM VIEW ADVISOR R.A.L. RORRER SIZE I QUANTITY l Figure H.4 11 DATE 05/20/03 A4 2 CHECKED I APPROVED SCALE 1:10 I I DRAWING 004 151

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Appendix L Peg Holder The specifications for the two peg holders mentioned in section 3 .2.5 are presented in this appendix. 152

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DET All A '72.00 1 t-3 .2 5 i i _L_ .----1.50 ..J A r---.. -u-// I ......... MASTER THESIS DRAFI'ER F. CASTRO ADVISOR R.A.L. RORRER DATE 05/20/03 CHECKED I APPROVED '"-. \ \ DET A l l B l \ UNIVERSITY OF COLORADO AT DENVER PEG HOLDER -LATERAL VIEW SIZE I QUANTITY A4 2 I Figure I.l 11 SCALE 1:20 I I DRAWING 005 153

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co1"1por.ents joint by screws / \ \ \ ; DETAIL C .; I \ I 98.25 I 1n inches UNIVERSITY OF COLORADO AT DENVER MASTER THESIS DRAFTER F. CASTRO PEG HOLDER FRONTAL VIEW ADVISOR R.A.L. RORRER A41 QUANTITY 2 I 11 DATE 05/20/03 Figure 1.2 CHECKED I APPROVED SCAli: 1 ;20 1 I DRAWING 006 154

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---l9.00---l ro.so MASTER THESIS DRAn'ER F. CASTRO ADVISOR R.A.L. RORRER DAn: 05/20/03 CHECKED I APPROVED -..... j t .... ......, .......... -.:.: .. ------.. t t -l ? / 20.00 / 1.00 UNIVERSITY OF COLORADO AT DENVER PEG HOLDER -DETAIL A SJZE J QU.ANTITY A4 2 I Figure 1.3 11 SCALE 1:10 l I DRAWING 007 155

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[ "'"" .. !_ ) .. .. J ;:--"} /\\ I 2 C)t:_,/ \ \ v \ \ 1.00- -JI-oo .-r\ / \ \ \ \ 33.30 \, \ --30" 28.00 40.00--.1i ---------\ ----1 \ i I 1 --r -----_J I :woj--,_...__ ___ D inensions in inches UNIVERSITY OF COLORADO AT DENVER MASTER THESIS DRAYI'ER F. CASTRO PEG HOLDER -DETAIL B ADVISOR R.A.L. RORRER SIZE I QUANTITY I Figure 1.4 11 DATE 05/20/03 A4 2 CHECKED I APPROVED SCALE 1:10 I I DRAWING 008 156

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1.00 MASTER THESIS DRAFTER F. CASTRO ADVJSDR R.A.L. RORRER DATE 05/20/03 CHECKED I APPROVED 1.50 -----i 20.50 i i I \ > D11"le>nsions ir. inches i 1.00 l UNIVERSITY OF COLORADO AT DENVER PEG HOLDER -VIEW FROM A-A SIZE I QUANTITY A4 2 I Figure 1.5 11 SCAlE 1:10 I I DRAWING 009 157

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11'--0.75 DETAIL C lll0.25 3.00 SEC TID\ B-B I 1----1.50 I 5.00 i !------------------------41.50 ----------------! SCALE: J :SO DiMensions in inches UNIVERSITY OF COLORADO AT DENVER MASTER THESIS PEG HOLDER DRAn'ER F. CASTRO DETAIL C AND SECTION B-B ADVISOR R.A.L. RORRER SIZE I QUAN11TY I Figure 1.6 11 DATE 05/20/03 A4 2 CHICXED I APPROVED scm: SHOWN I I DRAWING 010 158

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Appendix J: Individual Data for the Seating System Comparison J.l Results from Subjects with MS J.l.l Lateral and Forward Reaching Task Table J.l. Lateral and Forward Reaching Task Results from Subjects with MS. Seating System Comparison. Average Trunk Flexion/Extension Angle Average Lateral Trunk Flexion/Extension Maximum Trunk F l exion/Extens ion from Vertical C"l An!le(") An lel"l Subject Wheelchair Scooter Wheelchair Scooter Wheelchair Scooter Initial Finel Initial Final Initial Final Initial Final Initial Final Initial Final Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach 1 -12.3 -0.5 -1.0 -0 5 5 9 1.7 3.0 7.2 -5.6 8.5 5 0 4.0 2 1.9 -1.8 3.1 1.1 18 1 14.6 16.9 16.5 28.4 18 1 31.0 29.2 3 -0.7 1.1 0 2 -0 6 14.8 13 0 13 3 12.4 32.8 31.1 31. 3 32 0 4 -4.4 -5.0 0 0 2 1 10 1 8 5 9.2 8.8 12 9 10.2 14 1 9 .6 5 3.7 5 3 3 7 6 4 10.5 14 6 10.0 15.4 10.1 20 7 10 1 24 4 6 18.3 22.4 26 6 23 4 5.8 6.3 11.2 10 3 45.8 47.8 51.3 47 9 7 -27 0 -27.2 -4 7 -19 8 3.3 4 5 5.0 15.1 21.0 20.3 -5 5 13 8 8 -5 4 -6 3 -7 6 -9 3 8 6 6 3 7.5 8.8 26.0 17.7 12 6 8 2 9 15 8 19.2 20 8 15 1 11. 0 10 9 16.5 14.5 42 8 43 6 40 0 43 7 10 12.3 9 8 9 4 11. 8 5 4 3.3 8 1 3 9 28.6 21. 5 19 0 23 6 Results Avera_g_e 0.2 1.1l 5 .01 9 .41 8.4 10.1 11.3 24 3 23.9 20 9 23 6 Sid Dev _I 13 .71 14.01 10 .91 12 .41 4 .61 4 7 4 6 4.1 15.5 13. 1 17 3 14 9 Skewness I -0.5871 -0.5221 1.1181 -0.0731 0 674 0 114 0.162 0 674 0 114 0 162 -0 383 Comparison p-values Initial to Final Wheelchair to Initial to Final Wheelchair to Initial to Final Wheelchair to Reach Scooter Reach Scooter Reach Scooter Wheelchai Scooter Initial F inal Nheelcha i Scooter Initial Final Nheelchai Scooter Initial F inal Parametric: TTest 0.312 0.156 0 076 0 438 0 237 0 386 0.468 0.021 0.892 0.314 0 340 0 869 Non-Parametric: 0.445 0.169 0.074 0.575 0 169 0.646 0.646 0.009 0.799 0.575 0.441 0.959 Wilcoxon 159

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Table J.l. (Cont.) Lateral and Forward Reaching Task Results from Subjects with MS. Seating System Comparison. Maximum lateral Trunk Path Length (m) Lateral Reaching Rallo Flexion/Extension Angle(") Subject Wheelchair Scooter Wheelchair Scooter Wheelchair Scooter Initial Final Initial Final Initial Final Initial Final Initial Final Initial Final Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach 1 16.6 9.8 9.0 13.5 13.6 13.8 12.8 13.1 0.96 0.93 1.00 0.95 2 35.0 31.3 37.0 35.9 18.9 19.5 18.9 19.3 1.10 1.02 1.18 1.11 3 38. 9 35.3 32.3 29 6 16.3 18 4 15.7 16.1 1.20 1.14 1.14 1.05 4 21.1 20.9 19.6 18.0 17.5 15.7 15.2 17.1 0.78 0.43 0.48 0.74 5 21.3 29.9 20.9 28.4 14.5 14.9 14.3 15.9 0.67 0.72 0.67 0.75 6 34. 5 35.5 38 3 34 9 16 5 14 8 15 3 15.3 0 98 0 90 0 95 0 89 7 10.8 12.9 9.1 21.8 11.8 11.6 12.1 11.8 0 .88 0.86 0.80 0.74 8 34.6 29.3 32.6 21.3 17.3 16.4 16.0 15.1 1.30 1.21 1.10 1.10 9 36.4 35.8 36.4 33.4 18.2 18.1 15.5 16.6 1.16 1.20 1.20 1.16 10 18. 1 16.6 19.8 15.1 19 1 16 4 13.8 14.2 1.12 0.99 0.86 0 .88 Results Average 26.7 25.71 25 .31 25 .21 16.41 16.0 15.0 15.4 1.01 0.94 0 .941 0.94 SldDev 10.11 9.8 11.0 8.31 2 .41 2.4 1.9 2.1 0.20 0.24 0.241 0.16 Skewness 0 874 0 114 0 162 .383 .c.823l -C.276 0.628 .0.032 .0.408 .014 -C.736 .0.019 Comparison p-values lniUallo Final Wheelchair to Initial to Final Wheelchair to Initial to Final Wheelchair to Reach Scooter Reach Scooter Reach Scooter Wheelchai Scooter Initial Final /Vheelcha Scooter Initial Final Wheelchai Scooter lniUal Final Parametric: T-Test 0 498 0 966 0.206 0 738 0 379 0 106 0.025 0.233 0.057 0.946 0.095 0.937 Non-Parametric : 0 333 0 .721 0.373 0 646 0.445 0 139 0.017 0 .241 0 037 0.515 0.155 0 475 Wilcoxon Table J.l. (Cont.) Lateral and Forward Reaching Task Results from Subjects with MS. Seating System Comparison. FOIWald Reaching Ratio Frontal COP RMS (m) Average of Maximum COP Frontal Displacement {m) Subject Wheelchair Scooter Wheelchair Scooter Wheelchair Scooter Initial Final Initial Final Initial Final Initial Final Initial Final Initial Final Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach 1 1.02 1.01 1 00 1.02 0 004 0.003 0.003 0 005 0.007 0.009 0.012 0.018 2 1.47 1.41 1.52 1.54 0 020 O.D19 0.018 0.026 0.036 0.048 0.051 0.072 3 1 56 1.52 1.57 1.49 0.021 0.017 0.035 0.019 0.088 0.058 0.104 0.055 4 1.34 1.22 1.25 1 25 0 007 0 006 0.010 0 005 0 024 0.014 0 007 0 004 5 0 70 0.87 0.70 0.82 0.005 0.009 0.015 0.007 0.009 0.022 0.031 0.017 6 0.96 0.87 0.86 0.88 0.024 0.009 0.027 0.029 0.083 0.097 0.079 0.090 7 0.96 0.90 1.04 0.88 0.006 0.006 0.007 0.006 0.026 0 022 0.008 0.019 8 1 60 1.48 1.27 1.31 O.ot8 O.Q16 0.006 0 007 0 .071 0.053 0 024 0.006 9 1.57 1.59 1.53 1.55 0.022 0.024 0.021 0.025 0.061 0.076 0.050 0.060 10 1.17 1.11 1.16 1.10 0.004 0.005 0.004 0.006 0.009 0.011 0.005 0.008 Results Average 1 23 1.20 1.19 1.18 0 013 0.011 0.015 0.014 0.039 0.041 0.037 0.035 Sid Oev 0 32 0 28 0 30 0 28 0.008 0.007 0 .011 0.010 0 029 0.030 0.034 0.032 Skewness -C.317 0 120 -C.181 0 094 0 071 0.594 o.m 0 65f!l 0 297j 0 666 0 997 0 700 Comparison p-values Initial to Final Wheelchair to Initial to Final Wheelchair to lniUal to Final Wheelchair to Reach Scooter Reach Scooter Reach Scooter WheelchBJ Scooter Initial Final Wheelchai Scooter Initial Final Wheelchai Scooter Initial Final Parametric: T-Test 0.225 0 858 0.245 0.540 0 346 0 .621 0 508 0.401 0 686 0 752 0 762 0 327 Non-Parametric: 0.114 0 952 0.260 0.357 0 402 0 959 0 439 0 .371 0.575 0 919 0.799 0 .201 Wilcoxon 160

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Table J.l. (Cont.) Lateral and Forward Reaching Task Results from Subjects with MS. Seating System Comparison. lateral COP RMS (m) Average.ot Lateral Distance from Mid A=mlum to Mid GT (m) Subject Sa oter Sccoter :!':! :!:1 O.D19 D.542 D 538 0 0.521 D.D58 1143 D.592 D 620 0. D.64l D D. D6 D .59!1 0.581 0 .0.57: D 039 D.61' ) 616 D D.f13E D 030 D7: D 55( 1 545 0 5 D.SIE D.D37 0.51' ),507 0 5 0.491 .DO D.DD9 09 D.57 ) ,571 0.607 0.571 .D3 O .D8D 57 .1' D.60! ).594 0 .5611 0.561 .02 D.D62 59 ) ,II! 0 58: .0.58.1 D. I.D15 O.D34 23 D. DO: D.58' D.550 0.584 0.552 lesults lverage I .D171 D.D201 D.D221 I.D191 _0.0471 0 .0471 0.0521 D.0451 0 .5751 0 ..6!11 0 .5761 0.573 itdDev 1.0101 O .D111 0 0131 0 .0121 0.0291 0 .0261 0.0411 0 .0381 0.0311 0 ,0361 D .0381 0 .045 .7941 -0.261 0.3561 D.6461 0.8291 -0.0371 -0.0731 I.D321 D.701 -0.1391 -0 .2021 0 226 Comparison p-values Saoter Sec oter v Scooter u Scooter Initial Final Scooter Initial Final Scooter Initial Final Parametrlc: T-Test D 237 D.D96 0.144 0.926 0 922 0.219 0.634 0.818 0.241 0 635 0.906 0.607 Wilcoxon 0 .476 0.063 0 260 1 .000 0.515 0.262 0.799 0 441 0 .059 0.575 0 859 0.575 Table J.l. (Cont.) Lateral and Forward Reaching Task Results from Subjects with MS. Seating System Comparison. Height from Wrist to Shoulder (m) Trunk Leg Angle (") Knee Angle (") Subject Wheelchair Scooter Wheelchair Scooter Wheelchair Scooter Initial Final Initial Final Initial Final Initial Final Initial Final Initial Final Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach 1 0 102 0.102 0.107 0.137 69.5 83.8 86 0 86 0 75.1 71.0 90.8 88.3 2 0 083 0.083 0 094 0 100 95 5 94 5 98 1 97.2 96.6 98. 3 93.5 93. 9 3 0 .161 0.138 0.118 0.160 85.2 85.1 84.1 82.3 95.4 95.8 97 6 96. 4 4 0 193 0.205 0.194 0.213 81.6 80.3 81.8 78.3 57.8 68.1 85 8 87.2 5 0.233 0.249 0.233 0.263 70.4 70.5 78 5 76.7 52.1 47.5 58.3 84.4 6 0 252 0 229 0 241 0.217 89.0 89.6 102.7 100 0 79 4 77.7 94 2 95 3 7 0 002 -0.002 -0.116 0.014 79. 2 78 3 86. 7 84.8 84.7 83.2 104 5 92.1 8 0 139 0.137 0.117 0.129 82.2 82 0 86. 1 82.7 67.4 68.2 105 4 104 3 9 0.208 0.209 0.206 0.204 91.6 94 4 92 5 92.3 67.9 62.7 96 6 94.3 10 0 194 0.192 0.206 0.197 80,7 78. 3 77.5 70 2 61.4 75.6 91. 4 88.5 Results Average 0 157 0.154 0.140 0.163 82.5 83 7 87 4 85.1 73.8 74.8 91. 8 90.5 StdDev o on 0,078 0.106 0.072 8.4 7 6 8.1 9.3 15.3 15.2 13 2 10.4 Skewness -0.840 -0.800 -1.698 -0.859 -0. 176 0.021 0.781 0.230 0.268 0 .001 -1. 986 -1.803 Comparison p-values Initial to Final Wheelchair to Initial to Final Wheelchair to Initial to Final Wheelchair to Reach Scooter Reach Scooter Reach Scooter Wheelchai Scooter Initial Final VVheelchai Scooter Initial Final Nheelchai Scooter Initial Final Parametrlc: T-Test 0 533 0 118 0.211 0.081 0 451 0 007 0 039 0 433 0.618 0 395 0 002 0.003 NorrParametric: 0 400 0.074 0.343 0.083 0 760 0.008 0.047 0.445 0 919 0.333 0.009 0.009 Wilcoxon 161

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Table J.l. (Cont.) Lateral and Forward Reaching Task Results from Subjects with MS. Seating System Comparison. Angle Deviation Dominant Leg Non-Dominant Leg Subject Wheelchair Scooter Wheelchair Scooter Initial Final Initial Final Initial Final Initial Final Reach Reach Reach Reach Reach Reach Reach Reach 1 11.0 11. 4 3.5 -12.7 2.8 -2. 5 -3 0 -8.4 2 0.7 3 1 -3.3 -3.2 8.9 6.8 12.2 13.5 3 18. 1 21. 8 15.0 20.9 3.4 0.4 -4.9 -3.1 4 0 2 .Q. 8 7.3 9 2 11. 3 11.4 -17.7 -23. 8 5 -5 2 -7. 4 -8 0 -5.0 2.1 0 9 -5 1 .Q. 2 6 12. 5 16. 1 7.8 7.6 8.0 9.4 18.4 17.0 7 12.2 18.6 -2.0 17.1 -1.2 -2.7 -4.5 -15.8 8 6.3 8 3 18.3 22.4 3.7 5 3 13.3 7.3 9 -5.0 -1.8 -11. 0 -2.0 7.6 6 9 3.4 1 3 10 -3. 8 -7. 8 -3. 6 3.8 9 5 7 9 -13. 0 -19.7 Results Average 4 7 6 1 2.4 5.8 5.6 4.4 -{).1 -3.0 Std Dev 8 4 10.7 9 7 11. 8 4 .0 5 .01 11.71 13. 7 Skewness .Q.210 .Q.095 .{).350 .Q.OSSI .{).2161 .{).2651 0.2291 .{).116 Comparison p-values Initial to Final Wheelchair to Initial to Final Wheelcha i r to Reach Scooter Reach Scooter Wheelcnai Scooter Initial Final /Vheelchai Scooter Initial Final Paramelric : T-Test 0.188 0.255 0.347 0.928 0.092 0.088 0.185 0.133 Non-Paramelric: 0 .203 0.093 0.285 0 959 0 .103 0 .074 0.262 0 203 Wilcoxon J.1.2 Elliptical Path Task Table J.2. Elliptical Path Task Results from Subjects with MS. Seating System c ompanson. Average Trunk Average Lateral Flexion/Extension Trunk Path Length per Frontal COP Frontal COP RMS Subject Angle from Vertical Flexion/Extension Cyde (m) Displacement (m) (m) (") Angle{0 ) Wheelchai Scooter Wheelchai Scooter Wheelchai Scooter Wheelchai Scooter Wheelchai Scooter 1 9.8 7.6 5.1 3.2 1.15 1 24 0.006 0.002 0.009 0.004 2 6.7 0.1 22.2 21.5 2 .73 2 .56 0 .013 0.000 0 .026 0.007 3 11. 2 16.1 13.2 16 6 1 .70 1.71 0 003 0.013 0 010 0.025 4 15.2 0.9 36.7 12.6 1 .44 1 .41 O.D16 0.004 0.019 0.004 5 13.8 19.3 14.5 21.9 1 27 1 41 0.002 0.010 0.011 0.015 6 20.4 20.3 13.3 10.3 1 .66 1 85 0.025 0.029 0.043 0.029 7 19.7 3.7 10. 2 13 1 1 .04 0.95 0.007 0.002 0 .007 0 003 8 6.8 3.6 8.2 13.8 1.26 1.57 O.D15 0.001 0.016 0.010 9 28.7 29.0 18.3 24.3 2 .71 2.32 0 023 0.017 0.029 0.034 10 10.4 11.9 22.9 11.9 2 10 1 88 -0.011 0.017 0.012 0.005 Results Avera11e I 14.31 11.21 16.5 14.91 1.711 1 .691 0.0101 0.0091 0.018 0.013 Std Dev I 6.91 9.71 9.11 6.31 0.621 0.491 0.0111 0.0101 0.0111 0.012 Skewness I 0.9731 0 .5431 1 18 -0 .1541 -0 .5561 -0 137 -0 4641 0 .9261 -0.464 0.926 Comparison Parametric : TTest 0.224 0.625 0.805 0 931 0.200 Non-Parametric: 0 333 0 878 0.838 0 610 0.575 Wilcoxon 162

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Table J.2. (Cont.) Elliptical Path Task Results from Subjects with MS. Seating System Comparison. Lateral COP Lateral COP RMS Distance from Mid Height from Wrist to Acromium to Mid GT Trunk-Leg Angle {0 ) Subject Displacement (m) (m) (m) Shoulder (m) Wheelchai Scooter Whee lcha1 Scooter Wheelchai Scooter Wheelchai Scooter Wheelchai Scooter 1 0.011 0.009 0 015 0 013 0 602 0 562 0.198 0.413 95.5 91.2 2 0 046 0 020 0 048 0 012 0.623 0.603 0 194 0 .449 101.7 95 3 3 0 053 0.028 0 060 0 016 0 634 0 629 0 200 0 369 92.7 97 3 4 0 047 -0 005 0 050 0 010 0 555 0.629 0.207 0.434 85.8 86 2 5 -0.039 -0 029 0 046 0 027 0 583 0.586 0.043 0.212 86.2 85.8 6 -0 034 -0.035 0 037 0 025 0 538 0.502 0.197 0 123 97. 7 105 9 7 0.010 -0 014 0 010 0 008 0 653 0 648 0 536 0.414 83.3 92 .4 8 0 028 0 037 0 033 0 035 0 619 0.635 0.426 0.256 80.7 87.7 9 0 015 0 020 0 028 0 020 0.598 0 622 0.173 0 295 105.2 95.7 10 0.004 0.011 0 012 0 014 0 610 0 599 0 165 0.233 80 9 73.4 Results Average I 0.0141 0 .0041 0 .0341 0 .0181 0 .6011 0.6021 0 .2341 0.3201 91.0 91. 1 Std Dev J 0 .0321 0 .0241 0 .0171 0 .0091 0 .0351 0 .0431 0 .1411 0 .1121 8 8 8 7 Skewness I -0 .4641 0 .9261 -0 .0921 0 .831 -0 .5651 -1.4681 1.3321 -0.4381 0.348 -0.47 Comparison p.values Parametric : T-Test 0.162 0.021 0.986 0.112 0 958 Non-Parametric : 0.333 0.022 0.646 0.126 0 878 Wilcoxon Table J.2. (Cont.) Elliptical Path Task Results from Subjects with MS. Seating System Comparison. Angle Deviat ion (") Knee Angle (0 ) Subject Dominant Leg Non-Dominant Leg Wheelchai SCXlOier Wheelchai SCXlOier Wheelchai SCXlOier 1 75. 0 85 0 10 9 21.5 -0.8 -37 2 2 96 2 92.5 3.1 -1.0 10.4 13.7 3 96 1 95 0 -28.0 -19 3 -4 1 -3 4 4 67 3 86 6 3 9 -15 1 10.4 -27.2 5 50 7 56 0 16 3 6 6 1.6 -4.4 6 78 7 96 1 -12.8 8.9 11.8 13.8 7 82 2 88 0 -3.3 -7.5 13 7 1.3 8 65 3 103 1 -7.5 -21. 9 8.7 5.1 9 66. 4 94 3 6.2 4.2 -2.0 4.4 10 68 6 92 1 10 6 -7 2 7 9 -31.4 Results Average I 74.71 88.91 -2.21 -9.21 5.81 -6.5 Std Dev _l_ 14 .21 12.71_ 13.01 10 31 6 .41 18.7 Skewness I 0.2211 2 .1691 -0 .6041 0 .2111 -0 .4281 -0 703 Comparison p.values Parametric: T-Test 0.008 0 039 0 063 Non-Parametric : 0.013 0.037 0.114 Wilcoxon 163

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J.1.3 Can Stacking Task Table J.3. Can Stacking Results from Subjects with MS. Seating System Comparison .. Can Stacking Completion Time (s) Subject Sealing System Comparison Wheelchair Scooter 1 18.45 22.47 2 7.16 6 9 3 4 99 5.47 4 6 99 5 27 5 5 .61 4 n 6 5 36 5.33 7 9 87 9.57 8 4.1 7 7 74 9 3 n 3 93 10 8.71 9.73 Results Average I 7.511 8.12 Std Dev I 4 .311 5.42 Skewness I 2 .093_1 2 437 Comparison _I)-Values Parametric: T-Test 0 .321 Non-Parametric: 0 575 Wilcoxon 164

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J.2 Results from the Comparison Group J.2.1 Lateral and Forward Reaching Task Table J.4 Lateral and Forward Reaching Task Results from the Comparison Group Seating System Comparison. Average Trunk Flexion/Extension Angle Average Lateral Trunk Flexion/EXtension Maxi mum Trunk Flexion/Extension from Vert i cal (0 ) An le(") Subject Wheelcha i r Scooter Wheelchair Scooter Wheelchair Scooter Ini tial Final Ini tial Fina l Initia l Final Initial Final Initial Fina l Initia l Fina l Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach 1 5 8 13.6 9 3 5 3 11.4 11. 1 17.5 14.4 39.3 47.9 46.3 39 0 2 17 1 13 4 12.5 15.3 11.8 11. 8 9.6 11.7 59.4 56.5 61. 0 56 5 3 -5 9 2 0 10. 6 7 1 21. 8 19.1 7 3 14 2 50.5 49 8 50. 5 46 7 4 4.2 2.3 6 7 8 7 15 4 t7. 4 12. 4 13 4 44 8 43.1 50.4 46 6 5 11.4 14.4 17 8 20. 0 13. 5 10 0 10. 9 8.t 54 8 47 5 54 5 46 6 6 10 6 11.5 6.9 10.6 13.3 11. 0 14.9 12.4 45. 2 47.4 39. 0 44 1 7 4.3 6.4 4.4 4.3 21.4 24.4 20.3 22.7 41.2 45.4 42.5 38 6 8 -5. 9 .8 -5 9 -7.8 14.8 13 9 16.9 16.1 18 1 9.9 18.8 12 9 9 0 9 1.8 5 3 6 0 1 4 1 0 .8 -3 1 43. 4 42 4 43 2 41. 4 10 0 9 4 6 -5 1 -2. 1 1. 0 12 2 1 3 9 11. 1 43. 4 48.1 34 2 39. 1 Results Average 4.3 6.0 6 2 6.7 12.6 13 2 12.2 12 1 44 0 43.8 44 1 41.1 StdDev 7 3 7.5 7.3 7.9 7.01 6.31 6.31 6.6 11.11 12.51 11. 8 11. 3 Skewness 0 152 ..0.821 ..0. 486 ..0. 204 ..0.5891 -1.1511 1 142 -1.26TI_ -2.5731 ..0.904 -1.781 Comparison p-yalues Initial to Final Wheelchair to Initial to Final Wheelchair to Initial to Final Wheelchair to Reach Scooter Reach Scooter Reach Scooter Wheel char Scooter Initial Final !Vheelc:hai Scoote r Initial Final 1'1/heelcha Scooter Initial Final Parametric: T -Test 0 230 0 584 0 382 0.672 0 664 0 934 0.861 0.252 0 908 0.073 0 974 0.093 Non-Parametric : 0.290 0 560 0 510 0.721 0 720 0.510 0.580 0 240 0.959 0.139 0 678 0.110 Wilcoxon Table J.4. (Cont.) Lateral and Forward Reaching Task Results from the Comparison Group. Seating System Comparison. Maximum Lateral Trunk Path Length (m) Lateral Reaching Ratio Flex i on/Extension Angle(") Subject Wheelchair Scooter Wheelchair Scooter Wheelchair Scooter Initial Final Initial Final :nitial F i nal Initial Final Ini tial Final Initial Final Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach 1 30 8 36.9 47 3 41. 1 17.2 1 7. 0 15.4 16 6 1 16 1.18 1 .21 1.27 2 37 1 40.4 39.8 36.9 15.8 15 0 15.4 15 0 1 17 1.24 2 18 1.24 3 47 9 46.9 37 5 42 9 19. 9 18 1 17.6 18 2 1 33 1 34 1 52 1.48 4 36.6 44.0 42.8 40 5 17 0 17 .4 16 9 16 1 1 .25 1 16 1 .38 1.28 5 42 8 41. 0 39. 7 32. 8 18 4 17 7 18 0 17.4 1 36 t .29 t .29 t.38 6 46 9 44 0 41. 7 38 4 18.4 20. 5 17 5 t6.9 1 .38 1.38 t.33 1.40 7 49.5 53.9 5t. 8 45.4 17.1 17.0 16.8 16.2 1 18 1.18 1 .27 1.20 8 32 0 32.3 40.4 38 7 14.3 14 7 15. 2 14.2 1 09 1.09 1 19 1.14 9 32 5 27.2 2 1 5 20. 3 18.8 18 3 18.1 18 0 1 .32 1 .31 1 .30 1 33 10 32 1 40 3 43. 0 37 1 18. 8 18 5 19. 0 19 4 1 32 1 .31 1.42 1 .03 Results Average 38.8 40.7 40. 5 37.2 17.6 17.4 17.0 16 8 1.25 1.25 1 .41 1.28 Std Dev 7 3 7.5 7 9 6 9 1.6 1 7 1 3 1 5 0 .10 0.09 0 29 0 13 Skewness 0 407 ..0.161 -1. 476 -1. 696 ..0.72TI_ ..0. 138 ..0.238 ..0. 056 ..0. 348 ..0.281 2.527 ..0. 369 Comparison p-yalues Initial to Final Wheelchair to Initial to Final Wheelcha i r to Initial to Final Wheelchair to Reach Scooter Reach Scooter Reach Scooter Wheelcha Scooter Initial Final 1'1/heelchai Scooter Initial Final 1'1/heelcha Scooter Initial Final Parametric: T Test 0 237 0 018 0 564 0 038 0 590 0 417 0 070 0 1 3 9 0 789 0 218 0 149 0.486 Non-Parametric : 0.241 0 028 0 646 0.092 0.290 0 290 0.060 0 090 0.833 0.308 0 037 0.109 Wilcoxon 165

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Table J.4. (Cont.) Lateral and Forward Reaching Task Results from the Comparison Group. Seating System Comparison. Forward Reaching Rallo Maximum Frontal COP (m) Frontal COP RMS (m) Subject Wheelchair Scooter Wheelcha i r Scooter Wheelchair Scooter Initial Final Initial Final In i tial Final In i tial Fina l Initial Fina l l nltl al Final Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach 1 1.69 1.69 1 .63 1.68 0.046 0.047 0.065 0 061 0.008 0.009 0.005 0.000 2 1.73 1.72 1.66 1.72 0 115 0 110 0.094 0 084 0.018 0.013 0 027 0.016 3 2.05 2.03 1 78 1.84 0 123 0.121 0.120 0 085 0.030 0.033 0.052 0.009 4 1 .88 1.78 1 .72 1.69 0.109 0 130 0.078 0 080 0 005 0.017 0 004 0 004 5 1.66 1 40 1 .70 1 .55 0 .076 0.048 0 119 0 102 0.012 0.009 0 .053 0 039 6 1.72 1 78 1.65 1.69 0 056 0.054 0.057 0 047 0.018 0.012 0 008 0.010 7 1.71 1.82 1 .80 1.76 0 085 0.100 0.055 0 070 -0.009 -0.007 -0 029 0.003 8 1.34 1.37 1 .47 1.55 0 041 0.051 0.066 0 041 0.000 -0.001 0 015 -0.010 9 1.65 1 63 1 67 1 .69 0.107 0 079 0.070 0 082 0.015 -0.001 0 003 -0.003 10 1 65 1 87 1 .88 1 88 0 .085 0 065 0.073 0 .075 0.012 0 006 0 005 -0.003 Resulls Average I 1.711 1.711 1.691 1.701 0 .0841 0.0831_ 0.080 0.073 0.011 0.009_1 0 014 0.007 Sid Dev 0.18 0.20 0 .111 0.111 0 .0291 0.0321 0.024 0 018 0 .0111 0.0111 o o25L 0.014 Ske'Mless -0.056 -0. 505 -0.676 0 098 -0.249 0.2011 0 992 -0 .4651 -0.1621 0.8121 0.2791 1 610 Comparison p-values Initial to Final Wheelchair to In i tial to Final Wheelchair to Initial to Final Wheelchair to Reach Scooter Reach Scooter Reach Scooter Wheelchai Scooter Initial Final 1\{l!eelchaJ Scooter Initial F i nal !Nheelch ai Scooter lniUal Final Parametric: T-Test 0 931 0.658 0.799 0 897 0 740 0 .190 0 603 0 313 0 431 0.226 0 568 0 603 Noll-Parametric : 0.859 0 284 0.799 0.722 0.678 0.241 0.508 0 241 0.330 0.110 0.801 0.440 Wilcoxon Table J.4. (Cont.) Lateral and Forward Reaching Task Results from the Comparison Group. Seating System Comparison. Avela!Je.of Maxim u m Frontal Maximum Lateral COP (m) Lateral COP RMS (m) Subject Scooter Sel oter Scooter ::nal I.OX. 0.1 0 .04< 0 16 : 0.189 1 103 0.04G 0.03 0 .157 1 125 0 .0& -0. 024 -( 0.!)19 02 0.' 0.025 0 099 0.10 0.118 1 108 0 .01" 0 005 ( 020 0.020 030 ).0!6 0.026 0.029 0.131 0.111 0.093 .10C o.03 0.041 ( 013 0.021 10 0.031 _0.034 0.033 1.031 0 132 0 14' 1.100 1 106 0.01" 0.056 031 0.012 I Results !Average I 0.0321 0.031 1 .0301 1 .0311 0 .1391 0.1261 1 .1181 0 .1171 0.0301 0 025 1 1 .0071 0 020 I Sid Oev 0.0121 0 .0131 1.0051 1.0081 0.0231 0 .0401 1.0241 0121 0.0401 0.0341 0491 025 0.2521 0 .4821 1.467 .0221 0 .3031 -1.0471 1.5191 -0 .3391 -2.0931 -1.0581 -1.3951 -1.575 Comparison p-values to Saoterto Scooter Scooter Initial _final Mleetcna Scooter Initial Final VV!leeiCila Scooter Initial Final Parametric: T-Tesl 0.205 0 430 0.472 0.965 0 321 0.917 0.099 o :540 0.648 0 359 0 .211 0.486 0 230 0 453 0 720 0 380 0 475 0.799 0 126 0 374 0 682 0 440 0 .330 0 .310 166

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Table J.4. (Cont.) Lateral and Forward Reaching Task Results from the Comparison Group. Seating System Comparison Average _of Lateral to Mid GT Height from Wrist to Shoulder (m) Subject Sec oter Sccoter Scc-oter ::nm : 1inal ::nm :!nm 0 91 J29 0.2: 0.221 .03 JJ9 0.186 0.172 9 1.040 m D. 0 229 0.257 10 0 048 0 )42 0. 0 rae _0. 248 0. !21 ().266 Results IAveral!ll 1 .0471 0 .0461 0.0411 _().(]431 0.6541 _0.6371 0.2181 0 .2341 0.2201 0.232 IStd Dev I 1.011 0 .0131 0.0061 _().()()81 _[).0591 _0.0471 _D.032l 0.0321 0.0301 0.039 1 __!l.!II1l 0 .7151 0.5931 -0 .11_71 1.0461 0 .9171 0.3191 -0.11ID_ -0.255 p-values to to Scooter u Scooter Scooter Scooter Initial Final scooter lniUal Finm scooter Initial Final Parametric: T-Test 0.750 0.412 0 192 0 605 0 935 0.189 0 656 0 162 0.138 0.203 0 766 0 884 Wilcoxon 0 864 0.480 0.901 0 810 0 893 0.243 0.702 0 228 0 142 0.234 0.743 0.903 Table J.4. (Cont.) Lateral and Forward Reaching Task Results from the Comparison Group. Seating System Comparison. Trunk-Leg Angie (") Knee Angle (") Sub jed Wheelcha i r Scooler Wheelchair Scooter Initial Final Initial Final I nitial Final Initial Final Reach Reach Reach Reach Reach Reach Reach Reach 1 82.6 86.8 78. 7 88.8 82. 6 88. 8 85. 1 88. 8 2 99.0 94 0 104 2 99.0 101 4 96.3 96.6 91 4 3 92.1 99. 5 85.3 95.0 114.5 113 5 95.4 93.5 4 82.1 75.5 89. 2 85.0 72.4 66. 6 83.0 74.9 5 79.4 81.0 n.8 84.2 77.3 78 8 80.3 81.9 6 84.9 91. 7 78. 6 91.3 84. 9 91. 7 79. 4 91.3 7 89. 0 97 9 80. 9 85.6 89. 0 97 9 84.7 95. 6 8 82. 2 75.8 92 1 83. 0 82. 2 65. 8 75. 4 83.0 9 79.4 74.7 84. 5 83.8 79.4 74.7 77.9 83.8 10 74.2 78.7 70. 0 84.3 74.2 78 7 81.4 84.3 Results Ave rage I 84. 5 85. 6 84 1 88. 0 85.8 85. 1 83. 9 86. 9 StdDev 7 1 9.6 9 4 5.4 13.0 15. 1 7 0 6 4 Skewness 0.832 0.273 0 868 1.1661 1.4181 0 .4681 1.024 -0. 415 Comparison p-values in i tial to Finm Wheelchair to Initial to Final Wheelchair to Reach Scooter Reach Scooter Whee!chai Scooter In i tial Final VVheelchai Scooter Initial Final Parametric: T-Test 0.601 0.170 0.868 0.279 0.766 0.187 0.491 0 .581 NOD-Parametric : 0 596 0 192 0 893 0.312 0 803 0.176 0.541 0 465 Wilcoxon 167

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J.2.2 Elliptical Path Task Table J.5. Elliptical Path Task Results from the Comparison Group. Seating System Comparison. Average Trunk Average Lateral Flexion/Extension Trunk Path Length per Frontal COP Frontal COP RMS Subject Angle from Vertical Flexion/Extension Cycle (m) Displacement (m) (m) () Angle{0 ) Wheelchai Scooter Wheelchai Scooter Wheelchai Scooter Wheelchai Scooter Wheelchai Scooter 1 14.7 12.9 15.4 16.6 2.17 2 14 0 .02 0 .01 0.020 0.024 2 16.7 15.6 16.0 24.6 1.92 1 92 0 00 0.02 0.019 0.018 3 12.0 15.1 8.5 8.9 2 .11 2.28 0 03 0 00 0 046 0.051 4 14 7 12. 4 17.3 10.5 2 .41 2 .07 0 .04 0 .01 0 060 0.020 5 17.8 27.8 12.1 12.4 2.06 1 83 0 .01 0 .04 0.015 0.018 6 17.8 13.3 12.1 16.4 2 06 2.14 0 02 0.01 0.020 0.013 7 9.8 11.2 22.1 8.1 1.67 2 04 -0.01 0.01 0.018 0.011 8 11. 0 11.3 11.3 9.3 1.58 1 .53 0 .01 0.03 0 023 0 023 9 13.6 11.8 13.2 11.4 2 17 2 .00 0 .01 -0.01 0 023 0.017 10 8.2 8.5 14.4 11.5 1.67 1.52 -0.01 -0 .01 0.007 0.004 Results AveraQe I 13.61 14.01 14.21 13.01 1.981 1.951 0 .0131 0.0121 0.0251 0.020 Sid Dev I 3.31 5.21 3.71 5.01 0.271 0 .261 0.0141 0.0141 0.0161 0.012 Skewness I -0.2151 2.3031 0.7461 1.5581 -0.2311 -0 837 0 .1791 0.4021 1.5571 1.835 Comparison !>-Values Parametric : T-Test 0.775 0.526 0.617 0.929 0 .259 Non-Parametric: 0.801 0.582 0.602 0.720 0 240 Wilcoxon Table J.5. (Cont.) Elliptical Path Task Results from the Comparison Group. Seating System Comparison. Lateral COP Lateral COP RMS Distance from Mid Height from Wrist to Acromium to Mid GT Trunk-Leg Angle (0 ) Subject Displacement (m) (m) (m) Shoulder (m) 1 0.048 0.038 0 055 0 031 0 662 0 695 0 218 0.229 105.0 110 3 2 0.067 0.055 0 076 0.116 0 654 0 622 0 .204 0 194 106 8 101.5 3 0.031 0.033 0.038 0.038 0 .760 0 .821 0 .. 241 0.260 111-S 120.2 4 0.074 0.033 0.083 0 019 0.638 0 587 0. 238 0.219 98.6 90.7 5 0.068 0.061 _Q._QI3 0.654 0 237 0.241 94.8 96.7 6 0.050 0.024 0.070 0.032 0 .576 0.622 0 211 0.22 104 1 112.9 7 0.050 0.017 0.065 0 024 0.686 0.754 0 563 0 .61 87 96.2 8 0.02C _Q.Q_34 _Q.026 O."ill_ 1.604 1.511 98. 78.8 9 0.036 0.033 0.043 0 017 0.700 0 658 0 .202 0.19 123. 115.7 10 0.012 0 .012 0.017 0 .010 0 738 0.782 0 .200 0.212 97. 103.8 Results I Average I 0.0461 0.0341 0.0551 0.0321 0 .6811 0.6801 0 2831 0.2811 102 .81 102.71 IStd Dev 0._()_211 _Q.Q1_5L _M23I @311 0. 0.1371 0 .1351 9.81 12.61 I -0. 2451 _M_72l :Q.449l -O..JII 1 .7@l 2.187l 0.689l 'p.values Parametric : T-Test 0.059 0.037 0.961 0.852 0.967 Wilcoxon .. 0.066 0.051 0.857 0.659 0.989 168

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Table J.5. (Cont.) Elliptical Path Task Results from the Comparison Group Seating System Comparison. Angle Deviation (") Knee Angle (") Subject Dominant Leg Non-Dominant Leg Wheelchai Scooter Wheelchai Scooter Wheelchai Scooter 1 82.5 89 2 2 2 3.4 2.9 2.6 2 101. 0 87 9 2 1 3 0 2 6 2.5 3 115 3 102 6 2.5 3.4 2.8 2.9 4 n.4 79.7 2.2 2.9 2.3 2.6 5 55 7 57 1 2 6 3.1 2.4 3.0 6 84 3 103 8 2.8 3.2 2.5 3 2 7 86 3 96.8 3.0 3.2 2.4 3.4 8 79. 7 82 5 2.2 2.3 1.7 2.6 9 77. 7 88 6 2 7 2.7 1.9 3 1 10 83 0 97. 6 3 2 3 0 2.0 3.6 Results Average I 84 .31 88 .61 2 .51 3.01 2 .41 2.9 Std Dev I 15 .61 13 .71 0.41 0.31 0.41 0.4 Skewness I 0.3891 -1.3321 0.4251 -0 .9501 -0 .3191 0.382 COmparison p-values Parametric: TTest 0.237 0.010 0.013 Non-Parametric: 0 325 0.015 0 016 Wilcoxon J.2.3 Can Stacking Task Table J.6. Can Stacking Task Results from the Comparison Group. Seating System Comparison. Can Stacking Completion Time (s) Subject Seating System Comparison Wheelchair Scooter 1 4 .09 4.08 2 3 39 3 09 3 4 23 4.37 4 2 .85 3.33 5 3.42 3.43 6 3.43 3 45 7 3 82 3.14 8 3 53 3.73 9 3 76 3 6 10 3.48 4 13 Results Average I 3 .601 3.64 Std Dev I 0 .391 0.44 Skewness -0.140 0.473 Com.Jl.arison !!-_Values Parametric: T0 776 Test Non-Parametric: 0.721 Wilcoxon 169

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Appendix K: Individual Data for the Order Performed Comparison K.l Results from Subjects with MS K.l.l Lateral and Forward Reaching Task Table K.l. Lateral and Forward Reaching Task Results from Subjects with MS. Order Performed Comparison. Average Trunk Flexion/Extension Angle Average lateral Trunk Flexion/Extension Maximum Trunk Flexion/Extension from Vertical ("} An let"} An ler> Subject First Seating Second Sealing First Sealing Second Seating First Seating Second Seating _yslem Tested Svstem Tested Tested Svstem Tested Svstem Tested System Tested Initial Final Initial Final Initial Final Initial Final Initial Final Initial Final Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach 1 -12.3 -0 5 1 0 -0. 5 5 9 1 7 3 0 7 2 -5 6 8 5 5.0 4 0 2 3 1 1.1 1.9 -1.8 16.9 16.5 18.1 14 6 31. 0 29 2 28 4 18.1 3 -0.7 1.1 0.2 -0.6 14.8 13 0 13.3 12.4 32 8 31.1 31.3 32 0 4 -4.4 -5.0 0 0 -2.1 10.1 8 5 9.2 8 8 12.9 10.2 14.1 9 6 5 3.7 6.4 3 7 5 3 10.0 15 4 10.5 14 6 10.1 24.4 10.1 20 7 6 18 3 22 4 26 6 23 4 5 8 6 3 11. 2 10 3 45 8 47.8 51.3 47.9 7 -4. 7 -19.8 -27 0 -27.2 5.0 15.1 3.3 4 5 5 5 13.8 21.0 20 3 8 -5. 4 -6.3 -7 6 -9.3 8.6 6 3 7 5 8 8 26 0 17.7 12 6 8 2 9 20.8 15.1 15 8 19.2 16.5 14 5 11.0 10 9 40.0 43.7 42 8 43.6 10 12 3 9.6 9 4 11.8 5.4 3 3 8.1 3 9 28. 6 21.5 19.0 23 6 Results Average l 3 .11 2 .41 1.81 9 .91 10.11 9.51 9.61 21.61 24.78 23.571 22 79 Sid Dev I 10.91 11.81 14 .11 14.51 4 .71 5.51 4 .51 3 .71 17.93 13.36 14.661 14.61 Skewness I 0.5051 -0.1361 -0.4151 -0.440 0 555 -0.290 0.254 -0 155 0 555 -0.290 02541 -0.155 Comparison p-values Initial to Final First to Second I nitial to Final F i rst to Second Initial to Final F irst to Second Reach Sealif!ll_y_stem Reach Seating Sys\J!m Reach Seating System First Second F irst Second First Second Seating Sealing Initial Final Seating Seating Initial Final Seating Sealing Initial Final System System Reach Reach System System Reach Reach System System Reach Reach Tested Tested Tested Tested Tested Tested Parametric: T-Test 0.782 0 629 0 772 0.585 0 918 0 935 0 669 0 749 0 322 0 674 0 588 0 266 Non-Parametric: 0.799 0.575 0.659 0.635 0 508 0.919 0.508 0 919 0.445 0.610 0 676 0.359 Wilcoxon 170

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Table K.l. (Cont.) Lateral and Forward Reaching Task Results from Subjects with MS. Order Performed Comparison. Maximum lateral Trunk Path Length (m) Lateral Reaching Ratio Flexion/Extension Angle(") Subject First Seating Second Seating First Seating Second Seating First Seating Second Seating System Tested System Tested System Tested System Tested System Tested System Tested Initia l Final Initial F inal Initial Final Initial Final Initial Final lnltial Final Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach 1 16.6 9.8 9 0 13 5 13.6 13 8 12.8 13.1 0 96 0.93 1 00 0.95 2 37 0 35.9 35. 0 31.3 18.9 19 3 18.9 19 5 1 18 1.11 1.10 1.02 3 38 9 35.3 32 3 29 6 16 3 18.4 15.7 16.1 1 20 1.14 1.14 1.05 4 21. 1 20. 9 19 6 18 0 17.5 15 7 15 2 17 1 0 78 0.43 0.48 0 74 5 20 9 28 4 21. 3 29 9 14 3 15.9 14 5 14 9 0 67 0.75 0 .67 0 72 6 34 5 35.5 36 3 34.9 16.5 14 8 15 3 15.3 0 98 0.90 0 95 0 89 7 9.1 21.8 10.8 12.9 12.1 11. 8 11.8 11.6 0 80 0.74 0.88 0 86 8 34.6 29.3 32 6 21.3 17.3 16.4 16 0 15.1 1 30 1.21 1.10 1.10 9 36 4 33.4 36.4 35 8 15.5 16 6 18.2 18.1 1 20 1.16 1.16 1 20 10 18 1 16.6 19 8 15.1 19.1 16.4 13 8 14 2 1 12 0 99 0.86 0 88 Results Avera!le 26.71 26.71 25 .31 24.24 16.1 15 9 15.2 15.5 1.01 0.94 0.93 0 94 Sid Dev 10.63 9.03 10.53 9.03 2.3 2 1 2 2 2.3 0.21 0.24 0 .22 0.15 Skewness 0.555 -0.290 0 254 -0 155 -0.400 -0.357 0 256 0 113 -0 398 -0.951 -1. 050 0 120 Comparison p-Y&Iues Initial to Final First to Second Initial to Final First to Second to Final Wheelchair to Reach Seating System Reach Seating System Reach Scooter First Second First Second Seating Seating Initial Final Seating Seating Initial Final First Seating Second Seating System System Reach Reach System System Reach Reach System Tested System Tested Tested Tested Tested Tested Parametric: T-Test 1.000 0.547 0.217 0.105 0 675 0.219 0.186 0 367 0.036 0.868 0 .061 0.919 Non-Parametric: 0.508 0 445 0 260 0 126 0 .721 0 173 0.110 0.445 0 032 0.593 0 076 0.799 Wilcoxon Table K.l. (Cont.) Lateral and Forward Reaching Task Results from Subjects with MS. Order Performed Comparison. Forwanl Reaching Ratio Frontal COP RMS (m) Average ol Maximum COP Frontal Displacement (m) Subject First Seating Second Seating First Seating Second Seating First Seating Second Seating System Tested System Tested System Tested System Tested System Tested System Tested Init ial Final Ini t ial Final Initial F inal Initial F inal Initial Final Initial Final Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach 1 1 0 1 0 1 0 1 0 0 004 0 003 0.003 0 005 0 007 0 009 0 012 0 018 2 1 5 1.5 1 5 1.4 0.018 0 026 0.020 0 019 0 .051 0.072 0 036 0.048 3 1 6 1.5 1 6 1.5 0.021 0 017 0.035 0.019 0 068 0.058 0 104 0.055 4 1 3 1.2 1 2 1 3 0.007 0 006 0.010 0 005 0.024 0.014 0 007 0 004 5 0.7 0.8 0 7 0 9 0 015 0 007 0 005 0.009 0 .031 0 017 0 009 0 022 6 1 0 0.9 0 9 0 9 0 024 0 009 0.027 0 029 0 083 0 097 0 079 0 090 7 1.0 0 9 1 0 0.9 0 007 0 006 0.006 0 006 0 008 0.019 0 026 0.022 8 1 6 1.5 1 3 1.3 0.018 0.016 0.006 0 007 0.071 0.053 0 024 0.006 9 1 5 1.5 1 6 1.6 0 .021 0 025 0.022 0.024 0.050 0.060 0 .061 0 076 10 1 2 1.1 1.2 1.1 0.004 0 005 0.004 0.006 0 009 0.011 0 005 0 008 Results Average 1 24 1.20 1 18 1 18 0.014 0 012 0 014 0 013 0 040 0.041 0 036 0 035 Std Dev 0 .31 0.30 0 30 0.27 0.008 0 008 0.011 0.009 0.028 0.031 0 034 0.031 Skewness -0.390 0.026 -0 100 0.186 -0 220 0 .601 0.834 0.782 0 158 0.540 1 088 0 798 Comparison p-Yalues Ini tial to Final Whee l chair to Initia l to Final First to Second Ini tial to F inal F irst to Second Reach Scooter Reach Seating System Reach Seating System First Second First Second First Second Seating Seating Initial Final Seating seaung Initial Final Seating Seating Init ial Final System System Reach Reach System System Reach Reach System System Reach Reach Tested Tested Tested Tested Tested Tested Parametric: TTest 0 .151 0 916 0.089 0 434 0 358 0 658 0 900 0 752 0.847 0.827 0 614 0 318 Non-Parametric : 0.059 0 739 0.257 1.000 0 304 0.632 0.677 0.676 0.759 0.683 0.646 0.443 Wilcoxon 171

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Table K.l. (Cont.) Lateral and Forward Reaching Task Results from Subjects with MS. Order Performed Comparison. (m) Average_"' Lateral Distance from to Mid GT l07 ,007 IXl' 0.004 IJl 0.01 0 022 J.Q: 0. 0.51: f!J7 0.: _-QJlQS 0 009 0.6C 578 1.57E 1 03l 0 039 0 080 1 .00 0.1' 0.116 0 .6C 594 1 .561 0 .02:! 1 .021 1 032 0 056 05 O .OE 0.059 O.S!ll 581 1 566 00 1 .00 1.01 0.015 034 02 o.oc 0.01: 0.58' .550 0 .:611 0.552 Results IAveraae 0 .0181 0 .01' 1 .0211 0 .0221 0 .0501 04(l 1.0501 0 .0521 1.5821 1 .5771 ) .5691 1 .565 IStdDev 1 .0091 1 .0101 1.0141 0 .0131 0331 0261 0 .0391 0.037 0.0351 1 .0401 0 .0341 1.041 I Skewness 1 .6661 1 .5361 1.3961 .0.2301 .0 0531 1 .5271 1 .4281 .0.9191 1 ,0101 1.305 s:Srr:g Initial Final s:!':g Initial Final Initial Final System System Reach Reach System System Reach Reach System System Tested Tastlid Tested Tasted Tested Tested Reach Reach Parametric: T-Tast 0.657 0 578 0.431 0.064 0 170 0 .834 0.934 0 190 0 .461 0.432 0.043 0.046 0 260 1 000 0.476 0 050 0 153 0 678 0.959 0.173 0 285 0 264 0 .051 0.047 Table K.l. Lateral and Forward Reaching Task Results from Subjects with MS. Order Performed Comparison. Height from Wrist to Shoulder (m) Trunk Leg Angle (0 ) Knee Angle (") Subject First Seating Second Seating First Seating Second Seating First Seating Second Seating System Tested System Tasted System Tested System Tested System Tasted Svstem Tested Initial Final Initial Final Final Init ial Final Initial F inal Initial Final Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach 1 0 102 0.102 0.107 0.137 69.5 83.8 66 0 66.0 75.1 71.0 90.8 88.3 2 0 094 0 .100 0.083 0.083 98.1 97.2 95 5 94 5 93 5 93 9 96 6 98 3 3 0 .161 0 .138 0 118 0 160 85 2 85.1 64 1 82 3 95 4 95 8 97. 6 96 4 4 0 193 0 205 0 194 0 213 81. 6 80 3 81.8 78 3 57.8 68 1 85 6 87 2 5 0 233 0 253 0.233 0.249 78.5 76 7 70 4 70 5 58.3 64 4 52. 1 47.5 6 0.252 0 229 0.241 0.217 89.0 89 6 102 7 100.0 79.4 77.7 94. 2 95.3 7 .0.116 0 .014 0 002 .0.002 66. 7 64 8 79 2 78. 3 104.5 92 1 64 7 83.2 8 0 139 0 .137 0 117 0 129 82.2 82.0 66. 1 82.7 67.4 68 2 105.4 104 3 9 0 200 0 204 0.208 0.209 92.5 92.3 91. 6 94 4 96 6 94 3 67 9 62.7 10 0 194 0 192 0.200 0.197 80.7 78 3 n 5 70 2 61.4 75 6 91. 4 88.5 Results Average 0.146 0 .158 0 .151 0.159 64. 4 85 0 85 5 83. 7 78 9 80 1 86 6 85 2 StdDev 0 100 0 074 o .on 0.075 7 9 6 4 9 3 10 1 17.6 12 6 15. 7 17.4 Skewness I -1.868 .0. 569 .0.615 -1.100 .0. 108 0.679 0.358 0.228 0 116 0 203 -1.3n -1.401 Comparison p-values Initial to Final First to Second Initial to Final First to Second lntlial to F inal First to Second Reach Seating System Reach Seating System Reach Seatin> System F irst Second First Second F irst Second Seating Seating Initial Final Seating Seating Initial Final Seating Seating Initial Final System System Reach Reach System System Reach Reach System System Reach Reach Tasted Tested Tested Tested Tested Tested Parametric: T-Tast 0 393 0.210 0.711 0 886 0 702 0 073 0 666 0.481 0 630 0 086 0 .292 0.442 Non-Parametric: o sn 0 214 0.859 0 838 0.169 0 006 0.878 0.333 0.721 0 114 0.285 0.285 Wilcoxon 172

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Table K.l. (Cont.) Lateral and Forward Reaching Task Results from Subjects with MS. Order Performed Comparison. Dominant L.eg Non-Dominant l..eg_ Subject First Seating Seeonct Seating First Seatlng Seeond Seatlng System Tested System Testecl System Tested System Tested Initial Final Initial F inal lnillal Final lnHial F inal Reach Reach Reach Reach Reach Reach Reach Reach 1 -11.0 4 -3.5 12 7 2 8 -2.5 -3.0 ..0. 4 2 3.3 3 2 -0 7 -3. 1 12 2 13 5 8 9 6 8 3 -18 1 -21. 8 -15 0 9 3 4 0 4 -4.9 -3 1 4 -0.2 0 8 -7 3 -9 2 11. 3 11. 4 17 7 23 8 5 8 0 5 0 5 2 7 4 -5 1 -0 2 2 1 0 9 6 -12 5 16 1 -7.8 -7.6 8.0 9 4 18 4 17 0 7 2 0 17 1 12.2 -18 6 -4 5 15 8 2 -2 7 8 ..0. 3 -8 3 18 3 -22 4 3 7 5 3 13 3 7 3 9 11. 0 2 0 5 0 1 8 3 4 1 3 7 6 6 9 10 3 8 7 8 3 6 8 9 5 7 9 -13 0 7 Results -2.0 -5 6 -5 1 ..0. 4 4 5 3 1 1 1 -1. 7 S1ct0ev 9 .51 10 6 8 .41 11.91 6 .01 8 .51 11.31 12 6 SkeiM'Iess -0 405 -0 255 -0 182 0 092 -0.425 -1. 089 -0 173 -0 580 Comparison p-values Init i a l to F inal First to Se!:ond I niti a l to Final F irst to Se!:ond Reach Seatlng System Reach Seating System F irst Seeond First Sealnd Seating Seating lnHial Final Seating Seatlng Initial Final System System Reach Reach System System Reach Reach Testecl Tested Tested Tested Parametrlc: T-Test 0 112 0 578 0.196 0 834 0 .351 0.012 0 443 0 354 Non-Parametrlc: 0 093 0 169 0.241 0 575 0.359 0 022 0 760 0 646 WilalXOO 173

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K.l.2 Elliptical Path Task Table K.2. Elliptical Path Task Results from Subjects with MS. Order Performed Comparison. Average Trunk Average Lateral Aexlon/Extenslon Trunk Path Length per Frontal COP Frontal COP RMS Angle from Vertical Flexion/Extension Cyde(m) Displacement (m) (m) Subject l'l Annie(') First Second First Second First Second First Second First Second Seating Seating Sealing ;E: Seating Seating Seating Seating Seating Seating System System System System System System System System System Tested Tested Tested Tested Tested Tested Tested Tested Tested r 6 5 1 1.15 1 24 1.0( 0 009 0 004 -He o.oc o .oo: 0.02E ro 0 o.oTI 0 010 0.025 Q.004 (j]ffij o:oD4 02 o:D15 D.lff1 2 3. 19 7 1 10. ).9 1 0 a.a 3 6 6 2 13 8 1 .26 1 57 29 28. 24 -18.3 "232 2.71 o.of If 11 11. 22. 11.9 2.10 1.88 -0 0' o:o1 lfO'I2 ).005 Results !Average 12.61 12 .91 18 .01 13 .41 1 .651 1 .741 1.0081 0 011 0.0171 0 015 IStdoev 8 .61 8 .61 9 .31 5.21 0 .521 0.581 1.0101 0 .0101 0 .0121 0 .011 I 0.5141 0 .3751 0 .6221 -0.2531 0 .5371 0 .8901 1 .8901 2.8901 1 .3021 0 360 1 p..vaJues Parametric: T-Test 0.898 0 113 0.182 0.543 0 647 .. 0 959 0.114 0.202 0.610 0 445 Table K.2. (Cont.) Elliptical Path Task Results from Subjects with MS. Order Performed Comparison. Subject 8 9 10 Std Dev 1 P-values Parametric: T-Test Wilcoxon Lateral COP Displacement (m) First Sealing System Tested 0 0 0.02! 0.02( 0 .00< Second Seating System Tested ) .000 l .D4t: ) .021! -0 .0051 -1).035 0.01C 0.037 l 01f ) .011 Distance from Mid Letera1 COP RMS A I I M 'd' ,T Height from Wrist to Trunk Leg Angle (') (m) aom 1 "'' Shoulder (m) First Seating System Tested 0 0 Second Seating System Tested 0 .0: 01( 035 )28 014 First Sealing System Tested 0.5311 Second Sealing System Tesled o .sa:; 1: .5!1 First Seating System Tested 0 SeCOnd Seating System Tested First Seating System Tested 8C 95. 8( Second Seating System Tested 87 105 73.4 0.0111 0 .0081 0 027 0 .0251 0 .6021 0 .601 0 .2761 1.2781 90.31 91.8 0 .0301 0 .0281 0 01' 0 .0141 0.0341 0 .0441 0 .1ffi 1.1551 6 .41 10 5 1 .3601 2 .3601 0 .7881 0 .8821 -0.7621 -1.3151 0 .7821 D.ml -0.5281 -0. 113 0.689 0 722 0 982 0.982 0 477 0.799 0.878 0 683 0 959 0.386 174

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Table K.2. (Cont.) Elliptical Path Task Results from Subjects with MS. Order Performed Comparison. Knee Angle (") Dominant Leg Non-Dominant Leg Subject First Second First Second First Second Seating Seating Seating Seating Seating Seating System System System System System System Tested Tested Tested Tested Tested Tested 1 75.0 85.0 -10.9 -21.5 -0.8 -37.2 2 92.5 96 2 -1.0 3.1 13.7 10.4 3 96.1 95 0 -26.0 -19.3 -4.1 -3.4 4 67.3 66.6 3 9 -15 1 10.4 -27 2 5 56 0 50 7 6.6 16. 3 -4 4 1.6 6 78.7 96 1 -12.8 -8. 9 11.8 13.8 7 88.0 82 2 -7.5 -3 3 1.3 13.7 8 65.3 103.1 -7.5 -21. 9 8.7 5.1 9 94.3 66.4 4.2 6 2 4.4 -2.0 10 66.6 92 1 10.6 -7 2 7.9 -31.4 Results Average 78.21 85 4 -4 2 -7 .21 4.9 -5.6 StdOev 14.0 15.9 11.5 12.81 6.6 19 2 Skewness -0.072 -1. 384 -0 795 0 523 -0.239 -0.744 Comparison p.values Parametric: TTest 0.252 0.431 0.122 Non-Parametric: 0;285 0.508 0.203 Wilcoxon K.1.3 Can Stacking Task Table K.3. Can Stacking Results from Subjects with MS. Order Performed Comparison. Can Stacking Completion Time (s) Subject Order Performed Comparison First Seallng Second Seating System Tested System Tesled 1 16.45 22 .47 2 6 9 7 16 3 4 99 5 .47 4 6.99 5. 27 5 4.n 5. 6 1 6 5.36 5. 33 7 9.57 9 87 8 4.17 7.74 9 3.93 3.n 10 8.71 9 73 Results Avera11_e J 7.381 8 24 StdDev I 4.32 5.38 Skewness 2.153 2 412 Comparison p.values Parametric: T-Test 0.149 Non-Parametric: 0.093 Wilcoxon 175

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K.2 Results from the Comparison Group K.2.1 Lateral and Forward Reaching Task Table K.4. Lateral and Forward Reaching Task Results from the Comparison Group. Order Performed Comparison. Average Trunk Flexion/Extension Angle Average Lateral Trunk Flexion/Extension Maximum Trunk Flexion/Extension from Vertical C"l An le("l An!; lie(") Subject First Seating Second Seating First Seating Second Seating First Seating Second Seating System Tested System Tested System Tested System Tested System Tested System Tested Initial Final Initial Final Initial Final Initial Final Initial Final Initial Final Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach 1 5.8 13.6 9 3 5.3 11.4 11.1 17.5 14.4 39.3 47.9 46 3 39 0 2 17.1 13.4 12.5 15 3 11.8 11.8 9.6 11.7 59.4 56 5 61. 0 56 5 3 10.6 7.1 -5.9 2 0 7 3 14.2 21.8 19.1 50.5 46.7 50.5 49 8 4 4.2 2.3 6 7 8.7 15 4 17.4 12.4 13.4 44.8 43.1 50.4 46 6 5 17.8 20.0 11. 4 14.4 10 9 8.1 13.5 10.0 54.5 46.6 54 8 47 5 6 6.9 10.6 10 6 11. 5 14.9 12.4 13.3 11.0 39.0 44.1 45 2 47 4 7 4.3 6.4 4.4 4 3 21. 4 24.4 20.3 22.7 41.2 45.4 42 5 38 6 a -5.9 -7.8 -5 9 -9.8 16 9 16.1 14.8 13.9 18.8 12.9 18.1 9 9 9 0.9 1.8 5 3 6 0 1 4 1 0 -1.8 -3.1 43.4 42.4 43. 2 41. 4 10 -5.1 -2.1 0 9 4.6 13 9 11.1 1.0 12.2 34.2 39.1 43.4 48 1 ResuHs Average 5.6 6 5 4 .91 6 2 12 5 12 8 12.3 12.5 42.5 42.5 45 5 42.5 StdDev 8.0 8.3 6 7 7 2 5 5 6.1 7.6 6.7 11.31 11.3 11.31 12 6 Skowness 0.134 .{). 136 .{).758 1 022 .{). 602 .{).014 .{).820 -1.148_1 .{).657 -2.171 -1. 547 2 134 Comparison p-values Initial to Final First to Second Initial to Final First to Second lnilial to Final First lo Second Reach Seatir111 System Reach Seatin!l System Reach Seati ng System First Second F irst Second F irst Second Seating Seating Initial Final Seating Initial Final Seating Seating Initial Final System System Reach Reach System System Reach Reach System System Reach Reach Tested Tested Tested Tested Tested Tested Parametric : T-Test 0.460 0 273 0.743 0.857 0 .801 0 853 0 905 0.792 0.975 0 049 0.027 0 .991 Nort-Parametric : 0 430 0.320 0.843 0 623 0 453 0 843 0 674 0.563 0 959 0.074 0 028 0.767 Wilcoxon 176

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Table K.4. (Cont.) Lateral and Forward Reaching Task Results from the Comparison Group. Order Performed Comparison. Maximum Lateral Tl\lllk Path Length (m) Lateral Reaching Ratio Flexion/Extension Angle{") Subject First Seating Second Seating F irst Seating Second Seating First Seating Second Seating System Tested System Tested System Tested System Tested System Tested System Tested Initial Final Initial F inal Initial Final Initial F inal Initial Final Initial F inal Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach 1 30.8 36.9 47 3 41 1 172 17 0 15 4 16 6 1 16 1.18 1 .21 1 27 2 37.1 40.4 39. 8 36. 9 15 8 15 0 15.4 15 0 1.17 1.24 2.18 1 24 3 37.5 42.9 47 9 46 9 17 6 18.2 19 9 18 1 1.52 1.48 1.33 1 34 4 36.6 44.0 42 8 40.5 17 0 17.4 16.9 16 1 1.25 1.16 1.38 1 28 5 39.7 32.8 42 8 41. 0 18.0 17.4 18.4 17 7 1 29 1.38 1.36 1 29 6 41.7 38.4 46 9 44 0 17.5 16.9 18.4 20 5 1 .33 1.40 1.36 1 38 7 49 5 53.9 51.8 45 4 17 1 17.0 16 8 16 2 1.18 1.18 1.27 1 20 8 40.4 36.7 32 0 32 3 15.2 14.2 14 3 14 7 1.19 1.14 1.09 1 09 9 32 5 27.2 21. 5 20 3 18.8 18.3 18 1 18.0 1.32 1.31 1.30 1 33 10 43.0 37.1 32 1 40 3 19 0 19.4 18 8 18 5 1.42 1.03 1.32 1 .31 Results AvetaQe 38. 9 39. 0 40. 5 38. 9 17 3 1 7 1 17 3 17 1 1 27 1 .25 1. 38 1 27 StdDev 5.3 7 1 9 3 7 7 1 2 1 5 1 8 1 8 0 12 0 .14 0 29 0.08 Skewness 0 434 0.597 -0 956 -1. 710 -0 464 -0 652 -0 285 0 356 0 897 0.207 2 628 Comparison p-values Initial to Final First to Second Initial to Final First to Second Initial to Final First to Second Reach Seatill!: System Reach Seatin System Reach System F i rst Second First Second F irst Second Seating Seating Initial Final Seating Seating Initial Final Seating Seating Initial Final System System Reach Reach System System Reach Reach System System Reach Reach Tested Tested Tested Tested Tested Tested Parametric: T-Test 0 926 0 238 0 587 0.933 0 .181 0 736 0 840 0 904 0 515 0.287 0 380 0 579 Non-Parametric: 0 838 0 093 0.646 0 878 0 253 0 653 0,824 0 .861 0 8 1 3 0 260 0 646 0 635 Wilcoxon Table K.4. (Cont.) Lateral and Forward Reaching Task Results from the Comparison Group. Order Performed Comparison. Forward Reaching Ratio Maximum Frontal COP (m) Frontal COP RMS (m) Subject First Seating Second Seating First Seating Second Seating First Seating Second Seating System Tested System Tested System Tested Svstem Tested System Tested System Tested Initial Final Initial Final Initial Final Initial Final Initial Final In !Hal F inal Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach 1 1 7 1.7 1 6 1 7 0 046 0 047 0 065 0 .061 0 000 0 003 0 005 0 010 2 1 7 1 7 1.7 1 7 0 1 1 5 0.110 0 094 0 084 0 010 0.019 -0.002 0.010 3 1 8 1 8 2 1 2 0 0 120 0 085 0 123 0 .121 O.Q15 0 011 0.022 0 003 4 1 9 1 8 1 7 1 7 0.109 0 130 0.078 0 080 0 008 0 003 -0 007 -0. 006 5 1 7 1 6 1 7 1 4 0 119 0 102 0 076 0 048 0 009 0 000 0 000 -0 002 6 1 6 1 7 1 7 1 8 0 057 0.047 0 056 0 054 0 015 -0 002 0.015 0 008 7 1 7 1.8 1 8 1 8 0 085 0 100 0 055 0 070 0 .001 0.011 0.015 0 015 8 1.5 1.5 1 3 1.4 0 066 0.041 0.041 0 .051 0 032 0.017 0.010 -0.005 9 1.7 1.6 1 7 1 7 0 107 0.079 '0.070 0 082 0 017 0.005 0.020 0 020 10 1.9 1.9 1.7 1 9 0 073 0.075 0.085 0.085 0.035 0.022 0.027 0 021 ReSI.its Avera e 1.71 1.72 1.69 1 70 0 090 0.082 0.074 0 074 0.014 0.009 0.011 0 008 StdDev 0 .11 0.12 0 17 0 20 0.03 0.03 0 02 0.02 0 012 0 008 0 .011 0 010 Skewness -0 743 -0 168 0 .171 -0 350 -0 356 -0.012 0.830 0 960 0 636 0 328 -0.138 -0 040 Comparison p-values I nitial to F inal First to Second Initial to Final First t o Second Initial to F inal First to Second Reach Seatirn SYstem Reach Seatill!: System Reach Seatin Svstem First Second First Second First Second Seating Seating Initial Final Seating Seating Initial F inal Seating Seating Initial F inal System System Reach Reach System System Reach Reach System System Reach Reach Tested Tested Tested Tested Tested Tested Parametric: T-Test 0 755 0.882 0.696 0 600 0.200 0.858 0.054 0 417 0 110 0.310 0.330 0.697 Non-Parametric: 0 655 0.666 0.607 1 000 0 203 0.906 0.059 0 646 0.165 0.439 0.453 0 763 Wilcoxon 177

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Table K.4. (Cont.) Lateral and Forward Reaching Task Results from the Comparison Group. Order Performed Comparison. Average of Maximum COP Frontal Maximum Lateral COP (m) Lateral COP RMS (m) DiSOlacement !ml. Subjed First Seating Second Seating First Seating Second Seating First Seating Second Seating System Tested System Tested System Tested System Tested System Tested System Tested Initial Final Initial Final Initial Final Initial Final Initial Final Initial Final Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach 1 0.004 0 003 0 003 0.005 0.127 0.140 0.125 0.121 0.001 0 004 0 005 0 008 2 0.018 0 026 0.020 0.019 0 142 0.103 0.154 0.128 0.025 0.002 0.023 0 008 3 0.021 0.017 0.035 0.019 0 123 0.128 0 130 0.128 0.037 0 029 0.019 0.005 4 0.007 0.008 0.010 0.005 0.181 0.180 0.092 0.119 0.012 0.011 0.010 0.000 5 0.015 0.007 0.005 0.009 0 122 0.131 0.128 0.144 ..0.014 0.004 ..0.011 ..0. 014 6 0.024 0.009 0.027 0 029 0.089 0.103 0.167 0.162 ..0. 010 ..0. 014 ..0.012 ..0.019 7 0.007 0 008 0.008 0.008 0.155 0.038 0 157 0.125 ..0.021 ..0.009 0.001 0.003 8 0 018 0.016 0 006 0.007 0.118 0.108 0 099 0.100 0 035 0 022 0.027 0.021 9 0.033 0 039 0 040 0 036 0.131 0 115 0 093 0 100 0.021 0 022 0 .027 0 027 10 0.024 0 023 0 039 0.039 0 100 0 108 0 132 0.147 0.037 0.024 0.012 0 008 Results Average 0 017 0 015 0.019 0 017 0 129 0.115 0 .1281 o.127L 0.012 0.009 0.010 0 004 Std Dev 0.009 0 .011 0.015 0.013 0.03 0.04 0.03 0.02 0.022 0.014 0.015 0.014 Skewness 0.100 1.027 0.393 0.653 0.560 ..0.500 ..0.034 0.157 ..0.281 ..0. 252 ..0.384 ..0.226 Compari50n p-values Initial to Final First to Second Initial to Final First to Second Initial to Final First to Second Reach Seating System Reach System Reach Seating System First Second First Second First Second Seating Seating Initial Final Seating Seating Initial Final Seating Seating Initial Final System System Reach Reach System System Reach Reach System System Reach Reach Tested Tested Tested Tested Tested Tested Parametric: T-Test 0.378 0 .361 0.508 0.495 0.309 0.952 0.934 0 397 0.456 0.028 0.580 0.226 NOI)-Paramebic: 0.483 0 452 0.652 0 552 0.575 0.959 0.838 0 441 0.532 0 060 0.652 0 231 Wilcoxon Table K.4. (Cont.) Lateral and Forward Reaching Task Results from the Comparison Group. Order Performed Comparison. Average of Maximum COP Lateral Distance from Mid Acromium to Mid GT Height from Wrist to Shoulder (m) Displacement (m l (m) Subjec:t First Seating Second Seating First Seating Second Seating First Seating Second Sealing System Tested System Tested System Tested System Tested System Tested System Tested Initial Final Initial Final lnnial Final Initial Final Initial Fina l Initial Final Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach Reach 1 0.007 0 007 0.004 0.004 0 596 0.626 0 642 0 641 0.193 0 218 0.214 0 221 2 0.017 0.014 0.017 0.022 0.621 0.590 0 718 0.621 0.175 0 267 0.185 0.175 3 0.036 0 033 0.031 0.027 0 708 0.765 0 .590 0.707 0.193 0.209 0.179 0.220 4 0.016 0 .011 0.018 0.011 0.653 0.710 0.735 0.617 0.204 0.222 0.229 0 241 5 0.025 0.013 0.012 0.029 0.617 0.605 0.641 0 617 0.261 0.256 0.271 0.251 6 0.015 0 029 0.043 0.037 0.647 0.553 0.594 0.717 0 291 0 269 0.290 0.249 7 0 008 0 008 0.005 0 004 0 606 0.666 0 651 0.651 0.206 0 226 0 187 0.221 8 0.024 0 023 0 039 0 039 0 .591 0.739 0 747 0.606 0 186 0 190 0 172 0 213 9 0 074 0 097 0.102 0 127 0.681 0.640 0 632 0 718 0 244 0 229 0.259 0 257 10 0.084 0 071 0.028 0 033 0 745 0.703 0 .7 98 0 581 0.248 0 234 0.266 0.221 Results Average 0.030 0 031 0.030 0 033 0.646 0.660 0 675 0.648 0.220 0.232 0.225 0.227 StdDev 0.027 0.030 0.029 0.035 0 .051 0.069 0.070 0.050 0.038 0.025 0.044 0.024 Skewness 1.415 1.605 1.976 2.413 0.658 0.045 0 498 0 .5051 0.7011 0 .1381 0.157 ..0.861 Compari500 p-values Initial to Final First to Second Initial to Final First to Second Initial to Final First to Second Reach Seatin' System Reach saauoo System Reach Seating System First Second First Second First Second Seating Seating Initial Final Seating Seating Initial Final Seating Seating Initial Final System System Reach Reach System System Reach Reach System System Reach Reach Tested Tested Tested Tested Tested Tested Parametric: T-Test 0.988 0.288 0.916 0.639 0 570 0.476 0.298 0.692 0.274 0.862 0.343 0.652 Non-Parametric: 1.000 0.243 0.993 0 782 0.632 0.532 0.365 0 .542 0.214 0.740 0.363 0.762 Wilcoxon -178

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Table K.4. (Cont.) Lateral and Forward Reaching Task Results from the Comparison Group. Order Performed Comparison. Trunk Leg Angle (") Knee Angle (") Subject :.eaung :.econa :.eaung :.eaung :.econa :.eaung System Tested System Tested System Tested System Tested lniUal lnJUBI lniUal 1mua1 t-ma1 Reach Reach Reach Reach Reach Reach Reach Reach "" "" '" "" "" "" ...,_ ""' "' >r.I. U ..... '"""" "" lUl. ,...., "" "l. ""' "" ...,_, ""' ll ... "" "" "" 4 IU.l !l:l.ll """" DO '"' '" "" :. lll U (11. 4 "" (6.11 ".. 01 ou "' Ill ..... Ill ;, '" tll.;s 111. 4 tlli. U til. IIU 11:.. 1111.' tj(. 114.( tl'll .t> '" "" "" "" b::l. """" "" ('ll. '" ... 1:14. "" ,,_. '" "" lU_ '" '""" ..... fU.' '" '""" 114. 111. 4 Results lA_verage I 114.'1lJ "" "I "" O<>.UI "" "I oo.u1 ..., "I "" f:>ta uev ll.ul o l:>.ut '" ul "' f:>Kewness U.bU'Ill U .4111L -II-"""' I u '"I I.U::I'tl U .O.t;OI u..:to Comparison p-values IOIUallO t-11131 t-lrstto ::;econa 1mua1 to t-1na1 FIJSt 10 :>econa Reach SeaHng System Reach Seating System t-lfSI ::;econa First :>econa Seating SeaUng Initial Final Seating SeaUng ln!Ual Final System System Reach Reach System System Reach Reach Tested Tested Tested Tested Parametric: TTest 0 590 0 969 0 417 0 853 0 637 0.911 0 .831 0.799 Nor>-t'aramemc: 0.523 0 992 0 530 0.783 0 753 0 939 0 873 0.803 Wilcoxon 179

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K.2.2 Elliptical Path Task Table K.5. Elliptical Path Task Results from the Comparison Group. Order Performed Comparison Average Trunk Average Lateral Flexion/Extension Trun k Path Length per Frontal COP Frontal COP RMS Angle from Vertical Aexlon/Exlenslon Cycle(m) Displacement (m) (m) Subject (") Angle(") First Second First Second First Second First Second First Second Seating Seating Seating Seating Seating Seating Seating Seating Seating Seating System System System System System System System System System Tested Tested Tested Tested Tested Tested Tested Tested Tested 1 14. 12. 1 : 16.1 2 15.6 16. 2 16. 3 12.0 '15. 4 !.4 14. 11 17 3 2.06 1.83 19 0 012 0. : .06 0 013 o .o: 0. 0 O.i 0. 0 10 8.' 1 0. !esults \verage 12.91 14.71 t4.41 12.81 1.941 1.991 0.0181 0.0071 0.0241 0.021 itd Dev 2.81 5.41 5 .41 3.21 0.281 0.261 0.01 0.0081 1.0161 0 012 1.1781 1.6161 1.0131 -0 0191 -0.8721 -0.0821 -0.4761 -0.7431 1.4151 2.041 'D-values Parametric: T-Test 0.134 0 446 0 409 0.040 0.408 Wilcoxon 0 145 0 653 0.542 0 047 0 .678 Table K.5. (Cont.) Elliptical Path Task Results from the Comparison Group. Order Performed Comparison. Lateral COP Lateral COP RMS Distance from Mid He i ght from Wrist to Acromium to Mid GT Trunk. Leg Angle (") Displacement (m) (m) (m) Shoulder (m) Subject First Second First Second First Second First Second First Second Seating Seating Seating Seating Seating Seating Seating Seating Seating Seating System System System System System System System System System Tested Tested Tested Tested Tested Tested Tested Tested 1 .0. 048 _Q.Il3S 0 031 0 682 0.695 1.219 0.22S 105 0 110 3 2_ 0 055 0.067 0.1 1 E ,6 06: 5 3 0,03 0 .031: I .OS:: 1 .0251 1 032 _1 _1 1.065 0.024 _0.68E a: io1 0.619 a: 0.034 0.020 0.009 0 026 0.604 0.755 0.415 0.519 78. 8 18.< 9 0 038 0.033 0.043 0.01 1.700 0 658 0.202 1 190 t23. 115. 10 0.012 0.012 0 010 0 01' 0.782 0 738 0 212 1 200 103.8 97. 9 Results !Average 0 .0421 0 .0371 0.0481 0 .0391 1.67' 0.6901 1 .2741 1 .2901 101.71 103.8 IS!dDev 0.019 1 1.0191 0 .0331 0 .0241 1 .0831 0 .0761 1 .1191 0.151 13.31 8 0 .0331 1.5:f. 0 .8911 1 .8001 1 .5841 0.2681 2 .0811 1 .7931 -0.2311 0 .9701 Parametric : T -Test 0.421 0 .491 0.390 0.236 0.481 0.441 0 732 0.414 0.432 0.563 180

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Table K.5. (Cont.) Elliptical Path Task Results from the Comparison Group. Order Performed Comparison. Angle Deviation (0 ) Knee Angle (") Dominant Leg Non-Dominant Leg Subject First Second First Second First Second Seating seating Seating Seating Seating Seating System System System System System System Tested Tested Tested Tested Tested Tested 1 82.5 89.2 .21 -3.41 2.94 2.63 2 101.0 87.9 .09 -3.04 2.57 2.47 3 115.3 102.6 48 -3.40 2.81 2.92 4 79.7 n.4 .85 .21 2.58 2.30 5 57 1 55.7 -3 .11 55 2.96 2.45 6 103.8 84.3 -3 24 .81 3.24 2 48 7 86 3 96.8 97 -3.25 2 42 3.41 8 82.5 79. 7 32 .24 2 56 1.68 9 n.7 88.6 -2.73 -2.68 1.88 3.10 10 97.6 83.0 -2.97 -3.18 3 60 2.01 Results Average 88.4 84.5 -2.7 -2.9 2 8 2.5 Sid Dev J 16 5 12.61 0 .41 0 .41 0.51 0.5 Skev.Tless I -0.2081 -1.1271 0.281 0 .3321 0 017 0.063 Comparison p-values Parametric: T-Test 0.294 0.411 0.449 Non-Parametric: 0.543 0.459 0.501 Wilcoxon K.2.3 Can Stacking Task Table K.6. Can Stacking Task Results from the Comparison Group. Order Performed Comparison. Can Stacking Completion Time (s) Subject Order Performed Comparison First Seating Second Sealing System Tested 1 4 09 4.08 2 3 39 3 09 3 4 23 4.37 4 3 33 2 85 5 3.43 3.42 6 3.45 3.43 7 3.82 3.14 8 3.73 3.53 9 3.76 3.6 10 4.13 3.48 Results 3.74 3 50 Sid Dev I 0.33 0.45 Skev.ness 0 252 0.707 Com_11_8rison p-values Parametric: T-Test 0.027 Non-Parametric: 0.017 Wilcoxon 181

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