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THE SHORT-TERM EFFECT OF A ROLLATOR ON FUNCTIONAL EXERCISE
CAPACITY IN INDIVIDUALS WITH SEVERE CHRONIC OBSTRUCTIVE
PULMONARY DISEASE
Sherra Beth Solway
A thesis submitted in conformity with the requirements
for the degree of Masten of Science
Graduate Department of Rehabilitation Science,
University of Toronto
@Copyright By Sherra Beth Solway 2001
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ABSTRACT
The Short-Term Effect of a Rollator on Functional Exercise Capacity in Individuals
with Severe Chronic Obstructive Pulmonary Disease
Sherra Beth Solway, M.Sc. (2001)
Graduate Department of Rehabilitation Science
University of Toronto
Purpose: This study was conducted to examine the effect of a rollator on functionai exercise
capacity in individuals with severe COPD and to determine which individuals would benefit
most from using a rollator. Methods: 40 subjects were studied on wo separate days in the
same week. Two six-minute walk tests (6MWTs) were performed on each day. One 6MWT
was performed unaided and the other using a rollator, with the order of the test randomized
on the fint day and revened on the second. Results: There was a significant reduction in
modified Borg rating of dyspnea (pe0.001) and duration of rest (p=0.001) with use of the
rollator. For subjects who walked less than 300 meten unaided, there was also a significant
improvement in distance waked (p4.02). Requirement of a rest during the unaided 6MWT
was the only significant predictor variable for irnprovement in functional exercise capacity
with use of the rollator (p<0.005). Conclusions: Rollators are effective in improving
fùnctional exercise capacity by reducing perception of dyspnea and rest duration in
individuals with severe COPD. hdividuals who walk less than 300 meters ancilor who
require a rest during an unaided 6 W will benefit most kom using a rollator in ternis of
reductions in breathlessness and rest time and an improvement in distance walked.
In Loving Memory of iny Nana M d y
. S .
I l l
ACKNOWLEDGEMENTS
During the process of this research project, many individuals gave time, guidance and emotional support. To al1 of these people, 1 offer my sincere gratitude and appreciation.
My special thanks to:
Dr. Dina Brooks, for sharing her knowledge, expertise and own expenences; for coaching me through each stage of my studies; and for providing encouragement when I rnost needed it. Without her guidance, participation and mentoring, this endeavor would not have been possible;
Drs. Cheryl Con, Roger Goldstein and Scott Thomas, for sharing thcir expertise, reviewing my thesis and providing constructive feedback;
Dr. Scott Thomas, in his role as Graduate Coordinator, for his understanding, support, guidance and encouragement;
Louis Lau for his technical expertise and knowledge and his assistance and contributions to the study;
David I. Wang, for his assistance with data analysis,
Donna Clow for her support, kindness and assistance with subject recruitment;
The Day Hospital, 2WF and Respiratory Medicine staff at West Park Health Hospital for their support and assistance;
Glavo Wellcome, The Clinical Evaluation and Research Unit at West Park Hospital, the Ontario Ministry of Education and Training, the Ontario Respiratory Care Society and the Canadian Physiotherapy Cardiorespiratory Society for their financial support;
My brother Lome, for his words of encouragement and unwavering support;
And finally, the individuals who participated in this study, for their time, kindness and genuine desire to help othen.
ABBREVIATIONS
SMWT
6MWT
ISMWT
ABG
ANOVA
ATS-DLD
BDI
bpm
CF
cm
CI
cm
COPD
CHQ
CRQ
DLCO
EMG
ESLD
FEV,
FRC
FVC
ICC
Two-Minute Walk Test
Six-Minute Walk Test
Twelve-Minute Walk Test
Arteriai BIood Gases
Analysis of Variance
Amencan Thoracic Society. Division of Lung Diseases
Baseiine Dyspnea Index
beats per minute
Cystic Fibroçis
Congestive or Chmnic Head Failure
Confidence Interval
Centimeters
Chronic Obstructive Pulmonary Disease
Chronic Heart Failure Questionnaire
Chronic Respiratory Disease Questionnaire
Difision Capacity of Carbon Monoxide
Electromyography
End Stage Lung Disease
Forced Expiratory Volume in One Second
Functional Residual Capacity
Forced Vital Capacity
Intra-Class Correlation Coefficient
NC
Kg
m
min
ME'
mL
MRC
L
NYHA
NPV
NR
NS
0 2
P m
PaOr
PEFR
PFT
PPV
r
R
ROC
RPE
RV
Inspiratory Vital Capacity
Kilograms
Meters
Minutes
Maximal lnspiratory Pressure
Millilitres
Medical Research Council
Litres
New York Heart Association
Negative Predictive Value
No Rollator
Not Signi ficant
Ox y gen
Peripheral Merial Disease
Partial Pressure of Oxygen
Peak Expiratory Flow Rate
Pulmonary Function Tests
Positive Predictive Value
Pearson's Correlation Coefficient
Rollator
Receiver Operating Charactenstic
Rating of Perceived Exertion
Residual Volume
SAS
SD
SE
SGRQ
SIP
SOLVD
TLC
VAS
VC
VE
VI
VO2
VOzmav
WI
VVIR
Wmaii
wrt
Percent Saturation of Hemoglobin with Oxygen in Artenal
Blood
Specific Activity Scde
Standard Deviation
S tandard E rro r
Si. George's Respiratory Diseases Questionnaire
Sickness impact Profile
Studies of Lefi Ventricular Dysfunction
Total Lung Capacity
Visual Analogue Scale
Vital Capacity
Minute Ventilation
Virtual Instrument
Oxygen Consumption
Maximal Oxygen Consumption
Fixed Rate Response
Optimal Rate Response
Maximal Work Capacity
With Respect To
vii
Pape Number
Abstract Acknowledgernents Ab breviations List of Tables List of Figures List of Appendices
Chapter 1 : Introduction and Review of Literature
1.1 Background and Purpose of Study
l .Z Chronic Obstructive Puimonary Disease (COPD): An Overview 1.2.1 Review and Definition of COPD 1.2.2 Prevalence of COPD 1.2.3 Pathophysiology of COPD 1.2.4 Respiratory Rehabilitation in COPD
1.3 Use of Wheeled Walkers and Roliators 1.3.1 Wheeled Walkers and Rollators in Individuals with
COPD 1.3.2 Wheeled Walkers and Rollators in Older Adults and
the Elderly 1.3.3 Potential Mechanisms of Improvernent in Functional
Exercise Capacity with Use of a Wheeled Walker or Rollator
1.3.4 Summary
Walk Test Measures of Functional Exercise Capacity in lhdividuals with Cardiorespiratory Disease
1.4.1 Definition 1.4.2 Two-Minute Walk Test 1.4.3 Six-Minute Walk Test 1.4.4 Twelve-Minute Walk Test 1.4.5 Factors Affecting Performance 1.4.6 Summary
. . i l
iv v xi xii ~ i v
1.5 Research Questions and Hypotheses
Chapter 2: Methods 36
2.1 Subjects 2.1.1 Sampling and Recruitrnent 2.1.2 Inclusion and Exclusion Criteria
2.2 Study Design 37 2.2.1 ProtocoI 37 2.2.2 Data Acquisition 39 3.2.3 Measures 42
2.2.3.1 Primary Measures 42 2.2.3.1 a Six-Minute Walk Test Distance 42 2.2.3.1 b Modified Borg Rating of Dyspnea 43
2.2.3.2 Secondary Measures 44 2.2.3.2a Measures of Cardiorespiratory Function 44
2.2.3.2ai Ventilatory Variables 44 2.2.3.2aii Oxygen Saturation and 46
Heart-Rate 2.2.3.3b Measures of Gait 47
2.2.3.2bi Number of Stides/Stride Length 47 2.2.3.2bii Overall Walking Speed 47 2.2.3.2biii Modified Borg Ratings of Leg 47
Discom fort 2.2.3.3 Explanatory Descriptive Measures 48
2.2.3.3a Upper Extremity Weight-Bearing 48 2.2.3.3b Subject Preference 49 2.2.3.3~ Health-Related Quality of Life 49
2.2.4 Data Processing 50 2.2.5 Statistical Analysis 5 1
Chapter 3: Results 53
3.1 Sample Characteristics 53
3.2 Prirnary Outcomes 3 2.1 Six-Minute Walk Test Distance 3 2.2 Duration of Rest 3.2.3 Modified Borg Rating of Dyspnea
3.3 Secondary Outcomes 3.3.1 Cardiorespiratory Function
3.3.1.1 Ventilatory Variables 3.3.1.2 Oxygen Saturation and Heart-Rate
3.3.2 Gait 67 3.3.2.1 Stride Length 67 3.3.2.2 Overall Walking Speed 67 3.3.2.3 Modified Borg Rating of Leg Discornfort 72
3.4 Explanatory Descriptive Measures 72 3.4.1 Baseline (Le. Unaided) Six-Minute Walk Test Distance 72 3 .4.2 Upper Extremity Weight-Bearing 75 3.4.3 Subject Pre ference 78 3 4.4 Univariate Regression Analysis 79 3.4.5 Mulivariate Regression Analysis 80
Chapter 4: Discussion 82
4.2 Cornparisons to Other Studies 83
1.3 Research Questions 1 & 2 - Determining the Effect of a Rollator on 86 Functional Exercise Capacity and Individuals Who Benefit Most 4.3.1 Clinical Implications of Findings 88
4.4 Research Question 3 - Insight into Mechanisms 89
4.5 Limitations 93
Chapter 5: Conclusions and Recommendations for Future Research 96
5.1 Conc luding Remarks 96
5.2 Future Researcti 96
REFERENCES 98
APPENDICES 111
LIST OF TABLES
Table Descri~tion Pape
Guidelines for hterpreting FEV
Studies of Psychometric Properties of the Two-Minute Walk Test.
Studies of Psychometric Properties of the Six-Minute Walk Test in Patients with Chronic Obstructive Pulmonary Disease.
Studies of Psychometric Properties of the Six-Minute Walk Test in Patents with Heart Failure.
Other Studies of Psychometric Properties of the Six-Minute Walk Test.
Studies of Psychometric Properties of the Twelve-Minute Walk Test.
Surnmary of the Evidence for the Psychometric Properties of the Two, Six, and Twelve Minute Walk Tests.
Data Acquisition Channels.
Classification of Measures.
General Characteristics of Sarnple.
Pre- and Post-Test Ratings of Dyspnea Using the Modified Borg Scale
Amount of Upper Extremity Weight-Bearing Dunng Each Minute of the Six-Minute Walk Test.
Agreement with Statements Pertaining to Use of the Rollator During the Six-Minute Walk Test for the Total Sarnple.
Subject Preference Categorized According to Level of Disability
Univariate Regression Analysis Between Potential Predictor Variables and Improvement in Functional Exercise Capacity with Rollator
Multiple Regression Analysis Between Predictor Variables Identified with Simple Linear Regression and Improvement in Functional Exercise Capacity with Rollator.
LIST OF FIGURES
Fipu - r e Descri~tion Pape
1 Photograph of tester's trolley set-up with monitoring and acquisition equiprnent.
Comparison of total distance walked unaided and with the rollator.
3 Distance walked unaided and with the rollator for each minute of the six-minute walk test for the total sarnple and for subjects who walked less than and greater than 300 meten unaided
4 Cornparison of duration of rest during the six-minute walk test when walking unaided and with the rollator.
5 Cornparison of change in perception of dyspnea when walking unaided and with the rollator.
6 Cornparison of respiratory rate during the six-minute walk test when walking unaided and with the rollator.
Cornparison of the phase relationship of the nb cage and abdomen during the six-minute walk test when walking unaided and with the rollator.
Comparison of minute volume during the six-minute walk test when walking unaided and with the rollator.
Comparison of the ratio of the contribution of breathing of the rib cage to the abdomen during the six-minute walk test when walking unaided and with the rollator.
Comparison of oxygen saturation during the six-minute walk test when walking unaided and with the rollator.
Comparison of heart-rate during the six-minute walk test when walking unaided and with the rollator.
Cornparison of stride length during the six-minute walk test when walking unaided and with the rollator.
Comparison of overall w&g speed during the six-minute walk test when walking unaided and with the rollator.
xii
Fipure des cri^ tion Pape
14 Cornparison of change in perception of leg discomfort when walking unaided and with the rollator.
15 Scatter plot showing the relationship between baseline measure of disability and change in distance waiked with the rollator.
16 Relationship between amount of weight applied to rollator and change in distance waiked with the rollator.
17 Relationship between amount of weight applied to rollator and change in perception of dyspnea with the rollator.
I Voltage spikes denoting contact of heel with ground during ambulation.
II Relationship between known weights applied to rollator and output of weight-bearing sensing mechanism.
LIST OF APPENDICES
Amendix Descri~tion Pape
1 Eligibility Screening Form 111
7 - Subject Information Sheet and Informed Consent Form 113
Data Collection Forrn
Modified Borg Scale
Equations for Respiratory inductance Plethysmography 121 CaIibration
6 Stride Sensor Output 123
7 Validation of Weight-Bearing Sensing Mechanism. 125
8 Subject Preference Questionnaire 127
9 St. George's Respiratory Questionnaire 130
10 Calculation Procedure for Phase Angles 136
11 Normal Respiratory Data 138
xiv
Chapter 1: Introduction and Review of Literature
1.1 Backpround and Pur~ose of Studv -
The purpose of this study was to: 1) evaluate the short-term effect of using a rollator
on hct ional exercise capacity in individuals with Chronic Obstructive Puhonary Disease
(COPD), 2) assess which individuals with COPD would benefit most fiom using a rollator
and 3) examine the underlying rnechanisms that may contribute to change in functional
exercise capacity with use of a rollator. In this introduction, I will provide overviews of
COPD, wheeled walking aids and functional waik tests and will discuss the background and
rationale for this work.
1.2 Chronic Obstructive Pulmouarv Disease (COPD): An Overview -
1.2.1 Review and Definition of COPD
COPD is a chronic, slowly progressive disease characterized by irrevenible airfiow
obstruction secondaiy to chronic bronchitis and/or emphysema (Canadian Respiratory
Review Panel, 1998; The COPD Guidelines Group, 1997; Jenkins et al., 1995; Siafakas et al.,
1995). Cigarette smoking and exposure to tobacco smoke are the primary causes of COPD
(Canadian Respiratory Review Panel, 1998; The COPD Guidelines Group, 1997; Jenkins et
al., 1995; Siafakas et al., 1995). Chronic bronchitis is defined in dinical terms as the
presence of a productive cou& for at least three months per year for a minimum of two
consecutive years. in contrast, emphysema is defined in pathological ternis as enlargement
and destruction of the alveoli and respiratory bronchioles (Canadian Respiratory Review
Panel, 1998; Siafakas et al., 1995). Most individuals with COPD have some combination of
chronic bronchitis and emphysema (Harnmon & Hasson, 1996). Other specific causes of
airflow limitation such as cystic fibrosis, asthma, bronchiectasis and bronchiolitis obliterans
are not included in the definition of COPD by convention (Canadian Respiratory Review
Panel, 1998; Siafakas et al., 1995). However, many individuals with COPD have some
degree of revenible ainvay obstruction secondary to inflammation (Canadian Respiratory
Review Panel, 1998; Murray & Petty, 1996; Siafakas et al., 1995).
A diagnosis of COPD requires a history of progressive cough, wheeze or dyspnea and
objective evidence (i.e. spirometic testing) of airway obstruction that does not retum to
normal with treatrnent (Canadian Respiratory Review Panel, 1998; The COPD Guidelines
Group, 1997; Jenkins et al., 1995). There are three stages of COPD; namely, mild, moderate
and severe. Forced expiratory volume in one second (FEV,) is the accepted guide to
diagnosis and severity of COPD and is defined as the maximal volume of air exhaled during
the fint second (Amencan Thoracic Society, 1999; The Canadian Respiratory Review Panel,
1998; The COPD Guidelines Group, 1997). Individuals with COPD show a decline in FEVl
of approximately 48-91mL per year (Kim et al., 1991; Snider et al., 1985), which is
significantly higher than the normal rate of decline due to aging, Le. 20-30mL per year
(Canadian Respiratory Review Panel, 1998; Siafakas et al., 1995). Although, ihere is general
acceptance that a FEVl of less than 35% predicted is representative of severe airway disease,
curent guidelines for interpreting FEVi are conflicting (The COPD Guidelines Group, 1997;
Amencan Thoracic Society, 1995; Siafakas et al., 1995). These guidelines are shown in table
1.
Table 1: Guideünes for Interpreting FEV,
1 Author 1 Mild COPD 1 Moderate COPD 1 Severe COPD
Il American Thoracic 1 FEV, 2 50% predicted FEV, 35-49% predicted FEVl < 35% Societv. 1995 1 1 ~redictcd
II Siafakas et al.. 1995 1 FEV, 2 70% predicted 1 FEV, 50-69% predicted 1 FEVl < 50%
COPD Guidelines
Clinically, individuals with mild COPD tend to be asymptomatic or present with rnild
symptoms such as rnorning cough, recurrent respiratory infections or shortness of breath with
significant exertion (Canadian Respiratory Review Panel. 1998; The COPD Guidelines
Group, 1997). Individuals with moderate COPD can present with cough and sputurn
production, dyspnea on moderate exertion, signs of hypennflation and/or recurrent
exacerbations (Canadian Respiratory Review Panel, 1998; The COPD Guidelines Group,
1997). Finally, individuals with severe COPD tend to be disabled by severe dyspnea at rest
or with minimal activity. These individuals typically experience recurrent exacerbations,
which are often complicated by respiratory andior heart failure (Canadian Respiratory
Review Panel, 1998; The COPD Guidelines Group, 1997). In al1 stages of COPD, dyspnea is
the primary activity limiting symptom leading to reduced functional ability. (Jenkins et al.,
1995; Breslin, 1992).
There is no cure for COPD; however, disease progression and clinical detenoration
can be slowed by several management strategies including smoking cessation, dmg therapy
(Le. bronchodilaton, corticosteroids), nutrition, influenza vaccinations, oxygen therapy and
respiratory rehabilitation (Canadian Respiratory Review Panel, 1998; The COPD Guidelines
predicted
Group of the Standards of Care Cornmittee of the , BTS, 1997
FEV, 60-79% predicted FEV, 40-59% predicted F E V V 1 4 0 % predicted
Group, 1997; Jenkins et al., 1995; Siafakas et al., 1995). There are various published clinical
practice guidelines on the assessrnent and management of COPD; however, differences exist
with respect to content and emphasis (Lacasse et al., In Press; Jones, 1999).
1.2.2 Prevalence of COPD
There is evidence for the increasing economic and social burden of COPD resulting
from its increasing prevalence and significant morbidity (Calverley, 2000a). COPD is the
fifth leading cause of death in North Amenca (Canadian Respiratory Review Panel, 1998;
Canadian Thoracic Society Workshop Group, 1992; Feinleib et al., 1989). A recent analysis
of trends in the epidemiology of COPD in Canada estimated that 750,000 Canadians had
chronic bronchitis or emphysema diagnosed by a health care professional (Lacasse et al.,
1999). Prevalence rates for 1994 to 1995 were estimated to be 4.7% for individuals aged 55
to 64 years, 5.4% for individuals aged 65 to 74 years and 8.3% for those 75 years of age and
older (Lacasse et al., 1999). The prevalence o f the disease was f o n d to be higher for men
then women in al1 age categories (Lacasse et al., 1999). Given that there has been an
increase in female srnoken, the prevalence of COPD in women will continue to nse
(Canadian Respiratory Review Panel, 1998). Similar epidemiological findings have been
reported in the United States and Europe (Gulsvik, 1999; National Centre for Health
Statistics, 1993).
1.2.3 Pathophysiology of COPD
The bronchial tree and alveoli are the sites of pathological changes that occur with
COPD (The COPD Guidelines Group, 1997). The small bronchi and bronchioles are the
main areas of airflow resistance (Siafakas et al., 1995). The pathophysiologic processes
associated with COPD include inflammation of the airways, enlarged submucosal glands and
goblet ce11 hyperplasia resulting in mucosal hypenecretion and ciliary dysfunction, and
proteolytic destruction of the alveoli and comective tissue framework of the lung (Jenkins et
al., 1995; Siafakas et al., 1995; Canadian Thoracic Society Workshop Group, 1992). As a
result of these changes, airway diameten narmw, elastic recoil of the lungs is lost and small
ainvay collapse is potentiated. Therefore, airflow limitation and hypennflation occur
(Jenkins et al., 1995; Siafakas et al., 1995; Canadian Thoracic Society Workshop Group,
1992). An individual's clinical presentation is determined by the pathological processes that
predominate (Siafakas et al., 1 995).
Changes also occur in the pulmonary circulation and in severe disease, in the right
heart (Siafakas et al., 1995). Airflow limitation and alveolar darnage results in a mismatch of
ventilation and perfusion, which therefore impairs gas exchange (Siafakas et al., 1995).
Chronic impairnent of gas exchange can lead to polycythemia and vasoconstriction with a
resultant increase in vascular pulrnonary resistance (Siafakas et al., 1995; Snider et al., 1994).
Pulmonary hypertension may result in enlargement and failure of the nght ventncle of the
heart (Le. cor pulmonale) (Canadian Respiratory Review Panel, 1998; Murray & Petty,
1996).
Lastly, individuals with COPD show distinguishing changes in lung volumes.
Functional residual capacity (FRC), residual volume (RV) and the ratio of RV to total lung
capacity (TLC) increase while vital capacity (VC) diminishes (Siafakas et al., 1995). FRC
increases because of the loss of lung elastic recoil and due to dynamic factors at the end of
expiration, especially when ventilation is increased (Siafakas et al., 1995; Stubbing et al.,
1980). Specifically, because of airflow limitation, the rate of expiration is slowed and the
time between subsequent inspirations does not allow full expiration to occur (O'DomelI,
1998; Siafakas et al., 1995). The term "dynamic pulmonary hypennflation" is used to
describe ihis process (O'Donnell, 1998; Siaf 'as et al., 1995). The hypennflation results in
increased work of breathing and higher energy consurnption of the inspiratory muscles than
in healthy individuals (Siafakas et al., 1995). Additionally, the function of the diaphragrn
and other inspiratory muscles becomes cornpromised because of unfavorable length tension
relationships (O'Donnell, 1998; Delgado et al., 1982).
1.2.4 Respiratory Rehabilitation in COPD
Respiratory rehabilitation is a therapeutic approach provided by an interdisciplinary
team of health care professionals and directed to penons with respiratory disease and their
farnilies (Fishman, 1994). Typical components inciude patient and family education, aerobic
exercise, breathing retraining, upper extremity endurance and strengthening exercises, energy
conservation and psychosocial support (Arnencan Thoracic Society, 1999; Lacasse et al.,
1997a; Ries et al., 1995; Canadian Thoracic Society Workshop Group, 1992). Prograrns are
usuaily of at least four weeks duration and occur in both hospital based (i.e. in-patient and
out-patient) and cornmunity based settings (American nioracic Society, 1999; Lacasse et al.,
1996). Lacasse and colleagues (1996) established the efficacy of respiratory rehabilitation
(i.e. programs of at least 4 weeks duration with or without education andfor psychosocial
support) on functional exercise capacity and health-related quality of life in individuals with
COPD using a rneta-analysis.
Exercise training has been shown to be fundamental to respiratory rehabilitation
(Arnerican Thoracic Society, 1999; Lacasse et al., 1997a; Lacasse et al., 1996). Most
respiratory rehabilitation prognms emphasize endurance training at levels of 60% of
maximal workload; for those who cannot tolerate this intensity, interval training is utilized
(Arnerican Thoracic Society, 1999). Although upper extremity endurance training has been
shown to be effective in improving arm function, few studies have evaluated the
effectiveness of strength training in individuals with COPD (Arnerican Thoracic Society,
1999; Lacasse et al., 1997a)
The additional benefit of breathing retraining, education and psychosocial support to
exercise training is not well evidenced (American Thoracic Society, 1999; Lacasse et al.,
1997a). The effectiveness of inspiratory muscle training and other breathing exercises as an
adjunct to exercise training for individuals with COPD is uncertain and the contribution of
education has not been well addressed in the literanire (American Thoracic Society, 1999;
Lacasse et al., 1997a). Dyspnea management strategies alone have not been s h o w to be
effective in improving dyspnea, exercise capacity or health-related quality of life (Lacasse et
al., 1997a). Psychosocial support has been shown to have a positive short-term effect on
dyspnea and when incorporated into a respiratory rehabilitation program, may promote
cornpliance with exercise training and improve health-related quality of life (Lacasse et al.,
1997a).
The primary goal of respiratory rehabilitation is for individuals to achieve and
maintain their maximum level of independence and functioning in the community (Fishman,
1994). As a result of their severe disease, individuals with COPD are often disabled due to
dyspnea and poor functional exercise capacity (Canadian Respiratory Review Panel, 1998).
These individuals tend to adopt sedentary lifestyles which results in M e r deconditioning,
worsening of symptoms and reduced quality of life (Canadian Respiratory Review Panel,
1998). The underlying rationale for respiratory rehabilitation is to prevent deconditioning
and allow an individual to cope with hidher disease (The COPD Guidelines Group, 1997).
Walking is an important, useful and preferred form of exercise for rnost individuals
with COPD (American Thoracic Society, 1999; Murray & Petty, 1996). As such, it is
incorporated into the majority of respiratory rehabilitation programs by means of evaluation
and treamient (Brooks et al., 1999; Murray & Petty, 1996; Siafakas et al., 1995; Canadian
Thoracic Society Workshop Group, 1992). in those individuals with severe lung disease, a
wheeled walking aid is oflen used for the walking component in order to reduce dyspnea and
improve hct ional capacity (Honeyman et al., 1996). However, there is limited literature on
the effectiveness of walking aids for individuals with COPD.
1.3 Use of WheeIed Walkers and Rollators -
Ambulatory aids such as wheeled walken and rollaton can be used to reduce walking
disability in individuals with COPD and the elderly (Comely, 1998; Roomi et al., 1998;
Verbrugge et al., 1997; Honeyman et al., 1996; Wesmiller & H o h a n , 1994). Wheeled
walkers are wdker Frames with two, three or four standard wheels. While a rollator is also
considered a walker with four wheels, the front two wheels typically are on swivel castes for
easy maneuverability (Comely, 1998). Additionally, unlike regular wheeled waiken,
rollaton are equipped with hand brakes, a basket for carrying objects and a fold-dom seat
that allows an individual to rest at any place or time. Although the superionty of wheeled
waiken to standard waiken (i.e. without wheels) for improving functional ability is
evidenced in the literature (Bohannon, 1997; Medley & Thompson, 1997; Foley et al., 1996;
Harnzeh et al., 1988). the use and effect of wheeled walkers and rollaton on functional
capacity and activities of daily living has not been extensively studied.
1.3.1 Wheeled Walkers and Roltators in Individuals with COPD
Only five fùlly published reports and one abstract could be f o n d on the effeci of
wheeled waiking aids in individuals with COPD. In 1957, Campbell descnbed the effect of
leaning on a modified "dressing trolley" on exercise tolerance in one individual with severe
emphysema. A six to ten-fold increase in exercise tolerance was reported. Similarly, in
1972, Grant and Cape1 studied the effect of a wheeled walking aid in five individuals with
severe pulmonary emphysema. These authors found a two-fold increase in walking distance
associated with a twenty-nine percent reduction in walking velocity and no significant
change in minute ventilation. The improvement in w a k n g distance was achieved by an
increase in endurance as subjects were not limited by time. In contrast, Wesmiller and
H o f i a n (1994) found no statisticaily significant change in waUUng distance with the use of
an assistive device with wheels in twelve oxygen-dependent men with severe COPD.
However, a significant difference in waiking distance was f o n d in a subgroup of six
individuals who were the most disabled (twelve-minute walk test distance less than 1000
feet). Although this study utilized a modified version of the twelve-minute walk test and a
standardized instruction protocol, repeated measurements of w a h g distance to control for
order and day were not perforrned nor were measurements of dyspnea or oxygenation taken.
Furthemore, the height of the mobility aid was adjusted for cornfort rather than being
standardized. In an abstract by Dalton and colleagues (1995), the use of a wheeled walker
was reported to result in a significant reduction in dyspnea in ten individuals with severe
COPD; however, no significant change in six-minute waik test distance or oxygen saturation
was observed. A more recent study by Honeyman and colleagues (1996) exarnined the effect
of a rollator on distance walked, oxygen saturation and breathlessness using a six-minute
walk test. In their sarnple of eleven individuals with significant disability (i.e. six-minute
walk test distance less than 300 meters) secondary to severe COPD, the use of a rollator
resulted in a statistically significant increase in six-minute walking distance (Le. 33.6
meten), reduction in hypoxemia (Le. 2.2%) and decrease in dyspnea (i.e. 1.3 units) as
determined by the modified Borg scale. Five of these subjects required oxygen for exertion
and were required to pull their oxygen canister during their unaided walk only. Improvement
with use of the rollator may have occurred because of a reduction in the metabolic cost of
activity in individuals using oxygen not having to pull their portable cylinder (Honeyman et
al, 1996). Finally, Roomi and colleagues (1998) compared walking unaided with three
different mobility devices (Le. standard walker, rollator, and hi&-wheeled walker) in twenty-
seven elderly individuals with COPD. They found that only the high-wheeled walker had a
positive effect on six-minute walk test distance and oxygen saturation.
In summary, the available literature on the effectiveness of wheeled walking aids in
individuals with COPD is not extensive and conflicting. Given that most individuals with
COPD are greater than fi@-five years of age (Lacasse et al., 1999; Murray & Petty, 1996),
the literature on the use of wheeled walking aids in older adults and the elderly will also be
examined.
1.3.2 Wheeled Walkers and Rollators in Older Adults and the Elderly
Four studies were f o n d comparing and evaluating the effects of wheeled waiken on
fùnctional ability in older adults and the elderly. A study by Mahoney and colleagues (1992)
compared performance with a two venus a three-wheeled walker in a sample of elderly
subjects and showed that the three-wheeled walker resulted in longer stnde lengths and faster
obstacle course coverage. In 1993, a study by Tideiksaar compared a two-wheeled walker
and a four-wheeled walker and found that the four-wheeled walker provided improved
mobility, easier tuming and greater overall satisfaction in a sarnple of twenty non-
institutionalized elderly individuals. Likewise, Comely and colleagues (1997) investigated
ambulation variables and user preference on a variety of terrains with a two-wheeled walker
compared to that of a rollator in a mixed sample of healthy adults and elderly. Faster
waiking speeds, longer walking distances, greater comfort and stability as well as better
maneuverability were found with the rollator. Most recently, Comely (1998) reported on a
case of a 68 year old man with a decline in fùnction secondary to renal failure, pancreatitis
and respiratory failure. Although this individual was accustomed to using a standard walker
and had a trial with a two-wheeled walker, he did not expenence ciramatic functional
improvement (e.g. comrnunity ambulation) until he was given a rollator. Reasons cited for
this improvement were reduced upper extremity pain, less physical exertion to advance the
rollator and the presence of a seat, which provided confidence and security.
1.3.3 Potential Mechanisms of Improvement in Functional Exercise Capacity
for Individuals with COPD with Use of a Wtieeled Walker or Roiiator
Various mechanisms have been postulated to contribute to improvement in
functional capacity with a wheeled walking aid in individuals with COPD (Honeyman et al.,
1996; Campbell, 195 7). Support of the upper extrernities, postural changes and alterations in
gait have al1 been postulated as changes that will reduce metabolic and ventilatory demands
and facilitate the function of the diaphragm and accessory muscles of breathing. These
changes potentially cm reduce exertional dyspnea for a given activity level and therefore
increase fùnctional exercise capacity (O'Donnell. 1998).
Several studies have compared the effect of supported versus non-supported
arms during treadrnill walking and have shown increases in exercise capacity with arm
support (McComell et al., 1991; Parrillo et al., 1991; Von Duvillard & Pivirotto, 1991;
McComell & Clark, 1987; Zeimetl et al., 1985). Pari110 and colleagues (1991) used a
specially designed treadrnill apparatus, which required 5 kilograms of resistive force by hand
compression for the supported am trial. They found that non-supported walking resulted in
significantly greater metabolic, ventilatory and cardiovascular demands. Significant
decreases in oxygen consumption, minute ventilation and heart-rate were observed using
hand-rail support. Several other investigations have reported similar findings and have also
s h o w increases in exercise capacity when handrail support was used (McConnell et al.,
1992 ; Von Duvillard & Pivirotto, 1991; McConnell & Clark, 1987; Zeimetz et al., 1985).
Zeimetz and colleagues (1985) M e r determined that oxygen consumption decreased as
force on the handrails increased and established that depending of the amount of force
exerted during arm support, there was as much as a 30% change in oxygen consumption at a
given workload when compared to no arm support. None of these investigations used
subjects with COPD. Although the provision of arm support with treadmill wallcing reduces
metabolic and ventilatory demands in healthy individuals, the effect of upper extremity
support on the perception of dyspnea has not been investigated (Breslin, 1992).
Many individuals with COPD sit in a fonvard leaning position supporting their upper
extremities on some fixed object in order to relieve their shortness of breath (Sharp et al.,
1980). Barach (1974) and Sharp and colleagues (1980) studied the effect of several body
positions in individuals with severe COPD and determined that the leaning fonvard position
did result in a reduction in the perception of dyspnea. Delgado and colleagues (1982)
m e r observed that when individuals with COPD exercised on the treadmill in a fonvard
lean position, exercise endurance improved. The postural relief of dyspnea and improvement
in exercise endurance was suggested to be related to the increased effectiveness of the
diaphragm (Delgado et al.. 1982; Sharp et al., 1980; Barach, 1974). Hyperinflation results in
shortening of the diaphragm's muscle fiben (Le. flattening) and a resultant reduciion in the
diaphragm's tension-generating capability (Sharp et al., 1980; Barach, 1974). The forward
lean position induces abdominal compression, which is thought to stretch the diaphragm
upward and improve its tension generating capability (Sharp et al., 1980).
A further effect of leaning forward, particularly when the upper extrernities are
stabilized, may be to increase the effectiveness or efficiency of the accessory muscles of
breathing (Sharp et al., 1980). The accessory muscles of breathing have roles in both the
maintenance of ventilation and the stabilization of the chest wall during unsupported arm
exercise (Breslin, 1992). Although walking is primarily a lower extremity activity,
unsupported arm swing occurs. When the arms are not supported, the accessory muscles are
required to participate in postural support of the arms and torso and therefore may decrease
their effectiveness in contributing to ventilation (Breslin & Garoutte, 1995; Celli et al.,
1986). This rnay place greater demand on the diaphragm and rnay lead to earlier diaphragm
fatigue (Breslin & Garoutte, 1995; Celli et al., 1986). Support of the arms allows muscles
attached to the shoulder girdle to act more effectively as accessory muscles of breathing
(Banzett et al., 1988).
Although no investigation has evaluated these postulations using a wallcing aid,
several researchers have suggested that the forward lean position that individuals adopt when
using a rollator rnay allow the diaphragm and accessory muscles to optimally contribute to
ventilation (Roomi et al., 1998; Honeyman et al., 1996; Wesmiller & HoMnan, 1994). There
is an inverse association between dyspnea and diaphragm activity and a positive correlation
between dyspnea and accessory muscle recmitment (Breslin et al., 1990). If a shift in the
work of breathing from the accessory muscles to the diaphragm occun, reductions in
dyspnea and minute ventilation and an increase in functional exercise capacity rnay occur.
There are two other potential mechanisms that have received minimal attention in the
literature. First, increased security provided by the rollator rnay decrease fear and anxiety and
consequently rnay reduce shortness of breath and increase functional exercise capacity.
Second, increases in walking distance with use of a wheeled walking aid in individuals with
COPD have been associated with reductions in walking speed (Grant & Capel, 1972). Use of
the rollator rnay promote individuals to reduce their walking speed, thereby, facilitating
pacing and increasing functional exercise performance.
1.3.4 Summary
Rollatoa are O ften prescnbed for individuals with COPD. However, evidence
regarding their effectiveness is limited and does not allow us to adequately determine the
effect of a rollator on functional exercise capacity in this population. Since the primary
objective of this study was to investigate this issue, it was necessary to determine the best
measure of functional exercise capacity for individuals with COPD. In view of the various
measures of functional exercise capacity available (e.g. two-, six- and twelve-minute walk
tests), the literatwe was reviewed to determine which measwe would be best suited to the
current study. In the next section, waik test measures of functional exercise capacity for
individuals with cardiorespiratory disease are reviewed and the rationale for the selected
measure is provided.
1.4 Walk Test Measures of Functional Exercise Ca~acity in lndividuals with -
Cardiores~iratorv Disease
1.4.1 Definition
Functional walk tests are exercise tests that measure functional capacity; mainly, the
ability to undertake physically demanding activities of daily living (Guyatt et al., 1985a).
They are considered objective measures that provide a means of monitoring response to
treatment and to establishing pmgnosis (Singh et al., 1992). Compared to traditional
laboratory indices of exercise capacity such as cycle, treadmill and step ergometry, walk tests
require less technical expertise and equipment, making them inexpensive and easy to
adrninister (Mungall & Hainsworth, 1979). More importantly, they employ an activity that
individuals perform on a daily basis, i.e. waiking (Singh et al., 1992).
A variety of waik tests exist including fixed distance tests (e.g. one hundred metre
[Monce & Srnithies, 1984]), velocity determined waik tests (e.g. self-paced walk test [Bassey
et al., 1976]), tirne-based walk tests and shuttle walk tests (e.g. incremental shuale walk test
[Singh et al., 19921. Tirne-based walk tests and the increniental shunle walk test are
commonly used to assess functional exercise capacity in individuals with COPD (Brooks et
al., 1999; Singh et al., 1992). However, because the incrernental shuttle walk test requires
patients to walk at increasing speeds up and down a ten-meter course (Singh et al., 1992), we
did not consider this test feasible to administer with a rollator. Therefore, the following
review of the Iiterature will focus on time-based fiuictional walk tests.
Time-based walk tests include the two-minute walk test, six-minute walk test and
twelve-minute walk test. McGavin and colleagues fint used the twelve-minute walk test in
1 976. These researchen modified Cooper's (1 968) run test to an indoor twelve-minute waik
format for the assessrnent of exercise tolerance in those with chronic bronchitis. Butland and
colleagues (1982) later explored shorter venions of this test (Le. two minutes and six
minutes) in similar populations. These time-based walk tests are ideally conducted in an
enclosed quiet comdor. Individuals are instnicted to walk fiom end to end, covering as
much ground as possible in the allotted time period. Distance walked in the specified tirne
period is recorded.
1.4.2 Two-Minute Walk Test
The two-minute walk test has been studied in individuals with COPD, congestive
heart failure, children with cystic fibrosis (CF) and the frai1 elderly. Table 2 summarizes
these studies with respect to patient population and results of psychometric testing. In the
assessrnent of studies, interpretation of the strength of correlations was based on a grading
scheme used by Lacasse and colleagues (1997b, 1997~). Specifically, coefficients of
correlations ranging from O to 0.20 were considered negligible; 0.21-0.35, weak; 0.36-0.50,
moderate; and greater than 0.50, strong. This grading scheme was utilized as it has been
previously published and used in similar reviews (Lacasse et al., 199%; Lacasse et al.,
1 997c).
Two studies validated the two-minute walk test as a similar measure of exercise
tolerance as the six-minute waIk test and twelve-minute walk test in individuals with chronic
respiratory disease (Butland et al., 1982; Bernstein et al., 1994). Both Butland and
colleagues (1 982) and Bernstein and colleagues (1 994) found strong correlations with
distance walked in the respective time intervals (i.e. two minutes and six minutes).
Furthemore, Bernstein and colleagues (1994) demonstrated that two-minute walk test
distance was moderately to strongly associated with rneasures of oxygen consurnption (i.e.
some correIations were strong while others were of moderate strength).
One study specifically investigated the effect of encouragement and time of testing on
the reliability of the two-minute walk test (Guyatt et al., 1984). In addition to establishing
the presence of a learning/training effect with repeated testing, Guyatt and colleagues (1984)
found that encouragement improved distance waked while the time of day of testing had no
effect.
ûnIy one study assessed measurement properties of the two-minute walk test in each
of the pediatric and elderly populations. Upton and colleagues (1988) evaluated the two-
minute walk test as a measure of exercise tolerance in children with CF. They found the test
to be reliable by showing no significant difference in distance walked on repeated testing (Le.
two tests). They also determined that the distance walked was more responsive to treatment
than peak expiratory flow rate in those with near normal respiratory function. In the frai1
elderly, Connelly and colleagues (1996) reported the intra- and inter-rater reliability of the
two-minute walk test to be good to high.
Table 2: Studie Sîudy
Butland et aL (1 982)
Bernstein ez aL (1 994)
Popuiation adults with a varicty of respiratory diseases; predominately chronic airtlow limitation adults with chronic airflow limitation or chronic hem failure or both
chtldren with cystic fibrosis
elderly males with COPD
fiail elderly
VaIiditv: distance walkd correlates strongly with 6MWT (r=0.89) and
I Z M W (r=0.96) distances
Reliabilitv: - trend obsenw.i that simple encouragement irnprovcd distance walked (NS)
time of day of testing had no effect on distance walkcd - within subject vanabilit-y similar with and without encouragement -distance wilked improv&I on fim 2 walks cornparcd to lasi4 (pd.000 1 ) Res~onsfveness: -1es.s rcsponsive (0.90) than 6MWT (0.74) w.r.t ratio of within person standard deviation to ncaunent effect Reliabilitv:
no significmt difference on repeated testing; mean coefficient of variation 2.6% R e ~ ~ ~ n ~ i ~ e n e î s : -more responsive io in-patient treatment than PEFR Validitv: - using nvo minute intervals of the 1 ZM WT, distance walkcd in nvo minutes correlated mongly with distance walked in 6 ( ~ 0 . 9 5 ) and 12 minutes ( ~ û . 9 4 )
distance walked correlated strongly with V02/kg (r=O.55); moderately with V O r m (r=0.45) and negligibly with spiromeûic values (r-0.W. 13) Res~onsivencss: -change in distance walked strongly correlated with changes in VO& (r4.53) and V O z m 1s.53)
-
Reliabilitv: - inter-rater, ICC: 0.93-0.95 -intra-rater. ICC: 0.82-0.89
6MWT 6-mïnutc wlk test; lZMWT 12-minute wakk test; COPD chronic obsüuctivt pulrnonary discase; ICC intraclas conrl~tion coetficicnt; NS not significan~ PEFR p d c expintory flow ntc; VO* oxygcn consumption; VO~max r r n x i d oxygm consuniption; w.r.1 with mspcct to
1.4.3 Six-Minute Walk Test
The six-minute walk test has been studied arnong several different populations
including individuals with COPD, individuals with heart failure, individuals with
pacemakers, individuals with penpheral arterial disease, surgical patients and pediatric
patients. Tables 3-5 summarize these studies with respect to patient population and results of
psychometric testing. The majority of studies have focused on validating the test by
correlating distance walked to several other reference critena.
In individuals with COPD, several studies have examined validity of the six-minute
walk test by correlating distance waked to maximal oxygen consumption (V02ma.u),
pulmonary function tests (PFT), and rneasures of function and dyspnea. Distance walked has
been found to strongly correlate with V02rnax and workload maximum measured during
cycle ergometry (Bernstein et al., 1994; Wijkstra et al., 1994; Guyatt et al., 1985a; Guyatt et
al., 1985b;) and to moderately to strongly correlate with measures of fùnction (Guyatt et al.,
1985a; Guyatt et al., 1985b). Correlation with spirometry lacks agreement with some studies
finding strong relationships (Wijkstra et al., 1994; Mak et al. 1993) and others weak
(Bernstein et al., 1994). Correlation to measures of dyspnea have not yielded consistent
results (Wijkstra et al., 1994; Mak et al. 1993; Guyatt et al., 1985a; Guyatt et al., 1985b) and
correlation with the Chronic Respiratory Disease Questionnaire (CRQ) has been reported to
be weak (Wijkstra et al., 1994).
In individuals with heart failure, strong correlations between six-minute walk test
distance and VOzmax were observed by severai researchen (Roul et al., 1998; Cahalin et al.,
1996; Riley et al., 1992; Lipkin et al., 1986; Guyatt et al., 1985a; Guyatt et al., 1985b) and
moderate to strong associations with the New York Heart Association m] functional
classifications, oxygen cost diagram, Specific Activity Scale, Chronic Heart Failure
Questionnaire and the Rand instrument (O'Keeffe et al., 1998; Guyatt et al., 1 %sa; Guyatt et
al., 1985b). Furthemore, several studies have shown that six-minute walk test distance c m
discriminate between NYHA classification levels (Peeten & Mets, 1996; Riley et al., 1992;
Lipkin et al., 1986). Results of other studies in the same population have shown that distance
walked on the six-minute walk test [5300 meters] c m identiQ those with increased
likelihood of death or hospitalization within a time-frame ranging from three months to one
year (Milligan et al., 1997; Cahalin et al., 1996; Bittner et al., 1993). One study found no
prognostic value for survival of the six-minute walk test in individuals with advanced heart
failure (Lucas et al. 1999).
In individuals with pacemakers, distance waked has been determined to be
significantly related to oxygen cost, as measured by oxygen cost diagrams (Rozkovec et al.,
1 W ) , and exercise ergometry performance (Langenfeld et al., 1990). Other investigations
have shown that distance walked in six minutes is able to discriminate between pace modes
(Le. fixed rate or optimal response) and rates (Provenier & Jordaens, 1994; Rozkovec et al.,
1989).
In the context of pre-operative assessment, Holden and colleagues (1992) and
Szekely and colleagues (1997) showed that distance walked was predictive in regards to the
probability of successful surgical outcornes in patients undergoing pulmonary resection and
volume reduction surgery respectively. Another study (Kadikar et al., 1997) determined that
distances walked of less than 400 and 300 meters were usehl indicators of when to list and
prioritize patients for lung transplantation respectively.
Studies of reliability have concentrated on three main areas; specifically, the effect of
encouragement (in individuals with chronic heari and lung disease), senal testing (in
individuals with chronic lung disease, heart failure, pacemakers and peripheral artenal
occlusive disease) and time of testing (in individuals with chronic heart and lung disease).
Guyatt and colleagues (1984) found that while time of day of testing had no significant effect
on distance walked, differential encouragement produced variable results. Investigations of
repeated testing have s h o w generally comparable findings with total distance walked being
variable on the initial two walks and establishing consistency on the third (Guyaa et al.,
l985a; Guyatt et al., 198%; Guyatt et al., 1984; Langenfeld et al., 1990; Riley et al., 1997).
One study was specifically devoted to interpretability of the six-minute walk test.
Redelmeier and colleagues (1997) evaluated individuals with COPD and established that a
minimal change in walking distance of fifty-four meters is clinically important in that it
translates into a noticeable change in functional statu. This information is usefil for
examining the results of clinical trials. For example, Redelmeier and colleagues (1997)
reviewed the literature on the use of walk tests for measuring the effectiveness of treatments
for patients with COPD and found that 68% of the studies finding statistically significant
results reported differences in six-minute walking distance that were less than 54 meten.
Similarly, a meta-analysis revealed that the best estimate of the effect of respiratory
rehabilitation for individuals with COPD on distance walked in six minutes was 56 meters,
just two meters greater than the minimal clinically important difference (Lacasse et al.,
1996). Additionaily, recently established normal values and reference equations for the six-
minute waik test will potentially allow clinicians to detemine percent predicted values
(Troosters et al., 1999; Enright & Sherrill, 1998).
Finally, studies of responsiveness have shown that improvement in six-minute walk
test distance is related to diminished breathlessness in pacemaker patients (Rozkovec et al.,
1989), improvement in quality of life for elderly patients with heart failure (O'Keeffe et al.,
1998) and that changes in distance walked correlate with changes in V02max in individuals
with COPD (Bernstein et al., 1994).
Table 3: Studies of Psychometric Properties of the Six-Minute Walk Test in Patients with Chronic Obstructive Pulmonary D
Sîudy Bntfand et a& (1 982)
Guyalt et aL (1 984)
Guyan et aL (1 985b)'
Guyan et a& f I 9850).
Mak et aL(1993)
Wjkstra et aL ( 1 994)
Bernstein a aL(1994)
Popuiation adults with stabIe chronic respiratory disability adults with chronic airflow limitation or chronic heart failure or both
adults with chronic hem failure or chronic lung discase
- -
dul t s with chronic hem failure or chronic lune disease
du l t s with COPD or severe asthma
adults with COPD
elderly males with moderate COPD
Validitv: distance walked correlated strongly with 1 2MWï (r=0.96) and îMWT (r=0.89)
ReliabiliW: simple encouragement improved distance waIked (mean 30.5m, pc0.02) tirne of day of testing had no effect on distance walked within subject variability similar with and without encouragement w.r.t. test-retest (first wo walks compareci to 1s t four), distance walked
improved (p<0.000 1 ) Res~onsiveness:
reported to be more responsive (0.74) than the ZMWT (0.90) w.r.t. ratio of within person SD to treatment effect Validitv:
distance walked strongly conelated with cycle ergorneter test results (r=0.58, p<0.001) and negatively and modentely correlated with funcrional status as determincd by NYHA criteria (r= -0.45, p=0.06) and the SAS (r= -0.47, p=0.001) Relhbilitv: distance walked plateaued dunng walks 3-6 (p<O.ûû 1) within person SD of subjcct's mean distance walked was ~ 6 %
Validitv: distance walked stmngly correlated with cycle crgomeny test results (r=0.58,
p<O.OOI ) and moderately to strong with four functional status questionnaires [Rand Instrument, BDI. Thc Oxygen Cost Diagnm and the SAS], (r=0.47-0.59, p<o.Oo 1 ) Relia biliw:
ICC: 0.9 1-0.92 within- person SD was 22.52m with a coefticient of variation of 0.05 for walks
3-6 (versus within-person SD 29.8. coefticient of variation 0.07 for al1 6 walks) Validitv:
distance walked significantly (p4.001) and strongly correlated with Dtco (r=0.68), PEF @=OS), FEV, (r=0.53); negatively and strongly correlated with breathlessness rating on the MRC scale (-0.52); modentely correlated with FVC (r=0.48); negatively and weakly correlated with pcrceived breathlessness as measured by VAS (r= -0.35) and RPE measured by the Borg scale (r= -0.30); and did not correlate with Sa02 Validitv:
dinance walked mongly correlatcd with Wmax as assesseci by bicycle ergornetry (r=0.8 1, p<O.Ot), spirometric vdues and MIP (r=0.50-0.58) and DLco (~0 .62 ) ; negatively and moderately correlated with dyspnca at rest measured by the Borg scale (r= 4.41, p<0.01); and negligibly -weakly (F-0.03 to -0.25) with quality of life as rneasured by the CRQ (Fatigue. Emotion and Mastery domains) Validitv:
distance walked strongly correlated to V02 (r=0.5 1 ) and VO&g ( ~ 0 . 6 7 ) as assesseci by bicycle ergometry and distance wdked in 2 minutes ( ~ 0 . 9 5 ) and 12 minutes (r=0.97) but negligibly to weakly correlated with spirometry values (r=O .OS-û.X) Res~onsiveness:
changes in distance walked stronply correlated to changes in VGrnax (r=0.64)
nued) Po~uhtion
elderiy subjects with COPD
volume reduction surgery patients secondary to severe COPD
Measurement Properties Validitv:
distance walked significantly and strongly conrlated with Guyatt dyspnea score ( ~ 0 . 6 5 ; m.01) ReIiabilitv:
mean distance difference on repeated tests = 0.65rn (p-0.94) coefficient of repeatability = 63.0
Validiîv: presperative distance walked weakly to rnoderately correlated with lcngth of
hospitalization (r=0.32-0.40, pcO.05) presperative distance walked of eûûm specific (U%, p<O.i)04) in death
adults with stable COPD
Validiîv: distance wa1ked strongly correlated with patients' rating of heir walking ability
relative to othcr patients (r=0.59,95%CI: 0.54-0.63) Intemretabilitv:
distance walked ne& to differ by 54m (95%C1:37-71m) for the average patient to stop rating thernselves as "about the same" and to start nting themselves as "a littlc bit better" or "a linle bit worsc" in rating their walking ability relative to
'dcnota mixed w . Dyspnca Index; CI confidcnc; i n m a l ; COPD chronic obsmictivc pulmonary dix=; CRQ h n i c Rcspintory Discase Qucstionnairt; h c o diffusion capacity of carbon rnonoxide; FEV, forced cxpinmry volume in 1 second; N C forccd vital capacity; [CC inaclass correlation cocfficicnt; rn mettr, MIP maximum inspintory pressure; MRC Medical Rescarch Council; NYiiA New York Heart Association: N S not signiticant; PEF peak cxpiratory flow; RPE rating of pcrccivcd cxtrtion; SaO? Ytnal oxygm saturation; SAS Spccific Activity Scale; S D scandard deviation; VAS viswl analogue scalc; V O z m maximal oxygm consumption; W m u rnamul work capacity; w.r . t *ith respect to
Table 4: Stuc Siudy
Lipkin et aL (1 986)
Riley n aL(1992)
Cahalin et aL(1996)
Peeters and Mm (1 996)
Müiigan n aL(I997)
woo el aL(l997)
5 of Psychometric P Population
adu1t.s with stable chronic hem failure (NYHA CI= 11-111)
adults with chronic heart faiIure (NYHA class II-IV)
adults with CHF (SOLVD registry)
adults with chronic hem faihrc undergoing cardiac transplant evaluation
elderly subjects with chronic hem failure (NYHA class II-III)
phase I cardiac rehabilitation inpatients with leR ventricular dysfunction adults with advanced hem failure (NYHA class r r 1 4 v )
perties of the Six-Minute Wak Test in Patients with Heart Failure Mesisurement Properties
Validitv: distance waIked related t0V0~rna.x curvilinearIy (large variance in chose with
low versus high V02rnax) ail patients considerd walk test more representative of daily physical activity
than treadmill test able to distinguish b/w normals, NYHA class 11 and class I I I heart failure
patients ( ~ 0 . 0 0 3 ) based on distance walked Validitv:
distance walkeâ smngly correlated with V02 max measured during treadmill ergometry (r=0.88, p<0.0001) and peak V02 measured during thc walk test (r=0.90; ~ 0 . 0 0 0 1 )
able to distinguish b/w NYHA class II, I I I & IV patients based on distance waIked Reliabilitv:
distance walked increased from test 1 to test 2, but no significant difference was seen from test 2 to test 3 ValidiW:
patients in the lowest performance levels (distance walked <300m) had a significantly greater chance of dying (10.23% vs. 2.99%, p=O.O 1 ), of being hospitalized in general (40.91% vs. 19.90%. p=0.002) and of being hospitalized for hem failure (22.16% vs. 1.99OA. pO.001 ) within subsequent year
compared with those who walked at least 450rn, patients who walkcd less than 300m had a 3.7- fold risk of dying (95OhCI: 1.34-9.33) and those who walked between 300-3749m had a 1.78-fold risk (9S%CI: 1 .O!?-7.1 1 ) within subsequent Yeu Intemretabilitv: each dccrement in distance walkcd of IZOrn rcsultcd in a 160% increase in
hospitalization for CHF during the one year follow-up pcriod
Validitv: distance walked smngly correlated with VO?mau (r=0.64, i=0.41. p O . O O O 1 ) in a multivariatc analysis of patient chancteristics, resting hemodynamics and
6MWT distance, distance walked was the strongest predictor of VQmax distance walkeâ c300rn prcdictcd an increased likelihood of death or pre-
transplant hospital admission within 6 months (40% vs. 12%. p=0.04) but did not predict long term overall or event-free survival Reliabilitv:
ICC:O.96 Validitv:
significant difference in distance walked between NYHA class 11 and I I I patients and between controls and between contruls and class III patients (p<O.OO 1 ); difference betwecn controls and class II patients NS Validity:
patients who survived greater than 3 months walked significantly further than those who survived less than 3 montfis (3.56 vs. 2.35, p=û.003) according to the following scale: l =non-ambulatory; 2= 10-1 00 ft; 3= 10 1 -500 ft; 4=50 1 - 1000 ft; 5=1001-2000 ff +2000 + ft Validitv:
distance walked not significantly associated with hem rate variabiIity (non- invasive masure of autonomic tone)
distance walked related (value not given) to I year rnonality ( ~ 0 . 0 3 ) but not to risk of sudden de&
ued) Popuiation
adults with hem failure
frail e[derly subjects with h e m failure
adults with chronic congestive heart failure adults with advanced hem failure
distance walked snongly correlated to VO,max in patients who walked less than 300m (r-0.65, h . 4 2 , p=O.O 1 )
no sîgnificant difference in distance walked between patients who died or were hospitalized for heart faiIure and thosc who s u ~ i v e d event-free - using ROC curves and survival curve analysis, subjects walking less than 300m tendcd to have wone outcomes Reliabilitv:
ICC:0.82 Validitv:
mong bascline correlation between distanceci waiked and total CHQ score: F - 0.79; with dyspnea dimension of CHQ: r= -0.58 ReliabilItv: [CC = 0.91
Res~onsiveness: responsiveness coefficient 1.73 effect size for detecting subjective heart failure deterioration (2.13) greater than
for detecting improvement (0.85) change in distance walked strongf y correlated with change in total CHQ score
(r=0.70), dyspnea dimension (r=0.60), fatigue dimension (r=0.58) and global nting of change (r=0.78); modentcly correlated with cmotion dimension of CHQ (r=0.47) Reliabilitv:
results (ie. distance walked) of tests performed the same day 30 minutcs rtpart are quivalent to results of tests performed on t consccutive days Vat iditv:
monç correlatian (r=0.57) with peak V 0 2 whcn al1 subjects includcd; wcak correlation ( d . 2 8 ) when only subjects with peak V 0 2 between 10-20 mLkg pcr minute includd
6MWT distance did not predict survival congestive
-
-
Table 4 (contin Study
Roui et all (1 998)
O ' Keefle a aL, (1 998)
Oposich a aL (1 998)
hem
m
-
--
-
tt fcct; CHQ
Lucas et a&, ,1999)
:
bMWT 6-minute Chmnic I
wdk test; biw betwm; C ICC correlation çoctlïcicnt; m meters; NYHA New York Hcart Association; NS not stgnificuit; Studies of Leil Vcnmcular Dysfunction; V02m;i.t miml oxygcn consumption
ROC SOLVD
Table Study
adults with pacemakers
Langen fefd et aL (1 990)
adults with pacemakers
Provenier & Jordaens (1 994)
adults with pacemakers
Cahaiin et aL (1 995)
adults with end- stage lung disease (msplant candidates)
Kadikar et oL(1997)
Niron et al. (1 996)
adults with end- stage lung disease
children with end- stage cardiac or pulmonary diserise (awaiting
Holden et aL(1992)
~Montgorncry & Gardner (1 998)
Harada a al,( 1999)
transplantation) pulmonary rcsection patients secondary to bronchogenic carcinoma
adults with intermittent claudication secondary to peripheral artenal disease older adults
:ric Properties of the Sir-Minute Walk Test Measurement Prmerties
Validitv: distance walked directly related to con (ie. as per O2 diagram) ( ~ 0 . 0 5 ) significant difference in distance walked b/w pacing rates (50, 70 and 90 bpm)
Res~ansiveaess: improvement in breathlessness over preceding 2 weeks signif~cantiy
associated with an increase in waIking distance Validitv:
distance walked strongly correlated with cycle ergorneuy ( ~ 0 . 7 4 ) al1 patients stated walk test replicated daily physical activity more accuntely thm
cycle ergornetry ReIiabiIitv:
no simificant difference in distance walked found between reucated walks Validitv:
distance walked significantly greater in the W I R set pacemaker than in the f ~ ~ t d VVI) of 60bpm (21.91~1; 9596CI: 3.540.3m) and in WI 85 than in WI 60 ( 14.71~1; 95%CI 0.6-28.9m) Validitv:
distance walked strong predictor of V02max (r=0.73. ?=0.54, p<O.OOOI) no significant diffcrence found betwetn esrimateci and observed V0,rna~ using
prediction equation based on 6M WT distance Reliabilitv:
ICC reportai to be 0.99; however, no indication was given in methods that reliability was tested. Validitv:
findings suggestive of predictive validity distance walked 400m prcdictive of dcath with scnsitivity: 0.80. specrficity:
0.49, PPV: 0.27 and NPV: 0.9 1 distance walked<3ûûm prcdictive of death with sensitivity: 0.52, specificity:
0.80, PPV : 0.38 and NPV: 0.88 Validitv:
distance walked corrclated with V02mac ( d . 7 0 , pc0.05) and physical work capacity (r=0.64, pe0.05) but was not significmtly related to indexes of pulmonrüy function ( r d . 15-0.26)
Validitv: those who had successful surgical outcomes walked further than those who died
within 90 days of surgery distances of greater than IO00 feet predicttve of successful surgical outcorne
(long-term survival greater han 90 days) [sensitivity: 100%; PPV: 85%; NNV:
distance wdked strongly correlated with the AnkIeBrachial Index (r=0.55, p<O.OO i ) and modentely conelated with V02max ( ~ 0 . 3 7 , p=O.O 1 ) Reliabilitv:
[CC:0.94, coefficient of variation 10.4% for distance walked [CC: 0.90. coefficient of variation 1 1.7% for numbcr of seps
Validitv: distance walked significantly greater for active vs. inactive subjects ( ~ 0 . 0 0 0 1 ) distance walked correlated strongly with lower body strength (Le. chair stands)
[r=O.6fl, standing balance (r=0.52), self-reported physical functioning [SF-36 Health Survey] ( ~ 0 . 5 5 ) and gait speed (r4.73); moderately with general halth perceptions (r=0.39) and ncgligibly with body mass index ( ~ 0 . 0 7 ) . Reliabilitv:
one week test-retest reliability was 0.95 iL
6MWT 6-minute walk test; bpm k t s per minute; biw bctwcen; CI confidence NPV negahvc prcdictivc value; 0: oxygcn; PPV positive prcdictivc value; rrsponsc; VViR optimal rate rtsponsc
3
.,
-
9
m nrtcrs; fixed rate
1.4.4 Twelve-Miuute Walk Test
Adults with respiratory diseases were the only patient group with published Iiterature
on the twelve-minute walk test. Studies examining the psychometric properties of the
twelve-minute walk test are summarized in table 6.
Several studies have correlated distance walked in twelve minutes with measures of
functional status and VOzmax or workload maximum with generally consistent findings. For
instance, several investigators (Larson et al., 19%; O'Reilly et al., 1982; McGavin et al.,
1978) have found moderate to strong correlations with subjective assessments of function,
while othen (Bernstein et al., 1994; Swinbum et al., 1985; Alison & Anderson, 1981;
McGavin et al., 1976) have found strong correlations with measurements (Le. VOz mau and
workload maximum) taken during exercise ergometry. As noted for the six-minute walk test,
studies evaluating the relationship between distance walked in twelve minutes and measures
of pulmonary function have produced variable results. For exarnple, correlations between
twelve-minute walk test distance and FEVl have ranged fiom not significant (Mungall &
Hainsworth, 1979; McGavin et al., 1 W6), to negligible (Gerardi et al., 1996; Swinbum et al.,
1985; O'Reilly et al., 1982), to moderate (Larson et al., 1996; McGavin et al., 1978), to
strong (Dekhuyzen et al., 1986; Alison & Anderson, 1981). One study (Gerardi et al., 1996)
found that twelve-minute walk test performance (i.e. distance walked) after out-patient
pulmonary rehabilitation was the most influential predictor of mortality for individuals with
severe COPD when compared to FEV,, arterial blood gases, weight, quality of life scores,
CO-morbidity and oxygen and medication requirements.
The only study to evaluate the twelve-minute walk test in the context of pre-operative
assesment was by Bagg (1984). The results of this investigation suggested that the test was
not discriminative in regards to the risk of occurrence of post-operative complications in
individuals undergoing pulrnonary resection.
Studies of reliability have s h o w generally similar findings with distance walked
being variable on the initial two walks and establishing consistency on the third (Lanon et
al., 1996; Swinbum et al., 1985; Mungall & Hainsworth, 1979; McGavin et al., 1976).
Studies of responsiveness have found the twelve-minute walk test to be sensitive to
changes in exercise capacity (Bernstein et al., 1994; Cockcroft et al., 1981) and to strongiy
correlate with changes in assessments of breathlessness (O'Reilly et al., 1982) but that
changes in distance walked were not related to long-term survival in individuals with COPD
(Gerardi et al., 1996).
Rlison & Anderson (1 98 1)
Swinburn et aL(1985)
male adults with chronic bronchitis
adults with respiratory disease (airway obstruction or infiltrative diseases ) adult males with chronic bronchitis
d u i t males with COPD
adults with COPD
adult males with COPD
adults with chronic respiratory disability lung resection patients second- to carcinoma of the bronchus
adults with severe COPD
! f ies of the Twelve Minute Walk Test Merisurement Pro~erües
distance walked significantly correlated with VOlrnax (r=O.jt. p<0.01), VE (r=0.53, p<O.O 1, FVC (r=O.4 1, ~ 0 . 0 5 ) ; NS with FEV, (r=0.28, p>0.05) Reliabilitv:
reported to be reliable if pcrformed twice; howcver, data used to support this . .
conclusion is not clearly pksented Validitv:
distance walked significantly ( ~ 0 . 0 1) and strongly correlated with FVC (r=0.52-0.64), oxygen-cost diûgram (r=0.60-0.68) and RPE (r= -0.39 to -0.74) in both diseases; strongly correlated with DLc0 (r=0.63) and modentely correlated with FEV, (~0.44) in those with infiltrative disease
Validitv: distance walked mongly correlated with DLco (r=0.67; p<O.OI); invenely and
strongly correlated with ventilatory response to an increase in oxygen uptake (r=0.77; ~ ~ 0 . 0 1 ) ; NS with FVC, FEV, or TLC Relinbilitv:
distance walked on test 3 significantly ( ~ 0 . 0 5 ) bener than on tests 1 and 3; no signifiant change aAer test 3
coefficient of variation +4Z% aAcr test 3 Res~onsiveness:
the most sensitive index of change in functional exercise tolerance aAer rchabili cation whcn cornpareci to spiromecry. treadmill ergomctry and subjective interviews
distance walked strongly correlated with Wma. (r=0.68, p-4.001). FEV, ( ~ û . 6 2 , p<0.001) and VC (r=0.65, p<O.OOI)
VOzmax mcasured during IZMWT did not differ significantly from V02max measured on the bicycle erpomcter Validitv:
distance walked modentely-strongly correlated with asscssrnents of breathlessness (~0.50-0.70, pcO.001); but did not correlate with spimmetry Reliability:
mean variation of 3.1 % when perforrned twicc on same day; 9.1 % when performed 2 weeks apan Res~onsiven ess:
changes in distance walked strongly correlated with changes in assessmcnts of breathlessness (~0.64-0.90) and with DLc0 (~0.68, pcO.05) Validitv:
Iargest variance (29.6 m) when compared to the 2iMW (23.4 rn) and 6MWT (26.0 m) distances Validitv:
no significant difkence ( ~ 0 . 0 5 ) in distance walked benveen patients who did and did not suffer pst-operative complications
while PFT provided significant separation b/w groups, no further discriminating power was abserveci with distance walked Validitv:
!inance waiked strongly correlateci aith p e r f o m c e on cycle ergometry (r=Q.S 1, ~ 0 . 0 1 ) a@ nep ergometry (?=OS?. pc0.0 1 ) but not with FEV, (?=O. 13) or W C (-0.1 7) Reiiabilitv:
significant (peO.0 1 ) increase in distance walked biw tests I & 4; however, incrernents blw successive attempts tended ta decrease
Table 6 (continu Study
Dekhuyzcn et aL(l986).
Bernstein eî aL(1994)
Gerardi et a l (1 996)
Population out-patient adults with COPD
elderly mdes with modente COPD
predominantly (87%) adults with severe COPD
adults with moderate-severe COPD
Measurernent Pm perdes Validitv:
distance walked strongly conelated with FEVt [ml] (r=0.62; p=O.ûûI); moderately correlated with IVC [% predicted] ( ~ 0 . 4 9 , p=0.001), FEV, [% predicted] (r=0.49, pQ.00 1 ). PaOS (r=O.U, p=O.O 1); and weakly correlated with DLco (r=0.34. p=0.05) Validitv: + distance walked correlated strongly to VOTfkg ( ~ 0 . 6 5 ) and moderately to V0: (r0.49) as ysessed by bicycle ergohetry; cor&atd negligibly with spirometry values (r=O. 12-0.26)
distance walked stmngly correlated with that in 2 & 6 minutes (r=0.94-0.97) Res~onsiveness:
changes in V02max more closely related to changes in IZMWT distance (r=0.72) than to changes in shoner duntion walk test distances (r=0.53-0.63) Validitv:
pre-rehabilitation distance walked negligibly correlated with FEVl (r=O. 19; p=0.03) and weakiy correlatcd with total CRQ score ( ~ 0 . 2 3 ; p-0.0 1 )
post-outpatient pulmonary rehabilitation distance walked most significant variable related to prognosis compared to FEV,, ABG, weight, CRQ score, co- morbidity, oxygen requirements and medication requirements
patients with post rehabilitation distance walked ~750m had 68% 3- year survival; those with distances walked >750m had 92% 3-yeac survival Res~onsiveness:
17% change in distance walked between pre- and post-outpatient pu lmonq rehabilitation: however. change not relata to long term sukival
-
Validity: walk distance correlated strongly with MIP ( ~ 0 . 5 2 ) ; modentcly with FEV,
(% preâicted] ( ~ 0 . 4 0 ) ; rnodentely and ncgativcly with the total SIP (F -0.37). thc Physical Dimension of the SIP (r= -0.45), and exercisc related breathlessness as measured by ATS-DLD Breaihlessness Scale ( r= -0.49) Reliability:
distancc walkcd increascd over first 3 tests (pcO.01); tcst-retcst reliability:
.L ad
bl& prises; ATS-DL0 Arncncan Thoncic Society. Division of Lung Disases, COPD chmnic obstmctive pulrnonq diseasc; h c o diffusion capacity of carbon rnonoxidc; FEV, forceci expintory volume in I second; FVC forccd vital capacity; [VC inspintory vital capacity; rn rncters; MIP mximurn expintory pressure; NS not significant; PaO? partial prrssurc of arvnal oxygcn; PFT pulmonary function testing; RPE nting of perccivcd excruon; SIP Sickness Impact Profile; TLC total lung capacity; VE; minute vcntilauon; V 0 2 oxygcn consumption;V02m;t m t m l oxygcn consumption; Wrmx maximal work capacity
1 r0.98 for tests 3 8r 4 1 mill; ?MW' 2-minuu walk tesc 6MWT 6-minute walk test; I2MWT 12- rninutc walk tesf b/w bcwcen; ABG arrend
1.4.5 Factors Affecting Performance
Several variables have been identified in the literature as potentially influencing
distance walked during a time-based walk test. Fint, the use of differential encouragement
can affect test results and therefore necessitates that the use of encouragement with walk test
administration be standardized with respect to type and timing (Guyatt et al., 1984). in the
studies reviewed, standardized encouragement consisted of specific statements given by the
test adrninistrator (e.g. "keep up the good work" and "you're doing well") every 30 to 60
seconds (Guyaa et al., 1984). The magnitude of the effect of encouragement on distance
walked found by Guyatt and colleagues (1984) [Le. 30.5 meten] was similar to that reported
in studies claiming to show beneficial effects of treatment interventions (Guyatt et al., 1984)
and approached the minimal clinically important difference f o n d for the six-minute walk
test by Redeimeier and colleagues (1997). Second, training and leaming effects with
repeated testing have been identified in several studies (Lanon et al., 1996; Riley et al.,
1992; Sin& et al., 1992; Upton et al., 1988; Guyatt et al., 1985a; Guyatt et al., 1985b;
Swinbum et al., 1985; Guyatt et al., 1984; Butland et al, 1982; Mungall & Hainsworth, 1979;
McGavin et al., 1976). For instance, one study (Guyatt et al., l985b) showed that six-minute
walk test distance could improve sixty meters afier three repeated six-minute walk tests in
individuals with COPD. These effects potentially could be misinterpreted as a positive
treatment effect or improvement in fûnctional statu, thereby illustrating the necessity of two
practice walks before performance is measured (Bittner, 1997). Third, placement of the
tester during the walk test (Le. standing still, walking behind patient, or waiking beside
patient) may affect performance. Although no study was located that investigated this factor
(Le. pacing), it would seem appropriate that the tester either stand still at one end of the
comdor or walk behind the patient to avoid pacing. Finally, numerous studies have
recognized that patients' feelings and mood c m affect performance (Bernstein et al., 1994;
Mak et al, 1993; Knox et al., 1988; McGavin et al, 1976).
1 A.6 Summary
The measurement of functional exercise capacity has become an integral component
of evaluating the impact of an intervention and detemining prognosis in those with
cardiorespiratory disease. The two-, six-, and twelve-minute walk tests are cornmonly used
for the measurement of functional exercise capacity in these individuals. Table 7
summarizes the evidence for the psychometric properties of two-, six- and twelve-minute
walk tests.
Table 7: Summary of the Evidence for the Psychometric Properties of the Two-, Six- and Twelve-Minute Walk Tests
Items in prcntheses denotes population in which psychomctnc pmperty was cxamined; + dcnotcs cvidcncc to support; - denotes cvidmce to rcfutc; O denotes no cvidencc; CHF congestive hem failurc; CF cystic tibmsis; COPD chmnic obsmctive pulmonary disase' ESLD end swgc lung discase; PAD penpheral artcrial discase
In addition to considering the psychometric properties of these tests, thought must
also be given to feasibility, ease of administration and patient tolerance when recommending
a specific test for clinical or research purposes. When comparing timed-based walk tests, the
six-minute walk test presents with a number of advantages. The six-minute walk test is
better tolerated by individuals with respiratory disease than the twelve-minute walk test
(Butland et al., 1982). It is also more reliable and responsive than the two-minute walk test
(Guyatt et al., 1984) and more reflective of the requirements of activities of daily living.
Given these advantages and supported measurement properties for individuals with COPD,
the six-minute walk test was chosen for the current study.
1.5 Research Questions and Hv~otheses -
Rollators are ofien prescribed for individuals with COPD in an effort to improve their
hnctional exercise capacity and quality of life. The Assistive Devices Pmgrarn of the
Ontario Ministry of Health provides financial assistance for the purchase of equipment
essential for mobility and independent living and currently fùnds up to seventy-five percent
of the cost of these rollators; the remainder being funded by the patient. Given the costs to
the patient and the health care system, it is important that the more widespread usage of
rollaton be preceded by evidence of their effectiveness. The current evidence does not allow
us to adequately determine the effect of a rollator on bct ional exercise capacity in
individuals with COPD, nor does it allow us to predict which individuals with COPD will
benefit most frorn using a rollator. Finally, the available literahire does not provide
significant insight into the specific mechanisms that may be responsible for change in
hctional exercise capacity with use of a rollator. As such, this study was conducted to
answer the following research questions:
1) What is the short-term eflect of a rollator on funciional pxercise capacity in individuals with CWD?
2) Which individuals with COPD will benefii most from using a rollator?
3) What are the underlying mechanisms that may contribute to change in funetional mercise capacity with use of a rollator?
The research hypotheses for this study are:
1) The use of a rollator improves functional erercise capaciy in individ~ials with COPD us determined by an improvement in distance walked andor a reduction in dvspnea during the si.-minute walk test.
2) Individuals who are most disabled (based on distance walked) will benefit most fronr using a rollator.
3) Change in breathing pattern is the mechanism responsible for improvenlent in funciional exercise capacip with use of a rollator. ntere will be no ussociated change in gait variables.
Chapter 2: Methods
2.1 Subiects -
2.1.1 Sampling and Recruitment
A sample size estimation using a two-tailed test with a type 1 emor of 0.05 and power
of 90% determined that a clinically significant difference in six-minute waik test distance
(i.e. 54 meters, Redeheier et al., 1997) would be detected with a minimum of 16 subjects.
This sample size calculation assurned a standard deviation of 86 meten based on variability
observed in previous studies fiom West Park Hospital (Goldstein et al., 1994). However, to
allow for the potential of using multiple linear regression with at least three variables, a
sample size of 40 was sought. This estimation was based on the method described by
Norman and Streiner (1999) who recomrnended that the sample size be 5 to 10 times the
number of variables included in the regression equation.
Subjects were recruited from the respiratory rehabilitation prograrns (Le. in-patient
and out-patient) at West Park Hospital (Toronto, Ontario, Canada). Subject recruitment
occurred between October 1999 and Iuly 2000.
2.1.2 Inclusion and Exclusion Criteria
Subjects were considered eligible for the study if they had a medical diagnosis of
COPD, were between 55 and 85 years of age and were unaccustorned to the use of a rollator.
Furthemore, they had to be clinically stable with no evidence of acute exacerbation.
Exclusion criteria included the presence of CO-existing conditions that may have limited
exercise tolerance or ambulation (eg. angina, uncontrolled cardiovascular disease,
musculoskeletal problems). Subjects who were not able to communicate in English or who
were unable to waik unaided were also excluded. Subjects who were partaking in a post-
operative respiratory rehabilitation program (Le. post lung volume reduction surgery,
bullectomy or transplant) were not considered eligible for the study. A screening form was
used to determine eligibility (Appendix 1).
2.2 Studv Desim -
2.2.1 Protocol
Al1 research procedures were approved by the Human Subjects Review Committee at
the University of Toronto (protocol #3289) and the Clinical Evaluation and Research Unit
and the Medical Quality Improvement Committee (Research) at West Park Hospital. The
study was hlly explained to subjects and written informed consent was obtained fiom al1
subjects (Appendix 2).
A randomized cross-over design, using the six-minute walk test as the primary
outcome measure, was used for this study. The six-minute walk tests were camed out as in
Honeyrnan and colleagues (1996). Each subject was studied at the same time of day on two
separate days in the same calendar week. On each study day, two six-minute wak tests were
performed with a minimum of a one-hour rest in between. One walk test was performed
unaided and the other done using a rollator (Opal Legacy, Therapist's Choice Medical
Supplies, Toronto, Ontario) with the order of the test randomized, using a random number
table, on the first day and reversed on the second day.
The study was conducted over 60 meters of a 3.4 meter wide enclosed comdor at
West Park Hospital. Pylons were placed at either end of the course. We chose the longest and
widest course available to minimize the effects of tuming. Every attempt was made to
perform testing under quiet conditions with a minimum of distractions and comdor traffic.
Al1 subjects perfonned at least two practice walks before data collection in order to control
for learning and practice effects (Bittner, 1997). Standardized instructions were provided to
subjects and no encouragement was offered during the tests. Subjects were insmicted to: 1)
walk From end to end, covering as much ground as possible during the test period; 2) stop
only if they felt too fatigued or breathless to continue; 3) decide, afier stopping, when to
resume walking; and 4) not speak while walking. The tester walked behind the subject in
order to avoid pacing. When the six minutes had elapsed, the subjects were told to stop.
The same rollator was used for al1 subjects, with the height standardized by ensuring
that the handle bars of the rollator were at the level of the subject's ulnar styloid process
(Pierson, 1994). The measured height was kept consistent for both test days.
During each walk test we measured distance walked and perception of dyspnea,
cardiorespiratory variables, gait variables and the arnount of upper extremity weight-bearing
when using the rollator. Pior to each test, we calibrated the respiratory inductance
plethysmograph (Respitrace, Ambulatory Monitoring, Inc., Ardsley, New York) against a
volume spirometer (Morgan Spiroflow, P.K. Morgan Ltd., Rainham, Gillingham). At
completion of the study, subjects were asked to complete a standardized questionnaire to
assess whether they preferred w a h g with or without the rollator (Appendix 8).
The tester used a trolley to cary the monitoring and acquisition equipment (Figure 1).
For subjects using supplemental oxygen, the portable oxygen canister was also c h e d on the
tester's trolley for each walk test.
Bronchodilator use was standardized by having subjects use their inhaled
bronchodilators thirty minutes before starting each session. CafFeine was withheld for at
least four hours before the study and subjects were instnicted to Wear the sarne footwear on
both study days.
2.2.2 Data Acquisition
The monitoring devices and acquisition equipment were portable and received power
From a 12-volt rechargeable battery. Signals fiom the respitrace inductive plethysmograph,
Morgan Spiroflow, distance sensor, pulse oxirneter, upper extremity weight-bearing sensing
mechanism and stride counter were sampled at 100 Hz using a laptop cornputer (Toshiba
Satellite Pro 410CS) with a data acquisition card (DAQCard-Ai-16X.E-50, National
Instruments, Austin, Texas) and LabVIEW data acquisition and processing software (V5.1,
National Instruments, Austin, Texas). In consultation with a data acquisition engineer From
National Instruments, we adapted a vimial instrument (VI) fiom the LabVIEW library for
data acquisition. A VI is a program in the graphical programrning language G that models
the appearance and huiction of a physical instrument (National Instruments, 1999). The
channels used for data acquisition are depicted in table 8.
Figure 1: Photograph of tester's trolley set up with monitoring and acquisition equipment.
Table 8: Data Acquisition Channels
Channel Input
Rib Cage Belt of Respitrace Inductive
Plethysmograph
Abdomen Belt of Respitrace Inductive
Plethysmograph
Oxygen Saturation
Heart-Rate
Distance Sensor
Stride Counter
Upper Extremity Weight-Bearing Sensing
Mechanisrn of RolIator
Morgan Spiroflow (calibration prior to 6-minute walk
test)
The data acquisition card was attached to a shielded connector box (SCB-68, National
Instruments, Austin, Texas) using a one meter 68 pin cable (PSHR68-68, National
Instruments, Austin, Texas). The cornputer, comecting cable and connector box were
secured and carried on the tester's trolley (Figure 1).
2.2.3 Measures
The measures used for this study are categonzed in table 9 and are described in detail
in the following text.
Table 9: CIassification of LMeasures Prima i
Six-Minute Walk Test Distance (and rests) *
Modified Borg Rating
CRQ - Chronic Respintory Dis1
Secondarv
Cardiorespiratory Firnction VentiIatory Variables + Oxygen Saturation + Hem-Rate +
Gait Stride Length + Walhng Speed + Modified Borg Rating of Leg Discornfort +
P - -
esse Questionnaire; SGRQ - St. George' corresponds prirn&ly to research question I i corresponds prirnuil; to resevch 2 - corresponds primariiy to rcsearch question 3
Demographic Data #
Health-Related Quality of Life (CRQ and SGRQ) #
Upper Extremity Weight-Bearing +
Preference +
--
Respintory Questionnaire
2.2.3.1 Primary Measures
Functional exercise capacity was the primary outcome of this study and was
evaluated by the following two measures.
2.2.3.la Six-Minute Walk Test Distance
A photosensing device (Photoelectric Switch, Omron Corporation, Tokyo,
Japan) was placed on the wheel of the tester's trolley and was used to collect automated
distance measurement via channel 4 of the data acquisition system (Table 8). Additionally,
the number and duration of rests taken during each six-minute walk test was manually
recorded on the data collection form (Appendix 3).
Validation of the photosensing device occurred prior to the commencement of
data collection by comparing the automated distance measurement to manual measurement
using a meter trundle. Validation was performed at differing waiking speeds ranging fiom
45 rneters per minute (m/min) to 105 m/min. The largest error observed was 0.3 meten
which is clinically insignificant.
2.2.3.1 b Modified Borg Rating of Dyspnea
The modified Borg scale is a comrnonly used tool to evaluate dyspnea during
exercise (Hamilton et al., 1996; Kearon et al., 1991). Consisting of numbers ranging From O
to 10 with descriptive phases anchored to specific numben, it is simple to use and easy for
subjects to understand (Hamilton et al., 1996; Kearon et al., 1991). A copy of the scale c m be
found in appendix 4. The modified Borg scale is a categorical scale; however, it has ratio
properties that allows mathematical manipulation of ratings and the use of parametnc
statistics (Kearon et al., 199 1; Borg, 1982; Borg, 1980).
At the start and completion of each six-minute walk test, subjects were asked
to rate their discomfort of breathing (i.e dyspnea) using the modified Borg scale (Hamilton et
al., 1996; Killian et al., 1992; Kearon et al., 1991; Borg, 1982). These values were
documented on the data collection form (Appendix 3).
2.2.3.2 Secondary Measures
2.2.3. t a Measures of Cardiorespiratory Function
2.2.3.2ai Ven tilatory Variables
Respiratory inductance plethysmography is a non-invasive respiratory
monitoring technique based on measurement of rib cage and abdominal motion during
breathing (Stromberg et al., 1993; Tobin et al., 1983; Cohn et al., 1982). Two cloth bands
composed of tenon-insulated wire coils are placed around an individual, encircling the rib
cage and abdomen (Stromberg et al., 1993). The Ieads From each coi1 connect to an
oscillator, which is connected to a demodulator (Stromberg et al., 1993; Tobin et al., 1983;
Sackner et ai., 1980). Movement of the chest and abdomen during respiration causes the
cross-sectional area bounded by each of the bands to change, which produces a proportional
change in the self-inductances of the coils (Hodsman et al., 1987; Tobin et al., 1983; Chadha
et al., 1982; Cohn et al., 1982). The changes in inductances are then converted into a
proportional voltage change by the oscillator (Hodsman et al., 1987; RespitraceTM Manual,
1979). Respiratory inductance plethysmography is comrnonly used to evaluate breathing
pattern and minute ventilation and has been validated in individuals with COPD (Tobin et al.,
1983) and during both treadmill and ergometer exercise (Wells et al., 1986; Sackner et al.,
1980).
We used a respiratory inductance plethysrnograph (Respitrace, Ambulatory
Monitoring, Inc., Ardsley, New York) to evaiuate 1) respiratory rate (Le. number of breaths
per minute), 2) the phase relationship of rib cage und abdominal rnovements (i.e. extent of
asynchronous or paradoxical breathing [Gosselink et ai., 1995; Tobin et al., 1 983]), 3) minute
volume (i.e. volume of air inspired over a minute period) and 4) relative conrribuiion of the
Nb cage and abdominal cornpartments to breathing.
The rib cage band was placed just under the axilla and the abdominal band
was placed below the lowest vertebral rib and just above the iliac crest (Verschakelen et al..
1989; Loveridge et al., 1983; Cohn et al., 1983). The bands were placed directly on the
subject's skin as recornmended by the manufacturer and were secured by surgical tape
(Millman et al., 1986). The electronic oscillator unit was then taped to the chest wall to
eliminate artifacts caused by movement of the unit (Cohn et al., 1982; Sackner et al., 1980).
The demodulator was positioned on the tester's trolley. Data were collected through
channels O and 1 of the data acquisition system (Table 8).
Considering that the respitrace inductive plethysmograph only measures cross
sectional volume under the coils of the bands (i.e. transducer), it is necessary to multiply each
volume (i.e. rib cage and abdomen) by some factor, which compensates for the volume not
rneasured by the transducer (RespitraceTM Manual, 1979). These calibration factors are
determined by c o m p ~ s o n of a volume standard and the respitrace inductive plethysrnograph
(RespitraceiM Manual) using accepted reference equations (Stradling et al., 1985; Chadha et
al., 1982; Cohn et al., 1982; RespitracetM Manual, 1979). These equations can be found in
Appendix 5. Volume measurements obtained with calibrated respiratory inductance
plethysmography have been found to be within ten percent of those denved f?om
simultaneous spirornetry. (Stradling et al., 1985; Tobin et al., 1983; Cohn et al., 1982;
Chadha et al., 1982)
For this study, calibration was accomplished using a Morgan Spiroflow (P.K.
Morgan Ltd., Rainham, Gillingham) volume spirometer. During calibration, subjects were
asked to stand and breathe through the Morgan Spiroflow for approximately fifteen to hventy
seconds while simultaneously being C O M ~ C ~ ~ to the respitrace inductive plethysmograph.
Calibration occurred immediately before each walk test. Data were collected through
channels O, 1 and 7 of the data acquisition system (Table 8).
2.2.3.2aii Oxygen Saturation and Heart-Rate
Oxygen saniration and heart-rate were acquired continuously with a pulse
oximeter (Ohmeda Biox 3700) through channels 2 and 3 of the data acquisition system
(Table 8). The same oximeter with a finger probe was used for al1 testing. The pulse
oximeter was carried on the tester's trolley. Validation of the linearity of voltage output from
the Ohmeda Biox 3700 pulse oximeter occurred prior to the commencement of data
collection by viewing both oxygen saturation and heart-rate signals on a digitizing
oscilloscope (Mode1 5223, Tektronox Inc., Beaverton. Oregon). For oxygen saturation.
visual verification that 0% oxyhemoglobin saturation (Le. disco~ection) registered as O volts
and that 100% oxyhemoglobin saturation registered as 1 volt occurred. Likewise, for hem-
rate, we confirmed the manufacturer's expected Iinearity of I volt representing a heart-rate of
255 beats per minute. This was accomplished by pmducing heart-rates ranging from O to 112
beats per minute and recording their corresponding voltages.
2.2.3.2b Measures of Gait
2.2.3.2bi Number of StridesJStride Length
A self-developed stride sensor using a piezo-electric transducer was placed
inside the heel of each subject's right shoe. The sensor was connected to charnel 5 of the
data acquisition system (Table 8). Whenever the heel of the subject's shoe made contact
with the ground during ambulation, a peak voltage was registered (Appendix 6). Output
from the stnde counter was used to derive stride length by dividing distance walked during
each six-minute walk test by number of strides taken. Validation of the stride counter
occurred prior to the commencement of data collection by comparing acquired data with
visual counting of the number of strides taken. Validation was perforrned at differing walking
speeds ranging from 45 meten per minute (rn/rnin) to 105 m/min. Perfect agreement was
found in each trial.
2.2.3.2bii Overall Walking Speed
For each walk test, overall walking speed was denved by dividing distance
walked in six-minutes by the duration of actual walking time (Le. duration of rest was
subtracted fiom the six-minutes).
2.2.3.2biii Modified Borg Rating of Leg Discornfort
The modified Borg scale is also a cornrnonly used tool to evaluate leg
discomfort during exercise (Kearon et al., 1991 ; Neely et al., 1991 ; Wilson & Jones, 1989).
At the start and completion of each six-minute walk test, subjects were asked to rate their
perceived leg discornfort using the modified Borg scale (Hamilton et al., 1996; Borg, 1982).
These values were documented on the data collection form (Appendix 3).
2.2.3.3 Explanatory Descriptive Measures
Demographic and descriptive data such as age, weight, height, supplemental
oxygen use and FEVl was extracted fkom each subject's medical chart and documented on
the data collection form (Appendix 3). In addition, the following measures were collected
for each subject.
2.2.3.3a Upper Extremity Weight-Bearing
In order to allow measurement of upper extremity weight-bearing when using
the rollator, the rollator (Opal Legacy, Therapist's Choice Medical Supplies, Toronto,
Ontario) was modified (without any change in functionality) by an engineer, to allow
incorporation of two force measuring aluminum beams. Two strain gauges (LY Series
Uniaxial Gauge, Omega Engineering Inc., Lavai, Quebec) were mounted on each beam. The
output of the force signal was amplified by self-made strain gauge amplifiers and connected
to channel 6 of the data acquisition system (Table 8). The weight-bearing sensing
mechanism was calibrated and zeroed on each study day. Prior to the commencement of data
collection, we calibrated the mechanism and established its linearity by comparing known
weight sources (Le. fYee weights verified by a universal scale with an error of 0.05 kilograms)
and the corresponding voltage output. This calibration was performed with a range of
weights ranging fiom 0.25 to 14.43 kilograms at each of the available heights of the rollator.
Linear regression analysis of these data showed that the relationship between weight applied
to the rollator and voltage output was linear over the range of weights measured (r=1.00,
p~0 .00 1). The linearity of the weight-bearing sensing mechanism is shown in Appendix 7.
2,2,3.3b Subject Preference
Subjects were requested to complete a standardized preference questionnaire
at completion of the study (Appendix 8). The preference questionnaire was intended to serve
as a means of determining each subject's preference for ambulation during the six-minute
walk test (i.e. with or with out rollator) and the reasons for this preference. This
questionnaire was piloted for content and clarity by two patients with COPD and clinicians
with expertise in respiratory rehabilitation. The questionnaire took approximately three
minutes to complete.
2.2.3.3~ Health-Related Quality of Life
Subjects were requested to complete the St. George's Respiratory
Questionnaire (SGRQ) during the study week (Appendix 9). The SGRQ is a disease-specific
instrument developed for individuals with COPD and designed to measure health-related
quality of life (Jones et al., 1992; Jones et al., 1991). The SGRQ c m be used as both an
evaluative and discriminative measure (Lacasse et al., 1997b). It contains 76 items divided
into three sections: symptoms, activity and impacts (Jones et al., 1991). This instrument was
self-administered, taking approximately ten minutes to complete (Jones et al., 199 1; Jones et
al., 1992). Subjects were reassured that there was "no right or wrong answer" and that they
should answer the questions as they interpreted them. The data collector was available to
provide clarification as necessary. Scores for each section and a total score were calculated.
Scores range from O to 100, with higher scores indicating poor health related quality of life
(Jones et al., 1992; Jones et al., 1991).
Additionaily, Chronic Respiratory Disease Questionnaire (CRQ) scores were
obtained from each subject's medical chart and documented on the data collection form
(Appendix 3). The CRQ is another disease specific health-related quality of life
questionnaire (Lacasse et al., 1997~); however, it is administered by a trained interviewer and
measures the domains of dyspnea, fatigue, emotional h c t i o n and mastery (Lacasse et al.,
1997~). It is primarily used as an evaluative mesure in clinical trials and treatment
prograrns; however the domains of fatigue, emotional function and mastery can be used to
discriminate arnong patients with less versus more severe quality of life loss (Lacasse et al.,
1997c)
2.2.4 Data Processing
Calibration and test files were transferred from the laptop computer to a desktop
computer using a parallel port data transfer cable and direct cable connection software
(Micmsofi Windows 98). Test files were imported into Excel (Microsoft, 1997) and were
split into six separate minute intervals. Variables were described and analyzed for the entire
six minute duration as well as for each individual minute of each walk test.
Mean oxygen saturation, heart-rate and upper-extremity weight-bearing were
determined using SigrnaStat statistical software 012.03, SPSS Inc, Chicago, Illinois).
Distance walked and number of strides were calculated in Excel (Microsofl, 1997).
Ventilatory variables (Le. respiratory rate, phase relationship of rib cage and
abdominal movements, minute volume and relative contribution of the nb cage and
abdominal compartments to breathing) were caiculated using a VI created by a biomedical
engineer using LabVIEW graphical programming software (V5.1, National uistments,
Austin, Texas). Respitrace inductive plethysmograph signals from each subj ect were
imported into the VI, calibrated using the signal fiom the Morgan Spiroflow, filtered in
accordance with Nyquist's sampling theory (Brook & Wynne, 1988) using the subject's
respiratory rate as the highest frequency component of the signal and analyzed in minute
intervals. The phase relationship of the nb cage and abdominal compartrnent was determined
by manually calculating and averaging the phase angles for the last three breaths of each
minute (Appendix 10). Zero degrees indicate that the signals are perfectly in phase (Le.
synchronous breathing) while 180 degrees indicate that signals of the rib cage and abdomen
are cornpletely out of phase (i.e. paradoxical breathing) [Gosselink et al., 19951. Minute
volume was determined by calculating and summing the difference (in litres) between the
peak and valley of each breath for the minute interval. Relative contribution of the rib cage
and abdominal compartments was determined by arbitrarily taking a ratio of the surface area
of n b cage excursion to the surface area of abdominal excursion. To aid in the interpretation
of these variables, data was collected on normal subjects (Appendix 1 1).
2.2.5 Statistical Analysis
For the primary and secondary meastues of interest, means, standard deviations and
standard errors were calculated for the six-minute w a k test conducted with and without the
rollator. Descriptive statistics were also used for the explanatory variables of interest such as
age, height, weight, FEVI, health related quality of life scores, subject preference and amount
of upper extremity weight-bearing. Pararnetric statistics were used for ratings of dyspnea and
leg discomfort due to the modified Borg scale's established ratio scale properties.
To detemine whether there was a difference between the prirnary and secondary
outcorne rneasures for the six-minute walk test conducted with and without the rollator, two-
way repeated measures analysis of variance (ANOVA) was used. When a significant
difference was found, post-hoc znalysis was performed using a Tukey test.
In order to determine which individuals would benefit most from using a rollator,
univariate regression was performed in order to explore the relationship between change in
functional exercise capacity (i.e. distance walked or perception of dyspnea) using the rollator
and specific independent variables (e.g. age. FEV!, use of supplemental oxygen). Stepwise
multiple regression analysis was then performed to determine the relationship between the
significant variables (as determined by univariate regression) and change in hinctional
exercise capacity using the rollator.
in order to determine if preference had an effect on outcorne, one-way ANOVA was
perfomed on the prirnary measures of interest between subjects who preferred using the
rollator, subjects who had no preference and subjects who preferred to walk unaided.
Additionally, chi-square analysis was performed to determine if level of disability was
related to preference.
Statistical analysis was undertaken using SigmaStat (V2.03, SPSS Inc, Chicago,
Illinois) and SigrnaPlot (V5.0, SPSS inc, Chicago, Illinois) statistical software. For al1
statistical analyses, p values of 0.05 or less were considered significant.
Chapter 3: Results
For each variable, results are given for the total sample (n=40) and for a subgroup of
subjects who walked less than 300 meters unaided (n=19). The latter was included based on
the data presented in section 3.4.1, which indicated a potential relationship between baseline
measure of disability (i.e. unaided six-minute walk test distance) and change in functional
exercise capacity using the rollator. Additionally, for the primary measures of interest, results
are given for subjects who waiked m e r than 300 meters unaided.
3.1 Samale Characteristics -
Twenty-one male and nineteen female subjects with severe COPD participated in the
study. Ten of the subjects required supplemental oxygen for exertion. Of the forty subjects,
nineteen walked less than 300 meters during the unaidrc! cil-minute walk test. General
charactenstics of the total sample and of those who walked less than 300 meters unaided are
shown in table 10.
3.2 Primarv Outcornes - 3.2.1 Six-Minute Walk Test Distance
There was no statistically significant difference in (mean i SE) six-minute walk test
distance using the rollator (R) compared to without (NR) for the total sarnple ([RI 3 17.0 2
15.7 vs. [MZ] 3 11.6 2 16.6 ml p=0.3) or for subjects who walked further than 300 meters
unaided ([RI 384.4 + 16.4 vs. w] 394.3 + 13.9 ml ~ 4 . 1 ) . However, subjects who walked
less [han 300 meters unaided, walked M e r with the rollator ([RI 242.5 + 14.2 vs. [NR]
220.3 + 12.0 ml p4.02). These results are illustrated in figure 2.
Table 10: General Characteristics of Sample
Il Age (years)
Variable
Sex
1 Supplernentai Oxygen Required (Umin) 1 l2
Total Sample ( ~ 4 0 )
21 male; 19 female
Weight (Kg)
Keight (cm)
Number (%) of Subjects on Supplemental Oxygen
FEV, (% Predicted) 36.1 5 2.0
Subjects Who Walked < 300 meters Unaided
(n=19) 12 male: 7 fernale
Total CRQ Score 78.9 2 3.4 81.425.1
7 1.2 2 2.3
165.8 2 1.5
10 (25.0%)
CRQ Dyspnea Domain Score 15.2 5 0.8 15.6 2 1.2
75.3 2 3.0
167.3 + 2.0
7 (36.8%)
CRQ Emotiond Function Domain Score 31.1 + 1.5 31.9 2 2.2 L
CRQ Fatigue Domain Score 15.2 2 0.8 15.3 2 1.2 i
11 CRQ ~Mastery Domain Score 1 17.1 2 0 . 9 1 17.8 t 1.2
SGRQ Total Score (%) 5 1.7 2 2.6
SGRQ Symptoms Score (%) 59.4 2 3.0
SGRQ Activity Score (%) 72.1 2 2.9 78.1 2 3.6
SGRQ Impacts Score (%) 37.8 2 3.1 37.3 2 5.0
Data are presented as mean 2 standard error (SE)
Figure 2: Cornparsion of total distance walked unaided (NR) and with rollator (R) for A) the total sample, 6) subjects who walked less than 300 meters unaided and C) subjects who walked greater than 300 meters unaided. Open circles represent individual data points. Solid squares represent mean + standard error.
Mean distance waked each minute of the six-minute walk test is shown for the total
sample and for subjects who walked less than and greater than 300 meters in figure 3. ui both
the total sample and the subgroup of subjects who waked less than 300 meters unaided, there
was a decline in distance walked during the middle of the six-minute walk test (i.e. minutes
two to four) and an increase in distance walked at the end portion of the test (i.e. minutes four
to six). This pattern was consistent regardless of rollator use and was not present for subjects
who waiked greater than 300 meten.
We examined the effect of the rollator on distance walked each minute of the six-
minute walk test in the total sample. Dunng the first minute, these subjects walked further
unaided ([RI 54.4 + 2.4 vs. [NR] 57.3 + 2.2 m, p<0.001); however, there was no significant
difference in distance walked for minutes two, three, Four, five or six (p>0.1). The
interaction between time (Le. minute) and aid was significant (pc0.001).
The sarne analysis was performed for the subgmup of subjects who walked less than
300 meters unaided. These subjects also walked significantly further wirhout the rollator
during the fint minute ([RI 44.1+ 2.2 vs. [NR] 47.8 + 1.8 m, p<O.OOl); however, they walked
significantly M e r wirh the rollator for minutes three ([RI 40.4 2 2.2 vs. [NR] 34.0 + 1.9 m,
p=0.01), four ([RI 35.7 + 3.1 vs. [M(] 28.3 2 3.2 m, p=0.03), five ([RI 37.3 + 3.5 vs. [NR]
3 1.4 + 3.5 m, p=0.02) and six ([RI 39.9 + 3.8 vs. IM(] 34.3 53 .9 m, p=0.02). The interaction
between thne (i.e. minute) and aid was also significant @<0.001) and distance waiked each
minute was l e s variable with use of the rollator (Figure 3B).
Minute Minute Minute
Figure 3: Mean + standard error distance walked unaided (NR] (closed circles) and with the rollator (RI (open circles) each minute of the six-minute walk test for A) the total sample, B) subjects who walked less than 300 meters unaided and C) subjects who walked greater than 300 meters unaided.
3.2.2 Duration of Rest
The change in rest duration is s h o w in figure 4. Subjects rested for 11.9 5.8
seconds using the rollator during the six-minute walk test compared to 31.2 + 8.7 seconds
without @=0.001). Similarly, a statistically significant reduction in duration of rest with the
rollator was also observed for subjects who walked less than 300 rneters unaided ([RI 24.3 f
11.6 vs [NR] 64.7 2 15.0 seconds, p<O.001). A cornparison of rest time for those who
walked further than 300 meten unaided was not performed, as only subject in this subgroup
required a rest.
3.2.3 Modified Borg Rating of Dyspnea
Use of the rollator resulted in a statistically significant reduction in the perception of
dyspnea, both for the total sample (IR] 1.8 + 0.2 vs. [NR] 2.7 + 0.3 unit change, peO.001)
and for those who walked less thon 300 meters unaided ([RI 1.8 + 0.3 vs. [NR] 3.2 5 0.4 unit
change, pc0.001). A statistically significant reduction in breathlessness with the rollator was
also found for those who walked further han 300 meters unaided ([RI 1.7 50.2 vs m] 2.2
+ 0.3 unit change, p=0.03). Figure 5 illustrates these results. Pre- and post-test dyspnea -
ratings for the total sarnple and those who walked less than and greater than 300 meters are
presented in table 1 1.
Figure 4: Camparison of duration of rest during the six-minute walk test when walking unaided (NR) and with the rollator (R) for A) the total sample and 8) subjects who walked less than 300 meters unaided. Open circles represent individual data pointssolid squares represent rnean + standard error.
3.3 Secondary Outcornes -
3.3.1 Cardiorespiratory Function
3.3.1.1 Ventilatory Variables
There was no significant difference in respiratmy rate during the six minutes,
with the rollator compared to without, for the total sample (p=0.4) or for those who walked
less than 300 meten unaided (p=0.8) [Figure 61.
The phase relationship of the rib cage and abdomen during the six-minute
walk test, with and without the rollator. is shown in figure 7. No statistically significant
difference was found for the total sample (p=0.6) or for those who walked less than 300
meters unaided (p=0.5).
Use of the rollator did not result in a significant change in minute voZtrme
during the six minute walk test for the total sample (p=0.4) or for those who walked less than
300 meters unaided (p=0.4). These results are illustrated in figure 8.
The ratio of the contribulion to breathing of the rib cage to abdomen was
not significantly different when using the rollator compared to walking unaided, for the total
sample (p4.8) or for those who walked less than 300 meters (p=0.8) [Figure 91.
Figure 6: Comparison of respiratory rate dunng the six-minute walk test when walking unaided (NR) and with the rollator (R) for A) the total sample and B) subjects who walked less than 300 meters unaided. Open circles represent individual data points. Solid squares represent mean 2 standard error.
Figure 7: Cornparison of the phase relationship of the rib cage and abdomen during the six-minute walk test when walking unaided (NR) and with the rollator for A) the total sample and 8) subjects who walked less than 300 meters unaided. Open circles represent individual data points. Solid squares represent rnean + standard error. -
Figure 8: Cornparison of minute volume during the six-minute walk test when watking unaided (NR) and with the rollator (R) for A) the total sample and 8) subjects who walked less than 300 meters unaided. Open circles represent individual data points. Solid squares respresent mean 2 standard error. Note that data was available for twenty and nine subjects, for Graphs A and B respectively.
Figure 9: Cornparison of the ratio of the contribution to breathing of the rib cage to the abdomen, during the six-minute walk test when walking unaided (NR) and with the rollator (R) for A) the total sample and 0 ) subjects who walked less than 300 meters unaided. Open circles represent individual data points. Solid squares represent mean + standard error. Note that data was available for twenty and nine subjects, for Graphs A and B respectively.
3.3.1.2 Oxygen Saturation and Heart-Rate
Use of the rollator did not result in a significant difference in oxygen
saturation during the six-rninute walk test, for the total sample (p=0.2) or for those who
waked less than 300 meten unaided (p=0.1) [Figure 1 O].
There was a statistically significant decrease in heart-rate using the rollator
during the six-minute walk test for the total sample ([RI 102.5 2 1.8 vs. [NR] 105.9 + 1.9
beats per minute, p=0.02). This difference was the result of lower hem-rates in minutes one
and six ( ~ ~ 0 . 0 3 ) ; however, this change was not clinically significant (Thomas, personal
communication). No significant difference was found for those who walked less than 300
rneters unaided (p=0.2). These resuits are illustrated in figure 1 1.
3.3.2 Gait
3.3.2.1 Stride Length
There was no difference in stride length during the six-minute walk test when
using the rollator cornpared to walicing unaided, for both the total sample (p=0.2) and for
those who walked less than 300 meten unaided (p=0.2) [Figure 121.
3.3.2.2 Overall Walking Speed
Use of the rollator resulted in a statistically significant reduction in walking
speed for the total sample ([RI 54.4 2 2.4 vs. [NR] 56.1 2 2.2 m/min, p=0.007); no difference
was observed for the subgroup of subjects who walked less than 300 meters unaided (p=0.1).
Fisure 13 depicts overall waking speed with and without the rollator.
Figure 10: Cornparison of oxygen saturation during the six-rninute walk test when walking unaided (NR) and with the rollator (R) for A) the total sample and B) subjects who walked less than 300 meters unaided. Open circles represent individual data points. Solid squares represent mean 2 standard error.
Figure II: Cornparison of heart-rate dunng the six-minute walk test when walking unaided (NR) and with the rollator (R) for A) the total sample and B) subjects who walked less than 300 meters unaided. Open circles represent individual data points. Sotid squares represent mean + standard error. -
Figure 12: Cornparison of stride length during the six-minute walk test when walking unaided (NR) and wi# the rollator (R) for A) the total sample and 8) subjects who walked less than 300 meters unaided. Open circles represent individual data points. Solid squares represent mean 2 standard error.
Figure 13: Cornparison of overall waiking speed during the six-minute walk test for walking unaided (NR) and with the rollator (R). Graph A depicts the total sarnple and graph B porûays subjects who walked less than 300 meters unaided. Open cîrcles represent individual data points. Solid squares represent mean + standard ertor.
3.3.2.3 Modified Borg Rating of Leg Discornfort
Use of the rollator also resulted in a statistically significant reduction in the
perception of leg discomfort for the total sample (CR] 0.3 2 0.1 vs. [NR] 0.5 2 0.2 unit
change, p=0.01); no significant difference was found for those who walked less than 300
meters unaided (p=O. 1) Figure 141. Note that the majority of subjects reported no change in
perception of leg discomfort kom the beginning to the end of six-minute walk test, both
when walking unaided and with the rollator. As a result, the disproportionate number of zero
values may have skewed the results. Additionaily, the clinical significance of this result is
questionable.
3.4 Ex~laaatorv Descriptive Measures -
3.4.1 Baseline (Le, Unaided) Six-Minute Walk Test Distance
Respiratory disability is oRen assessed by the six-minute walk test (Amencan
Thoracic Society, 1999). The literature suggests that a six-minute walk test distance of 300
meters is a potential threshold value for level of disability (Honeyman et al., 1996; Goldstein
et al, 1994). As such, we exarnined the relationship beiween baseline level of disability (Le.
unaided six-minute walk test distance) and change in distance waiked with use of the rollator.
Figure 15 illustrates that subjects who waiked less than 300 meten unaided tended to show
improvement in waking distance with the rollator, whereas those who were able to walk
greater than 300 meters, appeared to exhibit either no change or a detenoration in
performance.
Change in Modified Borg Rating of Leg Discornfort
Change in Modified Borg Rating of Leg Discornfort
O 1 O0 200 300 400 500 600 700
Unaided Six-Minute Walk Test Distance (m)
Figure 15: Scatter plot s howing the relationship between baseline measure of disability (i.e. unaided six-minute walk test distance) and change in distance walked with the rollator. Solid circles above dotted line indicate improvement in distance walked with the rollator while those below indicate deterioration. Solid line indicates that those who walked less than 300 meters unaided tended to show improvement in walk test distance with the rollator while those who walked greater than 300 meters appeared to exhibit either no change or a deterioration in performance.
3.4.2 Upper Extremity Weight-Bearing
During the six-minute waik test, the amount of upper extremity weight-bearing on the
rollator was 5.0 + 0.3 kg. This arnounted to 7.0 5 0.4 % body weight. Likewise, for those
who waiked less than 300 meters unaided, 5.5 & 0.5 kg of weight or 7.4 & 0.6 % body weight
was placed on the rollator. Table 12 shows the amount of upper extremity weight-bearing for
each minute of the six-minute walk test.
Table 12: Amount of Upper-Extrernity Weight Bearing During Each Minute of the Six- Minute Walk Test
Minute 1 Total Sample Subjects Who Walked < Subjects Who Walked 300 Meters Unaided > 300 ,Meters Unaided
Data are presented as mean 2 SE,
The relationship between the amount of weight applied to the rollator and change in
distance walked with the rollator (i.e. [RI distance walked - [NR] distance walked) was weak
and not significant for the total sample ( ~ û . 3 , p=0.1) and for subjects who waked less then
300 meten unaided ( d . 2 , p=0.4) [Figure 161. Similar hdings were found for the
relationship between the arnount of weight applied to the rollator and change in modified
Borg rating of dyspnea (60.3, pM.3) Figure 171.
O
Figure 16:
Weight Appiied to Roiiator (% Body Weight)
Weight Applied to Rollator (% Body Weight)
Relationship behveen amount of weight applied to rollator and change in distance walked with the rollator for A) the total sample and 6) subjects who walked less than 300 meters unaided. Solid circles above dotted line indicate improvement in distance walked wiai rollator while those below indicate deterioration.Solid line, calculated Iinear regression.
Change in Modified Borg Rating of Dyspnea [Rollator Change - Unaided Change]
Change in Modified Borg Rating of Dyspnea [Rollator Change - Unaided Change]
3.4.3 Sub ject Preference
Fifty percent of subjects (n=20) preferred using the rollator for the six-minute walk
test; 17.5% (n=7) had no preference and 32.5% (n=13) preferred to walk unaided. Fourteen
of the nineteen subjects who waiked less than 300 meters unaided preferred the rollator; one
had no preference and four preferred to waik unaided. The nurnber and percentage of
subjects' agreement with specific statements pertaining to the rollator (Appendix 8) are
shown in table 13.
Table 13: Agreement with Statements Pertaining to Use of the Rollator During the Six-Minute Walk Test for the Total Sample
No significant difference was found between subjects who preferred the mllator,
subjects who had no preference and subjects who preferred to walk unaided for change (i.e.
R-NR) in distance walked, modified Borg rating of dyspnea or duration of rest (one-way
ANOVA, pX.2). However, level of disability (Le. unaided six-minute walk test distance
greater or less than 300 meten) and preference were significantly related (Chi-square,
p=0.01) [Table 141.
Statement
Breathe Easier
Feel Safer
DifEcult to Push
Impaired Walking
Strongly Agree Or Agree
Count (%) 25 (62.5)
24 (60.0)
1 (2.5)
O (0.0)
Neither Agree Nor Disagree
Count (%) 1 1 (27.5)
9 (22.5)
1 (2.5)
6 (15.0)
Strongly Disagree Or Disagree
Count (%) 4 (10.0)
7 (17.5)
38 (95)
34 (85)
Table 14: Subject Preference Categorized According to Level of Disability
1 Subjects who Preferred Rollator 1 14
Subjects who Walked > 300 m
on the Six-Minute Walk Test
Subjects who Preferred to Walk Unaided or bad who had no
Preference
3.4.4 Univariate Regressioa Analysis
Baseline measures of impairment (i.e. FEV,), disability (Le. unaided six-minute walk
test distance less than or greater than 300 meters) and quality of life (Le. CRQ and SGRQ
5
scores) as well as other descriptive variables (i.e. use of supplemental oxygen, requirement of
a rest during the unaided six-minute walk test, baseline rating of dyspnea and age) were
evaluated as potential independent predictors of improvement in six-minute walk test
distance and perception of dyspnea with use of the rollator (Table 15). Simple regression
analysis revealed that unaided six-minute walk test distance and requirement of a rest during
the unaided six-minute wak test were significant for both improvement in six-minute waik
test distance and dyspnea sensation (Table 15).
Table 15: Univariate Regression Analysis Between Potential Predictor Variables and Improvement in
Uuaided Six-Minute Walk 40 Test Distance
(i.e. > or < 300 ml Health-Related Quality of 36
Life Scores+ Use of Supplemental 40
Oxygen Requirement of a Rest 40 During Unaided Six-
LMinute Walk Test Baseüne Modifted Borg 39
Rating of Dyspnea Aee 40
- - - - -- -- - - - -
* denotes statistical significance
WAlLKED DYSPNEA ,
R P Value n R P Value 0.15 0.42 36 O. 1 O 0.57 0.48 0.002" 39 0.38 0.02*
+ includes total and domain scores for CRQ and SGRQ
3.4.5 Multivariate Regression Analysis
Using the significant variables identified in simple linear regression (Le. unaided six-
minute walk test distance less than or greater than 300 meters and requirement of a rest
dunng the unaided six-minute walk test), multiple regression analysis (Le. stepwise
regression) revealed that requirement of a rest during the unaided six-minute walk test was
predictive of improvement in both distance walked and perception of dyspnea with the
rollator (Table 16). Unaided six-minute walk test distance did not significantly add to the
ability of the either mode1 to predict improvement (Table 16). This is likely to due to the
strong and significant relationship between the two variables (r= -0.67, p<0.001).
Table 16: Multiple Regression Analysis Between Predictor Variables Identified with Simple Linear Regression and Improvement in Functional Exercise Capacity (i.e. Distance Walked and Perception of Dyspnea) with Rollator
Unaided Six-Minute Walk Test Distance
(i.e. > or < 300 m)
Requirement of a Rest <O.OO 1 * During Unaided Six- Minute Walk Test
(R-NR) CHANGE m DYSPNEA
P Value
* denotes statistical significance
Chapter 4: Discussion
4.1 Summary -
Three research objectives were formulated for this study: to establish the short-term
effect of a rollator on lunetional exercise capacity in individuals with COPD, to determine
which individuals would benefit most fiom using a rollator and to provide insight into the
mechanisms that may be responsible for improvement in functional exercise capacity with
use of a rollator.
Our results indicate that use of a rollator results in an improvement in functional
exercise capacity in tenns of a reduction in breathlessness and a lessening of rest iime
required. Individuals with severe COPD who are unable to walk greater than 300 meters
and/or who require a rest during the six-minute walk test will benefit most From using a
rollator by reducing breathlessness and rest time and by improving distance walked. Finally,
we found that improvement in huictional exercise capacity with use of a rollator is not due to
changes in breathing pattern or gait.
This is the fint study to characterize which individuals with COPD benefit most from
using a rollator and to provide insight into the mechanisrns responsible for improvement in
functional exercise capacity with use of a rollator.
4.2 Cornparisons to Other Studies -
Our sample consisted of forty individuals (mean age 68 years), with puimonary
Function testing indicative of severe COPD (mean FEVi 36% predicted). Three previous
studies examining the effectiveness of wheeled walking aids in individuals with COPD also
evaluated individuals with severe COPD [mean FEVl 30-33% predicted] (Honeyman et al.,
1996; Wesmiller & H o h a n , 1994; Grant & Capel, 1972), while one used a less impaired
sample [mean FEVl 50% predicted] (Roomi et al., 1998). Honeyman and colleagues (1996)
and Roomi and colleagues (1998) samples were slightly older (71 and 75 yean), while those
of Wesmiller and Hoffman (1994) and Dalton and colleagues (1995) were slightly younger
(63 and 65 years). Sample sizes of these studies are considerably smaller than ours, ranging
hom one to twelve subjects (Roomi et al., 1998; Honeyman et al., 1996; Dalton et al., 1992;
Wesmiller & Ho f i a n , 1994; Grant & Capel, 1972; Campbell, 1957).
Our findings of an increase in distance walked in individuals who are most disabled
are consistent with those of Honeyman and colleagues (1996) and Wesmiller and H o h a n
(1994). Honeyman and colleagues found that individuals who walked l e s than 300 meters
during the six-minute walk test improved wak test distance by approximately 34 meten
when using a rollator. In this study, we reported an improvement of 22 meters. There were
slight differences in study design; Honeyman and colleagues (1 996) required subjects using
supplemental oxygen to pull their oxygen canisters only during the unaided six-minute waik
test. The increased metabolic cost t o m having to pull their portable oxygen may have
limited exercise capacity during the unaided wak test. Wesmiller and H o h a n (1994) also
found that the six individuals in their sample with twelve minute walk test distances of less
than 1000 feet (Le. 305 meten) walked 226 feet (Le. 69 meters) funher with the rollator.
Assuming that these findings could be extrapolated to performance on the six-minute walk
test, these individuals would have waiked approximately 34 meten m e r with the rollator.
This is the same value reported by Honeyrnan and colleagues (1996) and is somewhat
comparable to the results of our study.
We found that use of the rollator resulted in a one unit reduction in the perception of
dyspnea (i.e. on the modified Borg scale) for the total sample and a more pronounced effect
(i.e. 1.4 unit reduction) for those who were most disabled. These results are consistent with
Honeyman and colleagues (1 996) and Dalton and colleagues (1 995) who found a greater than
one unit reduction in perception of dyspnea associated with using a rollator.
Our finding of no change in oxygen saturation when using the rollator is consistent
with previous investigations (Roomi et al., 1998; Dalton et al., 1995). Although Honeyman
and colleagues (1996) reported a significant reduction in hypoxemia (Le. 2%) with use of a
rollator, the clinical importance of their finding is questionable. Honeyman and colleagues
(1996) did not provide baseline oxygen saturation values and therefore, it is difficult to
evaluate the clinical significance of the reduction in hypoxemia. When baseline oxygen
saturation is above 90%, a two percent difference is not reflective of a clinically important
change in the amount of oxygen dissolved in blood plasma. However, if baseline oxygen
saturation is below 85%, a two percent difference may be of greater clinical importance
(Frownfelter, 1996; Sherwood, 1993).
Our hding of no change in minute volume when using the rollator is in agreement
with the only snidy that evaluated the effect of a wheeled w a k n g aid on ventilation in
individuals with COPD (Grant & Capel, 1972). These researchen evaluated minute volume
with a Wright respirometer in their sample of five males with severe COPD and found no
change with use of a wheeled walking aid (Grant & Capel, 1972). Other studies have
reported reductions in minute ventilation with supported venus non-supported arms during
treadmill w a k n g in healthy individuals (Parrillo et al., 1991; Zeimetz et al., 1985).
However, ami support provided by a treadmill is not comparable to using a rollator.
Furthemore, while some studies have found treadmill and corridor floor walking tests to be
equivalent measures (Peeten & Mets, 1996; Beaumont et al., 1985), othen have found
significant differences in energy cost and performance (Stevens et al., 1999; Swerts et al.,
1990; Pearce et al., 1983). An individual is able to control hislher walking speed when
performing a corridor test, whereas the speed of walking is externally controlled during a
treadmill evaluation.
Grant and Cape1 (1972) explored the effect of a wheeled walking aid on overall
walking speed in individuals with COPD. They found a 3.7 m/min reduction in wallcing
speed associated with an improvement in distance walked. The improvernent in distance
walked occurred by an increase in endurance because the evaluative walk tests were not
tirne-limited and subjects were allowed to walk as far they could. Although we found no
overall difference in six-minute walk test distance, use of the rollator resulted in a 1.7dmin
reduction in walking speed. Convenely, while we did find an improvement in distance
walked with the rollator for our subgroup, no significant change in walking speed was found.
This is the first study to investigate the effect of a wheeled walking aid on heart-rate,
respiratory rate, respiratory pattern, perception of leg discornfort and stride length in
individuals with COPD. We found no statistically and/or clinically significant change in any
of these variables walking with the rollator compared to without in both our total sample and
subgroup.
4.3 Research Ouestions 1 & 2 - Determinine the Effect o f a Rollator on Functional
Exercise Ca~acitv and the Individuals Who Ben efit Most
Functional capacity has been defined as the ability to undertake physically demanding
activities of daily living (Guyatt et al., 1985a). Calverley (2000b) has suggested that the
improvement of an intervention on functional exercise capacity can be manifested in one of
two ways for individuals with COPD. Individuals may choose to exercise to the same level
of breathlessness as previously, but because they are less distressed, they are able to walk
further (Calverley, 2000b). Alternatively, they may walk the same distance, but experience
less breathlessness (Calverley, 2000b). Using these standards, our findings show that use of a
rollator improves functional exercise capacity by reducing the perception of dyspnea. For
individuals who are unable to walk further than 300 meten and/or who require a rest during
the six-minute walk test, use of a rollator results in a more pronounced improvement in
functional exercise capacity by reducing the perception of dyspnea while at the same time
increasing distance walked.
The improvement in distance walked by our subgroup of subjects who walked less
than 300 meters was 22 meters. Redelmeier and colleagues (1997) established that a minimal
mean change in six-minute walk test distance of 54 rneten represented a clinically significant
change in hct ional status. Using this cntenon, our results are not clinically significant.
However, Redelmeier and colleagues (1997) used a COPD population with an average six-
minute walk test distance of 371 meters. Given that our subgroup walked 220 meters during
the unaided six-minute walk test, a less than 54 meter change in distance walked may be
clinically significant. The majority of the subgroup (Le. 74%) preferred using the rollator for
the walk test, indicating that the improvement was clinically important.
Dyspnea is the distressful sensation of uncornfortable breathing and shortness of
breath (Breslin, 1992). It is the most comrnon syrnptom that limits function and exercise in
individuals with COPD and as such, sorne authon argue that it should be regarded as a
primary outcome rneasure in any study that evaluates the success of an intervention in this
population (O'Donnell, 1998; O'Domeli et al., 1995; Jenkins et al., 1995). Although there is
no published information on what precisely constitutes clinical improvement for the
perception of dyspnea using the modified Borg scale, clinical experience suggests that a one
unit or greater reduction is clinically important (O'Domeli, persona1 communication). Using
this criterion, our results pertaining to the effect of a rollator on breathlessness are considered
clinically significant. This is further supported by the fact that the majority of subjects (Le.
63%) felt that the rûllator allowed them to breathe easier during the walk tests.
The outcome of duration of rest has received little attention in the literature. Menard-
Rothe and colleagues (1 997) reviewed studies evaluating exercise tolerance using time-based
fùnctional waik tests and found that no investigation reported the total rest time taken during
performance of the walk tests. It is difficult to accurately interpret the full extent of
fûnctional capacity (e.g. independent comrnunity ambulation) with the absence of such
information (Menard-Rothe et al., 1997). Our findings of reduction in rest time for the total
sample (i.e. 19 seconds) and subgroup of subjects who walked less than 300 meten (Le. 40
seconds) has important implications, especially since a reduction in dyspnea and an increase
in distance walked (Le. subgroup only) occurred concurrently. To be able to rest for a shorter
period of time, experience less shortness of breath yet still walk M e r in the same time
period with a rollator compared to without, is considered an irnprovement in functional
ability and is therefore assumed to be meaningful to an individual (Menard-Rothe et al.,
1997).
4.3.1 Clinical Implications of Findings
An individual with severe COPD who walks less than 300 meten andlor who requires
a rest during the six-minute walk test will benefit most from using a rollator. It is also
important to have an understanding of the patient's circumstances, values and beliefs and
incorporate them into each clinical recomrnendation (Guyatt et al., 2000; McAlister et al.,
2000). Although we established the positive effect of a rollator on hctional exercise
capacity (i.e. reduction of breathlessness, decrease in rest time required and improvement in
distance walked) for individuals with severe COPD, 33% of our total sample and 2 1 % of our
subgoup preferred to walk unaided. Patient concems of the 'stigrna' associated with using a
mobility aid, appearance of the aid, cost and perception of benefit must also be taken into
consideration.
From a clinical perspective, this study may have underestimated the effect of' a
rollator on functional capacity in individuals with severe COPD. Some of the advantageous
features of a rollator were not considered. First, because equipment modification was
necessary to allow the incorporation of an upper extremity weight-bearing sensing
mechanism. the seat of the rollator was removed. Having a seat readily available allows an
individual the security of knowing helshe is able to rest anywhere at anytime. This feature
rnay serve to reduce the anxiety and fear many individuals with COPD have when embarking
on community ambulation. Second, this study did not make use of the basket attached to the
rollator. This feature allows individuals to cany persona1 belongings a d o r shopping
purchases. Most importantly, for individuals who require supplemental oxygen, the basket
allows housing of the portable oxygen canister. Typically, individuals carry their oxygen
canisters on a cart or with a shoulder strap. In this study, the oxygen canister was carried on
the tester's trolley for both the independent and 'rollator' walk tests. The reduction in
metabolic cost frorn not having to pull their portable oxygen may result in hinher
improvements in hinctional exercise capacity (Honeyrnan et al., 1996).
Research Ouestion 3 - Ins i~h t into Mechanims
This is the fint study to provide insight into some of the potential mechanisms that
may be responsible for improvement in functional exercise capacity with use of a rollator in
individuals with COPD.
The clinical importance of observing the synchrony of motion of the nb cage and
abdomen (Le. breathing pattern) has been supported in the Iiterature (Macklem, 1980; Sharp
et al., 1977; Ashutosh et al., 1975). Asynchronous or paradoxical motion between the two
compartments suggests ineffective diaphragmatic function (Siafakas et al., 1995; Celli et al.,
1986; Gilbert et al., 1981; Ashutosh et al., 1975; Sharp et al., 1977). With ineffective
diaphragmatic function, the inability to generate effective inspiratory force results in the
diaphragm being moved upwards by the negative intrathoracic pressure generated by the
intercostal muscles (Delgado et al., 1982; Sharp et al., 1977). While previous studies have
used qualitative evaluations of the phase relationship of the rib cage and abdomen (Breslin et
al., 1990; Celli et al., 1986), we were able to quanti@ the extent of asynchronous movement.
Nevertheless, our hypothesis that change in breathing pattern induced by the rollator, was not
supported. In fact, no significant differences in any of the ventilatory variables studied were
found when w a h g unaided compared with using the rollator. Although no previous study
has evaluated diaphragmatic function, investigations showing positive effects of wheeled
walking aids for individuals with COPD have used high-wheeled waiking aids (Roomi et al.,
1998; Grant & Capel, 1972; Campbell, 1957) or have adjusted the height of the aid for
comfort (Wesmiller & H o h a n , 1994). in contrast, we standardized the height of the rollator
by using the approach most clinicians adopt when prescribing walking fiames (Pierson,
1994; Hall et al., 1990). Specifically, we ensured that the handle bars of the rollator were at
the level of the subject's ulnar styloid process (Pierson, 1994; Hall et al., 1990). It is possible
that the height of rollator may have been too low to facilitate the 'forward lean' position that
is thought to improve diaphragmatic f ic t ion and therefore optirnize the work of breathing in
individuals with COPD.
The complex interplay of physiological and psychological fac ton causing dyspnea
makes it difficult to evaluate (07Donnell, 1998; Ienkins et al., 1995; Breslin, 1992).
Although the sensation of dyspnea has been correlated with respiratory rate, minute
ventilation, accessory muscle recruitment and activity, chest wall asynchrony and emotional
statu, its rnechanisrns are not cornpietely understood in individuals with COPD (Lanon et
al., 1996; Breslin, 1992). Our finding of a decrease in the perception of dyspnea for al1
subjects but no change in any of the ventilatory variables is interesting. However, we did not
evaluate accessory muscle activity. It is possible that the reduction in perception of dyspnea
found with using the rollator may have been associated with a reduction in accessory muscle
activity and recmitment (Breslin, 1992; Breslin et al., 1990). It also is important to recognize
the multidirnensional nature of respiratory sensations that include not only sensory aspects
but also affective and cognitive components (Altose, 1985). During exercise, an individual
may breathe very hard and not experience the sensation of dyspnea, because such exertion is
not accompanied by a sense of anxiety over the adequacy of ventilation (Shenvood, 1993).
The sensation of dyspnea may occur without a corresponding change in ventilation or gas
exchange (Sherwood, 1993).
This is the fint study to evaluate weight transfer with use of a rollator. We did not
find a significant relationship between amount of weight applied to the rollator and change in
functional exercise capacity (i.e. distance walked or perception of dyspnea). We can infer
Born this that the extent of improvement in functional exercise capacity with use of a rollator
is not dependent on the amount of weight applied to the rollator. However, this does not
preclude that the allowance of arm support provided by the rollator may have contributed to
the observed improvement. Specifically, it may have been the mere provision of support,
regardless of the arnount of weight transfer, that resulted in the improvement. The majority of
subjects (i.e. 60%) felt safer when using the rollator compared to without. It is possible that
the increased security provided by the support of the rollator contributed to the reduction in
the perception of breathlessness by decreasing fear and anxiety. Alterations in emotional
state can effect the cognitive processing of sensory information and perception of
breathlessness (Pandolf, 1983). The effect of am support on the perception of dyspnea has
not been reported previously.
Measures of gait (e.g. stride length) have been shown to be altered with training and
when using different types of wheeled w&ng aids (Bohannon, 1997; Mahoney et al., 1992;
McGavin et al., 1977). Mahoney and colleagues (1992) found that individuds waiked with
longer strides when using a three versus a two-wheeled walker. McGavin and colleagues
(1977) found that mean stride length during a time-based waik
with training in men with COPD. They questioned whether this
test increased significantly
change was due to a more
efficient w a h g pattern. As such, we evaluated stride length to assess if this gross measure
of gait changed when using a rollator compared to without. Our finding no difference in
stride length suggests that gait alteration was not a rnechanisrn responsible for change in
fùnctional exercise capacity with use of a rollator.
We also considered whether use of a rollator would lead to change in walking speed.
Increases in walkîng distance with use of a wheeled walking aid in individuals with COPD
have been associated with reductions in walking speed (Grant & Capel, 1972). Likewise,
speed of walking has been shown to be altered when using different types of wheeled
walking aids (Cornely et al., 1997; Mahoney et al., 1992; Bohannon, 1977). Mahoney and
colleagues (1992) lound that older individuals walked faster with a three versus a two-
wheeled walker and Comely and colleagues (1997) found faster walking speeds associated
with use of a rollator versus a two-wheeled walker. Our findings suggest that change in
overall walking speed per se was not responsible for the observed change in functional
exercise capacity (Le. reduced breathlessness, reduced rest time and improved walk test
distance [subgmup only]) with use of a rollator. However, it did appear that use of the
rollator might have reduced minute to minute variability in distance waked during the six
minutes (Le. improved pacing), especially for those who walked less than 300 meters unaided
(Figure 3).
4.5 Limitations -
There are several limitations to this study that must be considered. Due to the nature
of the study, the tester was not blinded. Lack of blinding may provide different
interpretations of marginal findings or differential encouragement during performance tests,
either one of which can distort results (Guyatt et al., 1993; Guyatt et al., 1984). To minimize
potential bias, data collection for the rnajority of rneasures (Le. six-minute walk test distance,
cardiorespiratory variables and gait measures) was automated. For those measures that were
manually collected (i.e. modified Borg ratings of dyspnea and leg discornfort, duration of
rest), a standardized protocol was followed. Likewise, the six-minute walk test was
administered in accordance with standardized instructions and no encouragement.
Although we gained insight into ventilatory changes with use of a rollator, these were
measured indirectly. Respiratory inductance plethysmography is a non-invasive technique
used to evaluate breathing volumes and pattern. The estimation of thoracic and abdominal
volumes contributing to each breath is based on measurement of the rib cage and abdominal
wall motion (Stromberg et al., 1993; Verschakelen et al., 1989; Stradling et al., 1985; Chadha
et al., 1982). Measurement of variables such as the synchrony of rib cage and abdominal
motion (Le. phase relationship of the thorax and abdomen to breathing) and minute volume
allow an indirect evaluation of diaphragmatic f ic t ion and work of breathing (Verschakelen
et al., 1989; Tobin et al., 1983). While direct assessments are possible (i.e. measuring
esophageal, gastric, intrapleural and transdiaphragmatic pressures using balloon or micro-
pressure transducer catheter systems passing through the nose), these measures are invasive
and often uncornfortable (Sanna et al., 1999; Gilbert et al., 1981; Sharp et al., 1980).
We did not evaluate accessory muscle activity. Sharp and colleagues (1980)
suggested that accessory muscle activity might be optirnized when the arms are supported.
Additionally, increased accessory muscle use is believed to enhance dyspnea sensation
(O'Domell, 1995; Delgado et al., 1982; Sharp et al., 1977). Previous studies have evaluated
accessory muscle activity using electromyograms (EMG) via surface electrodes of the
stemocleidomastoid muscle (Martinez et al., 199 1 ; Sharp et al., 1980). However, the artefact
associated with EMG during comdor walking made it difficult to incorporate this measure
into the study.
The six-minute walk test was conducted in an artificial environment. In accordance
with recommendations in the literature, we administered the six-minute walk test in an indoor
corridor, free of distractions (Bittner, 1997). Furthermore, due to the nature of the study, data
collection necessitated the use of extraneous winng and equipment, not typically present in
day-to-day life. However, performance on the six-minute walk test has been found to be a
valid measure of functional exercise capacity in individuals with COPD (Table 3) and has
recently been show to closely parallel the level of activity that individuals are most likely to
perfom regularly in their daily lives (Steele et al., 2000).
Finally, the study descnbed in this thesis provides insight only into the short-terni
benefit of using a rollator. Individuals with COPD typically report a decrease in their
capacity to perfom routine activities of daily living due to symptoms of dyspnea and Fatigue
(Lareau et al., 1996). From the individual's perspective, the ability to remain active is ofien
the most important outcome of medical care (Deyo & Patrick, 1989). Although o w study
found an improvement in functional exercise capacity with use of a rollator, it remains
unknown whether the use of a rollator would facilitate an individual's ability to remain
active, and prevent the deconditioning, worsening of symptoms and reduced quality of life
that often occurs with COPD (Canadian Respiratory Review Panel, 1998).
Chapter 5: Conclusions and Recommendations for Future Research
5.1 Concludine Remarks - The aims of the study descnbed in this thesis were three-fold; fint, to determine the
short-term effect of using a rollator on functional exercise capacity in individuals with
COPD; second, to establish which individuals would benefit most ffom using a rollator; and
third, to provide insight into the underlying mechanisms that may contribute to change in
functional exercise capacity with use of a rollator. The results described herein provide
evidence that use of a rollator increases functional exercise capacity (Le. reduces
breathlessness and duration of rest required) in individuals with severe COPD. It was further
determined that individuals who walk less than 300 meters a d o r who require a rest during
an unaided six-minute walk test will benefit most (Le. reduction of breathlessness, reduction
in rest time and improvement in distance walked) fiom using a rollator. Finally, evidence
was provided that the improvement in functional exercise capacity observed with using a
rollator was not due to changes in breathing pattern or gait.
5.2 Future Research -
The study descnbed in this thesis has raised several additional questions related to the
use of a rollator in individuals with COPD and has pointed to further investigations that
would be needed to answer these questions. Recommendations for research include
conducting studies on the long-term use and effect of rollaton to establish whether they
contribute to sustained improvement in functional statu. Additionally, the effect of height of
the rollator on respiratory responses and functional outcomes remains unclear. hsight into
the effect of a rollator on accessory muscle use would aiso be worthwhile. Finally, given the
beneficial effect of a rollator on functional exercise capacity for individuals most disabled by
COPD, a cornparison of the effect of a rollator to other interventions (e.g. supplemental
oxygen) warrants evaluation.
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APPENDIX 1
Eligibility Screening Form
ROLLATOR STUDY ELIGIBILITY SCREENING FORM Contact: Sherra Solwav x4510
Subject Name:
1 . Diagnosis of COPD
2. Clinically Stable
3. 55-85 Years Old
4. Unaccustomed to Use of Rollator
5. Able to Walk Unaided
6. Able to communicate in English
If no, language spoken:
7. Coexisting symptomatic disease that contributes to exertional dyspnea or limits exercise ability/tolerance
If yes, speci fy:
ELIGIBLE?
Tel:
ELIGIBLE
- YES
- YES
- YES
- YES
- E S
- YES
INELIGIBLE
- - -- - - - -- -
Physician Name:
Physician Signature: Date:
APPENDIX 2
Subject Information Sheet and Informed Consent Form
Rollutor Study
Subject Lnforrnation Sheet
Contacts: S u n n a Mangovski Akamora (416-243-3600 x 2264) Dr. Dina Brooks & Sherra Solway (41 6-243-3600 ~ 4 5 1 0 )
Pur~ose of Studv: The purpose of this study is to compare the ability to walk and feelings of breathlessness with and without a rollator (wheeled walker) in individuals with chronic obstructive pulmonary disease.
Descri~tion of Studv: Participation in this study will involve simple tests of walkmg and a questionnaire sirnilar to those you have cornpleted as part of yow rehabilitation. In addition, a belt will be placed around your abdomen and chest cavity to rneasure your breathing. During the study, you will be asked to walk for six minutes with and without a rollator, on two separate days in the same week.
Benefits: There will be no direct benefit for participating in this study. However. the results of this study may benefit patients with chronic obstructive pulrnonary disease by helping health care professionals understand the effect of a rollator on shortness of breath and distance walked.
Potential Harm: There are no known physical, ernotional or social harms associated with participation.
Confidentialitv: Confidentiaiity will be respected and no information regarding your identity will be released or published without your consent. A copy of the results will be avaiiable to you if requested.
Pat-tici~ation: You rnay refuse to participate in ths study or withdraw fiom it at any time during its course. Your withdrawal will not jeopardize your relationship with West Park Hospital and will have no influence on your medical management.
Please c d Sherta Solway @ 41 6243-36OU ~ 4 5 1 0 ifyou have any questions or concem.
Rollator Study
Informed Consent Form
1 have read the Subject Information Sheet. The research study and procedures have been explained to me and
any questions have been answered to my satisfaction. The potential harrns and discornforts have been explained
to me and 1 also understand the benefits to participating in this study. 1 know that I may ask now, or in the
future, any questions 1 have about the study or research procedures. 1 have been assured that records reiating to
my care will be kept confidential and no information will be released or printed that would disclose my personal
identity without my permission. 1 am aware of my option to refiise to participate in this study or to withdraw
from it at any time during its course. 1 understand that my withdrawal will not jeoprirdize my relationship with
West Park Hospital and will have no influence on my medical management.
Patient Name Signature Date
Investigator Signature Date
W i tness Signature Date
APPENDK 3
Data Collection Form
Age Weight
1 CR0 Score 1 Total: D: E: F: M: 1
Date:
Oxygen? Stage of Rehabilitation
No Y es Vmin for exertion
E ffort/Discomfort Scale BIood Pressure
Test 2: Rollutor: Y es No
Distance Walked # Rests Duration of Rests
Modified Borg Dyspnea Scaie Modified Borg Leg
Comments:
Pre-Test
Distance Walked # Rests Duration of Rests
Post-Tes t 7
Test 2: Rollator: Yes No
Comments:
f
Modified Borg Dyspaea Scale Modified Borg Leg E ffort/Discomfort Scale BIood Pressure
Pre-Test Pos t-Tes t
1
Date:
[ BIood Pressure I I
Test 3: Rollator: Y es No
Distance Walked # Rests Duration of Rests
Comments:
Post-Test Modified Borg Dyspnea Scale Modified Borg Leg EfforüDiscomfort Scale
Pre-Tes t
Modifled Borg Dyspnea Scale Modified Borg Leg E ffort/Discomfort Scale
Test 4: Rollator: Y es No
[ Blood Pressure
Pre-Test
r
Distance Walked # Rests Duration of Rests
Post-Test
Comments:
.MPENDIX 4
Modified Borg Scaie
NOTHING AT ALL uust noticeable)
VERY VERY SLIGHT
VERY SLIGHT
SLIGHT
MODERATE
SOMEWHAT SEVERE
SEVERE
VERY SEVERE
VERY VERY SEVERE (aimost maximal)
MAXIMAL
APPENDIX 5
Equations for Respiratory Inductance Plethysmography Calibration
Calculation of calibration factors requires the solution of two simultaneous equations, each involving the rib cage, abdominal and standard measurements (Cohn et al., 1982; Chadha et al., 1982; Respitrace Manual, 1979).
General Formulas:
To Solve for x and y:
x = [(A'*v') - (A'*v')] I [(R'*A') - (R'*A')]
y = [(R'*v') - (R'*v')] / [(R'*A?) - (R'*A')]
Where:
x = calibration factor for rib cage
y = calibration factor for abdomen
A' = abdomen measurement at point 1
A' = abdomen measurement at point 2
R' = rib cage measurement at point 1
R' = rib cage measurement at point 2
V' = standard volume measurement at point 1
V' = standard volume measurement at point 2
APPENDIX 6
Stride Sensor Output
APPEN'DIX 7
Validation of Upper Extremity Weight-Bearing Sensing Mechanism
1 1 1 I I 1 L I 1
O 2 4 6 8 10 12 14 16
True Weight (kg)
Figure II: Relationship between known weights applied to rollator and output of weight-bearing sensing mechanism. Solid line. calculated linear regression.
APPENDIX 8
Su bject Preference Questionnaire
Subiect Preference Ouestionnaire
Subject Name:
1. During the walk test, did you prefer to walk:
Cl with the rollator
a without the rollator
O no preference
2. Please CTRCLE your level of agreement with the following statements:
The rollator allowed me tu breathe easier ivhen I walked.
1 2 3 4 S trongIy Disagree Disagee Neither .4gree Agree
nor Disagree
The rollator made me feel safer when I walked.
1 2 3 Strongiy Disagree Disagree Neither Agree
nor Disagree
1 - 7 3 Strongly Disagree Disagree Neither Agree
nor Disagree
4 Agree
5 Strongiy Agree
5 Strongly Agree
5 Strongly Agree
The rollator impaired m-v ability to walk.
1 - 3 3 Strongly Disagree Disagree Neither Agree
nor Disagree
3. Do you have any other comments about the rollator?
4 Agree
5 S trongly Agree
APPENDIX 9
St. George's Respiratory Questionnaire
This quest ionne is designed to help US leam much more about how your bnalhing is mubling you and how it affects your l i f ~ We are using it to find out which aspects of your illness cause you most problem. mthcr lhan what the doctors and nurses th0ink your problems
Pleare w d the inrtNction. carefully and ask if you do not understand any thing. Do not spend too long deciding about your answen
Sex: MaleFemate
J 2 A R r l
]ESTIONS ABOW HOW MUCH CHEST TROUBLE YOU HAVE HAD OVER ?HE LAST YEAR
EASE TICK IN ONE BOX FûR EACH QUESTION.
most days a week
severai days a week O -
O
cl cl
a few days a week
only wirh c hes t
infections
cl
not at all
O
cl 0
. a
1) Over the last year. 1 have coughed:
2) Over the 1 s t year. 1 have brought l p phlegm (sputum) : 3 ) Over the last year, 1 have had jhortness of breath :
9 Over the last year. 1 have had amcks 3f wheering :
During the last year. how many severe or very unpleasant attackr of chest trouble have you had :
more than 3 attacks. ................... 3 attacks.. ............. .. ............... CI
2 atracks., CI
.............................. 1 attack.
O .................... /""""""
no attacks. cl
.............................. cl 1 How long did the wont attack of chest trouble last: i o LO Question 7 if you had no severe atucks)
a week or more. . . . . . . . .O. . . . . . . . . . . . , . 3 or more days
a .........................
1 or 2 days Q
............................. less than a day
cl ......................... C1
1 Over the last year. in an average wctk. how many good days vi th linle chest trouble) have you had:
no good 'days ........................... 1 or 2 good days..
O .....................
3 or 4 good days 0
....................... o nead y every day is good.. ............ O every day is good.. .................... cl
1 IE you have a wheem. is it worse in the morning: 1
no -....................................... Q yes.. ..................................... O
. * U K U
m [OW wow YOU DESCRIBE YOUR CHEST C O N D ~ O N ? (PLEASE n a IN ONE BOX ONLY)
h e most important problem 1 have. ......... A.. ................................
causes me a few problems ...........................*............................. causes no problem.. ................................................................
= YOU HAVE EVER HAD PAID E M P L O Y M ~ , PLEASE TICK ONE OFTHESE: my chest trouble made me stop work ............................................
... my chest trouble interferes wilh my work or made me change my work ....................................... my chest trouble does not affect my work
N ?; QUESTIONS A B O m WHAT ACïNmES U S U W Y WUCE YOU FEEL BREATHIlESS I lESE
. . TRUE Sltting or lying srill. .............................................. Getting washed or dressed
O ......................................
Walking around the home.. O
..................................... Walking outside on the level..
CI ..................................
Walking up a flight of stairs -0
..................................... a Walking hills ...................................................... a a Playing sports or p m e s ......................................... cl a
E m O N 3 : SOME MORE QUESTIONS ADOüT YOUR COUGH AND BREATIUESSMSS y - ! E D AYS.
3R FACH TTEM, PLEASE TICK ElTHER TRUE OR FALSE AS ïï APPLIES TO YOU.
........................... ....................... My cough hum ;
My cough makes me tired ....................................... 1 am breathless when 1 talk ..................................... I am breathless when I bend over.. ..;. ... :. ................... My cough or breathing disturbs rny sleep.. ...................
. 1 get exhausted easily.. ..........................................
TRUE FALSE a cl O O c! cl CI D O a O O
........... My cough or breathing is embarrassirtg in public. My chest trouble is a nuisance CO my family. friends or
....... ............................................... neig h bours ,.
- I get draid or panic when 1 cannot get my breath ............ 1 feel that I am not in control of my chest problern ...........
..................... I do not expect my chest to get any better
..... 1 have becorne fiail or an invalid because of my chest..
Exercise is not safe for me.. .................................... Everything seems too much of an effort .......................
TRUE O O
I G H ï TO SECTION 6. 3MPLE"iE TKIS SECIION PLEASE TICK EITHER ?RUE OR FALSE AS APPLEES TO YOU.
TRUE F U E My medication does not help me very much .................. cl cl 1 ger embarrasxd using my medication in public ............ I have unpleasant side effects from my medication
a 0 ...........
My medication interferes with my life a lot.. cl cl.
................. / 11 Q
n O N 6 : THESE ARE QUESTïONS ABOUT HOW YOUR ACTIVITIES MIGKT BE BY YOUR
ATHING. TiCK
EACH QUESTiON, PLEASE~RUE IF ONE OR MORE PARTS APPLES TO YOU BECAUSE OF YO- - - -
1 uke a long time to get washed or dressed ................... I cnnnot take a bath or shower. or 1 wke a long time ......... 1 walk slower than other people. or 1 stop for rests .......... Jobs such as housework take a long tikc or 1 have to stop
............................................................ for rests If 1 walk up one flight of staiis. 1 have to go slowly or
C stop.*. .**.- ......................................................... If 1 hurry or walk fast. 1 have to stop or s low
- down ........-...... ... ........................................... My brealhing rnakes ir difficult to do things such as walk up hills. carrying things up stairs. light gardening such as
..................... weeding. dance. play bowls or play golf
h ë w y loads.dig the garde* or shovel snow. jog or waiic i t 0 ....................... 5 miles per hour. play tennis or swim ..
My breahing makci it difficult to do things nich as very hcavy manual work. run. cycle. swim fast or olav a ~ f i m n a p : ~ : r . . r - - - - - -
E. .EASE TiCK EITHER TRLTE OR FALSE AS IT' APl'UES TO YOU OF YO-.T
EMEMBER 'IHAT TRUE ONLY APPL~ES TO YOU t~ YOU CAN NOT w SOMFIHING BECAUSE OF YOUR
LIRUE ... ............................ I cannot play sports or games. ;..
1 cannot go out for entenainment or recreation. cl
............... 1 cannot go out of the house to do the shopping..
cl ............ cl
.......................................... I cannot do housework 5 1 cannot move far [rom my bed or chair. ...................... O
ERE IS A LIST OF OTHER ACITVXES THAT YOUR CHESI' 'IROUBU MAY PRRrENT YOU WING. (YOU DO
OT HAVE TQ TICK THESE, TKEY ARE JUST TO REMIND YOU OF WAYS IN - WHICH YOUR B-THLESSNESS
[AY AFFECT YOU) :
GONG FOR WALKS OR WALKING THE DOG
DONG THINGS AT HOME OR IN THE GARDEN
SEMJAL NIERCOURSE
GOING OUT TO CHURCH, OR PLACE OF ENTERTADIMENT
GûING OUT IN BAD WEATHER OR SMOKY ROOMS /'
'LEME WRITE Dl ANY OTHER IMPORTANT
~OW. W O U YOU Ti= INTHE BOX (ONE ONLY) WWCH YOU 'IHTMC BEST DESCRïBES HOW YOUR :HEST AFFErn YOU:
It does not stop me doing anything 1 would like to do ....... Q a
...... It stops me doing one or two things I woÜld like to do 0
..... Ir stops me doing most of the things 1 would like to do a . Il stops me doing everything I would like to do.. ............ a -
HAMC YOU FOR FILLING IN THIS QUESTiONNAIRE. BEFORE YOU =SH WOULD YOU HECK TO SEE ?HAT YOU HAVE ANSWERED ALL TKE QWTIONS.
APPENDU 10
Calculation Procedure for Phase Angles
I+bdomeq
R ; b Caye
Phase Angle = (B - A) /(C - A) r 360 degrees
APPENDLX 11
Normal Respiratory Data
RESPIRATORY RATE
Normal I
Post Test 1 13.5 14
MINUTE Pre Test
1
6 Minute Average 1 13.3 11.8 - -- '.. - -
Normal 2 1 MINUTE 1 NO ROLLATOR 1 ROLLATOR 1
NO ROLLATOR 15.5 15.5
II Pre Test 1 15.5 1 17 II
ROLLATOR 16 13
Normal 3 MINUTE Pre Test
- -. . . - .
E = unable to determine due to poor quality of data
NO ROLLATOR 1 ROLLATOR 21 E
2 3 4 5 6
Post Test 6 Minute Average
- --
25 25 28
26.5 26
20.5 25.9
Normal 4
25 26
25.5 25 28
23.5 25.3
MINUTE Pre Test
1 2 3 4 5 6
Post Test
3 e E = unabIe to determine due to poor quaIity of data
NO ROLLATOR 16.5 E E E E E 30 25 E
ROLLATOR 16.5 24
25.5 24.5 23 -5 25 27
23.5 24.9
PHASE RELATIONSHIP OF N B CAGE AND ABDOMINAL MOTION
Normal 2
Normal 2
MINUTE Pre Test
I 2 3 20.2 degrees 38.8 degees 4 E 1 8 .O degrees 5 0.0 degrees 33.4 degrees 6 0.0 degrees 39.5 degrees
E = unable to determine due to poor quality of data
NO ROLLATOR 0.0 degrees 0.0 degrees 0.0 degrees
ROLLATOR 0.0 degrees 0.0 degrees 26.9 degrees
Normal 3
Normal 4
E = unable to determine due to p o t quality of data
Normal I
II Post Test 1 8.9L 1 9.2L II
MINUTE
6 Minute Average 14.OL 1 13.8L II
Normal 2
Pre Test 1 0.4L 9.0L ,
NO ROLLATOR ROLLATOR
II Post Test 1 3,OL 1 13.4L II
MINUTE Pre Test
NO ROLLATOR 6.8L
ROLLATOR 9.6L
Normal 3
MINUTE Pre Test
Normal 4
I Post Test 6 Minute Average
MINUTE NO ROLLATOR ROLLATOR Pre Test 8.8L 8.2L
NO ROLLATOR 9.3L
Post Test 1 12.9L 1
ROLLATOR E
E = unable to determine due to poor quality of data
12.2L 16.2L
6 Minute Average 1 E 18.8L n
E = unable to detennine due to poor quality of data
15.6L 18.9L
RELATIVE CONTRIBUTION OF RIB CAGE (RC) AND ABDOMEN (A) (RC/A RGTIO)
Normal I iWNUTE NO ROLLATOR 1 ROLLATOR Pre Test 0.62 1.24
1 0.58 1 0.97
6 0.50 O. 72 Post Test 0.77 0.94
II 6 Minute Averaee 1 0.53 1 0.92
Normal 2 11 MINUTE 1 NO ROLLATOR 1 ROLLATOR II
II Post Test 1 1.01 1 0.93 II
Pre Test 1 2 3
1.37 1.35 1.55 1 .O2
1.14 1.70 1.69 1.72
Normal 3
E = unable to detexmine due to poor quality of data
MINUTE Pre Test
Normal 4
NO ROLLATOR 3.28
Post Test 1 3.33 1 3.97 II
ROLLATOR E
MINUTE Pre Test
E = unable to determine due to poor quality of data
NO ROLLATOR ROLLATOR 1.80 1 5.49