Accepted Manuscript The Parallel Walk Test: Its Correlation with Balance and Motor Functions in People with Chronic Stroke Shamay SM. Ng , PhD, Lynn H.L. Chan , BSc (Hons), Cindy S.Y. Chan , BSc (Hons), Stephanie H.Y. Lai , BSc (Hons), Winnie W.Y. Wu , BSc (Hons), Mimi M.Y. Tse , PhD, Shirley S.M. Fong , PhD, Stephanie H.Y. Lai , BSc (Hons), Winnie W.Y. Wu , BSc (Hons), Mimi M.Y. Tse , PhD, Shirley S.M. Fong , PhD PII:
S0003-9993(14)01237-4
DOI:
10.1016/j.apmr.2014.11.002
Reference:
YAPMR 56032
To appear in:
ARCHIVES OF PHYSICAL MEDICINE AND REHABILITATION
Received Date: 15 July 2014 Revised Date:
5 November 2014
Accepted Date: 6 November 2014
Please cite this article as: Ng SS, Chan LHL, Chan CSY, Lai SHY, Wu WWY, Tse MMY, Fong SSM, Lai SHY, Wu WWY, Tse MMY, Fong SSM, The Parallel Walk Test: Its Correlation with Balance and Motor Functions in People with Chronic Stroke, ARCHIVES OF PHYSICAL MEDICINE AND REHABILITATION (2014), doi: 10.1016/j.apmr.2014.11.002. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
1
Running head: Parallel Walk Test in Patients with Stroke
The Parallel Walk Test: Its Correlation with Balance and Motor
RI PT
Functions in People with Chronic Stroke
2
Shamay SM Ng, PhD;1 Lynn H.L. Chan, BSc (Hons);1 Cindy S.Y. Chan, BSc (Hons);1
4 5
Stephanie H.Y. Lai, BSc (Hons);1 Winnie W.Y. Wu, BSc (Hons);1 Mimi M.Y. Tse, PhD;2 Shirley S.M. Fong, PhD3
SC
3
M AN U
6 7 1
8
Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong (SAR), China
9 10 2
11
School of Nursing, The Hong Kong Polytechnic University, Hong Kong (SAR), China
14 15 16 17
3
Institute of Human Performance, The University of Hong Kong, Hong Kong (SAR), China
EP
13
TE D
12
Corresponding and Reprint Address:
19 20 21 22 23 24 25 26 27 28 29
Shamay S.M. Ng, PhD Associate Professor, Department of Rehabilitation Science, The Hong Kong Polytechnic University, Hong Kong (SAR), China. Tel: (852) 2766-4889 Fax: (852) 2330-8656 E-mail: [email protected] No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the authors are associated.
AC C
18
ACCEPTED MANUSCRIPT
30
Declaration of Interest
32
No commercial party having a direct financial interest in the results of the research supporting
33
this article has or will confer a benefit upon the authors or upon any organization with which the
34
authors are associated.
RI PT
31
35
Word counts: 2956 words
SC
36 37
FUNDING
39
This study was supported by General Research Grant (Ref: 562413) from Research Grants
40
Council, Hong Kong to Shamay S. Ng and her team
M AN U
38
41
TE D
42
ACKNOWLEDGEMENT
44
I would like to send my sincere thanks to Mr. David Fong Yat-Fai in assisting subject
45
recruitment and data collection of this project.
AC C
EP
43
1
ACCEPTED MANUSCRIPT
ABSTRACT
1 2
Objectives: To investigate (1) the intra-rater, inter-rater and test-retest reliability of
4
the times and scores generated in the parallel walk test (PWT); (2) their correlations
5
with impairments and activity limitations of individuals with stroke; and (3) the
6
cut-off times that best discriminate individuals with stroke from healthy elderly
7
subjects.
8
Design: Cross sectional study.
9
Setting: University-based rehabilitation center.
M AN U
SC
RI PT
3
Participants: Thirty-seven individuals with stroke and 35 healthy individuals
11
Interventions: Not applicable
12
Main Outcome Measures: The PWT was administered along with the Fugl-Meyer
13
lower extremity assessment (FMA-LE), hand-held dynamometer measurements of
14
ankle dorsiflexor and plantarflexor muscle strength, the 5 times sit-to-stand test
15
(FTSTST), assessment using the Berg Balance Scale (BBS), a limits of stability test
16
(LOS), the 10-meter walk test (10MWT) and the Timed “Up and Go’’ test (TUG).
17
Results: The PWT times and scores showed good to excellent intra-rater, inter-rater
18
and test-retest reliability with individuals with stroke. The PWT times using paths of 3
19
different widths significantly correlated with FMA-LE scores, FTSTS times, BBS
21 22
EP
AC C
20
TE D
10
scores, some LOS results, 10-MWT gait speed and TUG times. PWT times of 6.30 to 7.48 seconds, depending on the path width, were shown reliably to discriminate individuals with stroke from healthy individuals.
23
Conclusion: The PWT is a reliable, easy-to-administer clinical tool for assessing
24
dynamic walking balance in individuals with chronic stroke.
25
Key words: balance, walking; stroke; rehabilitation
26 1
ACCEPTED MANUSCRIPT
27 List of abbreviations: 10-MWT 10-metre walk test
RI PT
AUC Area under the Curve BBS Berg Balance Scale COG Center of Gravity
FTSTST Five-Times-Sit-to-Stand Test
M AN U
ICC Intra-class Correlation Coefficient LOS Limits of Stability Test
ROC Receiver Operating Characteristics RT Reaction Time MVL Maximum Velocity
TE D
MXE Maximum Excursion PWT Parallel Walk Test
AC C
29
EP
TUG Timed “Up and Go” Test 28
SC
FMA-LE Fugl-Meyer Motor Assessment of the Lower Extremities
2
ACCEPTED MANUSCRIPT
30 Impaired balance is common after strokewhich could affect functional activity.1
32
Improving dynamic walking balance is an important goal in stroke rehabilitation.1,2
33
Different types of interventions aimed at improving dynamic walking balance
34
performance.2 However, the commonly used dynamic walking balance tests,
35
including the Dynamic Gait Index,3 Functional Gait Assessment,4 and the Tinetti
36
Performance-Oriented Mobility Assessment5 are generally time-consuming3-5 and/or
37
do not provide a quantitative measure of dynamic walking balance during
38
ambulation.3,5 Clinicians need a more reliable, valid and easy-to-administer tool
39
which properly reflects changes in performance of dynamic walking balance during
40
the rehabilitation process.
M AN U
SC
RI PT
31
The parallel walk test (PWT) was developed to assess dynamic walking balance
42
safely, quickly and simply.6 Subjecst are required to walk between 2 parallel lines 6
43
metres long with 3 different widths (20cm, 30.5cm, 38cm) with their usual gait
44
pattern at a comfortable speed. The times taken to complete the test and the accuracy
45
of foot placement within or outside the lines are recorded as PWT times and PWT
46
scores respectively.
EP
TE D
41
The PWT has been shown to have high degree of test-retest and inter-rater
48
reliability with intra-class correlation coefficients (ICCs) ranging from .63 to .93, with
49 50 51
AC C
47
elderly fallers.7 The PWT times with the 25cm and 30.5cm widths have also been
found to correlate well with the Timed “Up and Go” test scores with older adults.8
However, there has been no study investigating the PWT’s intra-rater, inter-rater and
52
test-retest reliabilities with stroke survivors. In addition, no systematic study of the
53
relationships among PWT times, PWT scores and stroke-specific impairments has
54
been published, nor has any published study established the best cut-off times for
55
discriminating individuals with chronic stroke from healthy older adults. 3
ACCEPTED MANUSCRIPT
The objectives of this study were: (1) to establish the intra-rater, inter-rater and
57
test-retest reliabilities of PWT times and scores with stroke survivors and (2) to
58
investigate the concurrent validity of PWT by exploring any correlation between PWT
59
times and scores and other measures of impairments and activity limitations including:
60
the Fugl-Meyer Lower Extremity Assessment (FMA-LE), lower limb muscle strength,
61
Five Times Sit-to-Stand Test (FTSTST) times, Berg Balance Scale (BBS) scores,
62
limits of stability (LOS), time and speed in the 10-metre walk test (10-mWT), and
63
Timed “Up and Go” test (TUG) times. It was also designed (3) to determine the
64
cut-off PWT times which best discriminate stroke survivors from other healthy elderly
65
subjects.
M AN U
SC
RI PT
56
66
METHODS
67 Subjects
69
This study was a cross-sectional clinical trial. Previous study demonstrated a high
70
degree of inter-rater reliability (ICC range: .93–.99) and test-retest reliability (ICC
71
range: .63–.90) for the PWT times and scores of elderly fallers.7 Assuming ICC values
72
of stroke survivors would be about .90, therequired sample size of 30 was required in
73
order to achieve 90% power to detect an ICC of .90 with a confidence level of .05.
75 76 77
EP
Stroke survivors from local self-help group were included if they (i) were at least
AC C
74
TE D
68
55 years old as incidence of stroke approximately doubles each decade in adults older than age 55 years,9 (ii) had suffered a single stroke at least 1 year previously, (iii) were able to walk 10m with no physical assistance with or without a walking aid, (iv)
78
had an Abbreviated Mental Test10 score of 7 or higher, and (v) had a stable general
79
medical condition. Individuals were excluded if they experienced neurological
80
disorders other than stroke or if they had other co-morbid disability that would hinder
4
ACCEPTED MANUSCRIPT
81
proper assessment. Healthy individuals were recruited from the local community using poster
83
advertising if they were more than 55 years old to serve as controls. Healthy subjects
84
were excluded if they had any conditions that might affect the assessment protocol,
85
such as uncontrolled diabetes mellitus or any neurological or musculoskeletal
86
problems affecting mobility and hindering proper assessment.
RI PT
82
The study was approved by the ethics committee of the Hong Kong Polytechnic
88
University and was conducted according to the guidelines of the Declaration of
89
Helsinki. All the participants were informed about the testing procedures and written
90
consents were obtained prior the start of the study.
91
M AN U
SC
87
Outcome Measurements
93
Parallel Walk Test
94
All subjects were asked to walk at their comfortable walking speed for 6 metres
95
between 3 sets of parallel lines (installed 20cm, 30.5cm and 38cam apart), wearing
96
their usual footwear and with any usual walking aids if required. The time taken to
97
complete each walk was recorded as a PWT time. The PWT scores were calculated
98
based on the accuracy of foot placement. No marks were awarded if the foot
99
placement was always completely between the lines. Stepping on a line earned one
101 102
EP
AC C
100
TE D
92
point, stepping outside the lines or maintaining balance by grasping something scored two points.6Two trials were recorded for each width, with a 2-minute rest between
each trial. The testing order for the different widths was randomized by drawing lots.
103 104
Fugl-Meyer Lower Extremity Assessment
105
The FMA-LE quantifies motor impairment following stroke using 17 items assessing
5
ACCEPTED MANUSCRIPT
the reflexes, movement and coordination. Each item is scored on a 0–2 ordinal scale,
107
adding up to a maximum possible score of 34.11The FMA-LE is well known to have
108
high inter-rater (ICC=.89-.95) and intra-rater reliability (ICC=.96) when used with
109
individuals with chronic stroke.12
RI PT
106
110 Lower limb musclesstrength
112
The muscle strength of the subjects’ ankle dorsiflexors and plantarflexors was
113
measured using a Nicholas hand-held dynamometer (model 01160).aSuch
114
dynamometry has demonstrated high test-retest reliability (ICC=.98)13 and inter-rater
115
reliability (ICC=.91)14 The subjects were positioned in supine lying and were asked to
116
produce a sustained maximum isometric contraction against the examiner’s resistance
117
for 3 seconds. The dynamometer was placed across the mid-shafts of first to fifth
118
metatarsal bones, anteriorly for testing the dorsiflexors and posteriorly for the
119
plantarflexors. Each muscle group was tested 3 times, alternating between the feet and
120
with a 1-minute rest between trials.
TE D
M AN U
SC
111
121
Five-Time-Sit-to-Stand Test
123
The FTSTST measures the functional strength of the lower extremitiesy.15 It has
124
shown excellent intra-rater reliability (ICC=.97–.98), inter-rater realibility (ICC=1.00)
126 127 128
AC C
125
EP
122
and test-retest reliability (ICC=.99-1.00) with chronic stroke subjects.16 The subjects were instructed to stand up fully and sit down in a 43cm high chair with their back against the rest 5 times as fast as possible with their arms crossed over their chest throughout.
129 130
Berg Balance Scale
131
The BBS assesses balance in the performance of 14 functional tasks, rating it on a 6
ACCEPTED MANUSCRIPT
132
5-point scale (0-4), giving a maximum score of 56.17 The assessment has
133
demonstrated excellent intra-rater reliability (ICC=.97) and inter-rater reliability
134
(ICC=.98) with individuals after stroke.17
RI PT
135 Limit of Stability Test
137
A Smart Balance Master systembcan quantify the maximum distance that a person can
138
shift their center of gravity (COG) without losing their balance, stepping or reaching
139
for assistance. A dual force platform detects the position of the COG, displayed as a
140
cursor on an eye-level computer screen.18 It has high test-retest reliabilities
141
(ICC=.78-.91) in measuring the performance of stroke survivors.19,20
142
An overhead harness is worn to ensure the subject’s safety. The system then measures
143
1.
2.
150 151 152 153 154
Maximum Excursion (MXE)(percentage of distance to target) is the maximum distance of COG movement away from the start point in each trial.18
EP
149
3.
10-Metre Walk Test
AC C
148
Movement Velocity (MVL)(degress per second) refers to the average speed of shifting COG towards the target.18
146 147
the time between the start signal and the
TE D
145
Reaction Time (RT)(seconds): subject’s first movement. 18
144
M AN U
SC
136
The 10-MWT is commonly used to measure the gait velocity. Subjects are timed as they walk at their normal speed along a 10-metre walkway with an extra 2 metres for acceleration and deceleration. High test-retest reliability (ICC=.94) has been demonstrated with individuals with chronic stroke.21
155 156
Timed “Up and Go” Test
157
The TUG assesses the functional mobility of frail elderly persons.22 The subject 7
ACCEPTED MANUSCRIPT
158
stands up from a chair, walks 3 metres forward, turns around, walks back and sits
159
down again. The time to complete the test is recorded. The TUG has excellent
160
test-retest reliability (ICC=.95) for individuals with chronic stroke.23
RI PT
161 Testing Procedures
163
To establish the reliability of the PWT, the PWT was conducted on 2 separate days 7
164
to 10 days apart. The PWT times and scores were recorded by two trained raters
165
simultaneously.
SC
162
Apart from the PWT, the stroke subjects completed the FMA-LE, the lower limb
167
muscle strength measurement, FTSTST, BBS, LOS, 10-MWT and TUG in random
168
order to establish the correlations between the PWT and those other assessments. A
169
two-minute rest was given between measurements and between trials to minimize the
170
effect of fatigue. The mean values of the replicate trials were computed for analysis.
171
The healthy controls completed the PWT in one session. Their data were used to
172
determine the cut-off PWT times distinguishing individuals with stroke from healthy
173
individuals.
TE D
M AN U
166
EP
174 Statistical Analysis
176
All the data analysis was done with the help of SPSS software (version 20).c
177 178 179
AC C
175
Intra-class correlation coefficients (ICCs) were computed to measure the intra-rater reliability (ICC3,1), inter-rater reliability (ICC2,2) and test-retest reliability (ICC3,2). The normality of the data and the homogeneity of the variances were checked by
180
applying the Shapiro-Wilk test and Levene’s test. For assessing the between-group
181
differences, independent t-tests were used for the parametric data, and the
182
Mann-Whitney U test was used for those data which were non-parametric.
8
ACCEPTED MANUSCRIPT
Correlations between the results of the PWT and the other assessments were
184
quantified using Pearson’s r if the data were normally distributed and homogeneous;
185
otherwise, Spearmen’s rho was used. Eight primary outcomes were chosen (FMA-LE
186
and BBS scores; RT, MVL and MXE in the LOS test; and 10-MWT, FTSTST and
187
TUGtimes), and the p value for significant correlation was adjusted to .00625 (.05/8)
188
after Bonferroni adjustment. The strength of correlation was classified into little or
189
none (r.75).24
192
SC
Receiver operating characteristics (ROC) curves were plotted to determine the
M AN U
191
RI PT
183
cut-off PWT times best distinguishing stroke survivors from healthy individuals.
193
RESULTS
194
Thirty-seven stroke survivors were recruited (26 males and 11 females; mean age
196
± SD, 62.0 ± 6.2 years; mean years since stroke ± SD, 7.8 ± 3.0). There were
197
thirty-five healthy individuals (11 males and 24 females; mean age ± SD, 64.3 ± 7.8
198
years). Their demographics are summarized in table 1.
TE D
195
The mean PWT times and scores of the stroke group are shown in table 2.
200
Generally, the PWT times increased as the path width decreased, while the PWT
201
scores were smaller with the wider paths. All PWT times and scores show significant
203 204 205
AC C
202
EP
199
differences between different path widths. The stroke group had significantly higher PWT times and scores with all 3 path widths than the healthy controls (p≤.001 in all cases) (table 3). The mean values of all the other outcome measures are shown in table 4.
206 207
Reliability
9
ACCEPTED MANUSCRIPT
The PWT times and scores demonstrated moderate to excellent intra-rater
209
reliabilities with ICCs ranging from .784 to .962 (table 5). Good to excellent
210
inter-rater reliabilities and test-retest reliabilities were found with all 3 walkway
211
widths, with the ICCs ranging from .846 to 1.000 (table 6 and 7).
RI PT
208
212 213
Sensitivity and Specificity
For the 20cm, 30.5 cm and 38 cm path widths the PWT cut-off times were 7.48
215
seconds, 6.30 seconds, and 6.34 seconds respectively (sensitivity: 84–89%, specificity:
216
71–80%, AUC: .885–.894, p≤.001). Details of the AUC analysis are shown in fig 1.
M AN U
SC
214
217 218
Correlation of PWT Times and Scores with Other Outcome Measures The details of the correlations are summarized in table 8. The PWT times with all
220
3 path widths demonstrated significant correlations with the FMA-LE scores,
221
FTSTST times, BBS scores, affected side MXE in the LOS, 10-MWT gait speed, and
222
the TUG times. And with all 3 path widths the PWT scores demonstrated significant
223
correlations with the BBS scores and TUG times.
226 227 228 229 230
EP
225
DISCUSSION
This was the first study designed to investigate the reliabilities and concurrent
AC C
224
TE D
219
validity of the PWT for individuals with stroke. It was also the first to determine the cut-off times best discriminating stroke survivors from healthy elderly individuals.
Reliability of the PWT
231
As Lark’s group found with elderly fallers,7 the PWT times and scores showed
232
good to excellent intra-rater (ICC=.784–.962), inter-rater (ICC=.973–1.000) and
10
ACCEPTED MANUSCRIPT
test–retest (.864–.976) reliabilities.
Detailed testing procedures and the testers’
234
satisfactory adherence to them may have contributed to the high inter-rater reliability,
235
as Ng’s group has demonstrated in their study of the TUG among individuals with
236
stroke.23
RI PT
233
237 238
Performance of the PWT
It is interesting to note that PWT times decreased from Time 1 to Time 2 in
240
walkway with 20cm and 30.5cm path width. Such differences could be potentially
241
attributable to the learning effect of repeated trials. The mean PWT times of the stroke
242
subjects were approximately double the healthy controls with all three walkways in
243
this study (table 3). Stroke-specific impairments including weakness of the lower limb
244
muscles and impaired balance reduce walking speed after stroke.26-27 Such difference
245
increased with a narrower path. Impaired dynamic balance is a typical stroke sequella,
246
and survivors need a wider base of support to maintain their balance while
247
walking.28-29
TE D
M AN U
SC
239
When compared with the published PWT times of elderly fallers,7 our subjects
249
with stroke took 22% - 42.2% longer PWT times, and 29.0% - 64.7 % higher PWT
250
scores. Future studies in recruiting stroke subjects with and without history of falls
251
might help to investigate whether PWT could be used as a screening tool in
253 254 255
AC C
252
EP
248
identifying patients with stroke having high fall risks.
Correlations of PWT Times and Scores with Other Outcome Measures Lower Limb Motor Function
256
In this study, only the PWT times demonstrated meaningful correlations with the
257
FMA-LE scores, but not the PWT scores. The muscle strength and the FMA-LE
258
scores has shown a significant correlation (r=.66) with walking velocity among 11
ACCEPTED MANUSCRIPT
individuals with hemiplegia,30 so the correlation between FMA-LE scores and PWT
260
times is not unexpected. The poor correlation with PWT scores might be explained by
261
the fact that most of the tasks in the FMA-LE are performed lying or sitting rather
262
than upright as in walking.
RI PT
259
It is reasonable that the PWT times showed a significant positive correlation with
264
FTSTST times.The FTSTST measures functional muscle strength, and previous
265
studies have shown that lower limb strength correlates with gait velocity.31-32
SC
263
266 Balance
268
The PWT times and scores correlated with BBS scores. Our results were supported by
269
the fact that significant positive correlations existed between BBS scores and walking
270
speed in patients with stroke.33-34 Stroke survivors walked faster are expected to have
271
better dynamic walking balance performance.
M AN U
267
TE D
272
A larger MXE towards the affected side in the LOS indicates a better ability to
274
maintain balance when shifting center of gravity laterally but those values showed
275
only fair negative correlations with the PWT times. Several reasons might account for
276
this result. Firstly, the MXE was measured with both feet on the Balance Master
277
platform, while lateral stability is challenged during walking in the PWT. Secondly,
279 280
AC C
278
EP
273
an overhead harness was worn to ensure safety during the LOS measurements, but not in the PWT. This may have affected the subjects’ subjective balance confidence.Thirdly, the subjects were required to shift their COG without moving
281
their feet in the LOS testing, while the PWT demands rapid change in the base of
282
support during walking.
283 284
Functional Mobility 12
ACCEPTED MANUSCRIPT
The PWT times with all 3 path widths correlated with gait speed. The results were
286
as expected because both the PWT and 10-MWT times reflect gait velocity.Both
287
PWT times and scores s significant positive correlations with TUG times, as the TUG
288
combines the functional tasks of standing up from sitting, walking forward, and
289
turning. All those functional tasks depend on lower limb muscle strength, balance and
290
walking speed.
RI PT
285
292
SC
291 Cut-off Times and Sensitivity
The PWT times for all 3 widths discriminated well, with the AUC ranging
294
from .885 to .894. The results should be interpreted with caution. Most of the stroke
295
subjects recruited were men (70.3%) while most of the healthy controls were women
296
(68.6%). Previous studies had showed that gender difference existed in muscle
297
strength,35 postural stability,36 and performance of functional tasks.37
M AN U
293
299 300
Study Limitations
TE D
298
This study focused on the time taken to complete the test and the accuracy of foot placement,
302
movements . Also, PWT performance involves multiple determinants, some of which
303
were not measured in this study, such as the base of support and proprioception in the
305 306
AC C
304
but not other compensatory strategies of trunk and upper limb
EP
301
lower limbs.
The results reported here can only be generalized with to subjects fulfilling the
same selection criteria, because of small sample size. Each subject was required to
307
complete six trials when performing the PWT. This may have induced fatigue,
308
learning effects, or both, although the two-minute rest between trials and randomizing
309
the testing order were intended to minimize such problems.
310
This study could not establish any causal relationships among the variables 13
ACCEPTED MANUSCRIPT
because of its cross-sectional design. Our study design was not able to show which
312
walkway width was optimal for assessing dynamic walking balance in patients with
313
stroke. However, a 20 cm walkway width is recommended for assessing dynamic
314
walking balance in stroke rehabilitation, as it occupies the least space and imposes
315
greater challenges on subjects with stroke. Future studies with larger sample sizes
316
having different degree of disabilities are warranted to identify optimal walkway
317
width in PWT for patients with stroke.
318 CONCLUSIONS
M AN U
319
SC
RI PT
311
PWT times and scores show good to excellent intra-rater, inter-rater and test-retest
321
reliabilities with individuals with stroke. The PWT times with all 3 path widths
322
significantly correlated with FMA-LE scores, FTSTST times, BBS score, affected
323
side MXE, 10-MWT gait speed and TUG times. The PWT scores on the 20cm wide
324
path significantly correlated with BBS scores, affected side MXE, 10-MWT gait
325
speed and TUG times.
TE D
320
PWT times can discriminate between individuals with stroke and other healthy
327
elderly persons, with the cut-off times ranging from 6.30 seconds to 7.48 seconds
328
depending on the path width used.
330 331 332
In conclusion, the PWT is a reliable, easy-to-administer clinical tool for assessing
AC C
329
EP
326
dynamic walking balance after stroke. In clinical situations, walkway width of 20 cm, 30.5 cm, or 38 cm will all give reliable results.
333 334
Suppliers
335
a. Lafayette Instrument Company, PO BOX 5729, Lafayette, IN 47903.
336
b. NeuroCom International Inc, 9570 SE Lawnfield Rd, Clackamas, OR 97015. 14
ACCEPTED MANUSCRIPT
337
c. IBM Corp, 1 New Orchard Rd, Armonk, NY 10604-1722.
AC C
EP
TE D
M AN U
SC
RI PT
338
15
ACCEPTED MANUSCRIPT
339 REFERENCES
340
1. Tyson SF, Hanley M, Chillala J, Selley A, Tallis RC. Balance disability after stroke. Phys Ther 2006;86:30-8.
344 345 346
2. Lubetzky-Vilnai A, Kartin D. The effect of balance training on balance performance in individuals poststroke: a systematic review. JNPT 2010; 34:127-137.
367 368 369 370 371 372 373 374 375
SC
M AN U
4. Wrisley DM, Marchetti GF, Kuharsky DK, Whitney SL. Reliability, internal consistency, and validity of data obtained with the functional gait assessment. PhysTher 2004;84:906-18. 5. Tinetti ME. Performance-oriented assessment of mobility problems in elderly patients. J Am GeriatrSoc 1986;34:119-26.
TE D
6. Lark SD, Pasupuleti S. Validity of a functional dynamic walking test for the elderly. Arch Phys Med Rehabil 2009;90:470-4. 7. Lark SD, McCarthy PW, Rowe DA. Reliability of the parallel walk test for the elderly. Arch Phys Med Rehabil 2011;92:812-7.
EP
364 365 366
3. Schumway-Cook A, Woollacott MH. Motor control: theory and practical applications. 4thed. Baltimore: Williams & Wilkins; 1995.
8. Behal K, Bansal A. Correlation between parallel walk test and timed up and go test for assessment of dynamic balance in elderly. Indian J PhysioOcc Therapy 2013;7:6-10.
AC C
347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363
RI PT
341 342 343
9. Feigin VL, Lawes CMM, Bennett DA, Anderson CS. Stroke epidemiology: a review of population-based studies of incidence, prevalence, and case-fatality in the late 20th century. Lancet Neurol 2003;2:43-53. 10. Chu LW, Pei CKW, Ho MH, Chan PT. Validation of the Abbreviated Mental Test (Hong Kong version) in the elderly medical patient. Hong Kong Med J 1995;1:207-11.
16
ACCEPTED MANUSCRIPT
378 379 380 381 382 383
11. Fugl-Meyer AR, JääsköL, Leyman I, Olsson S, Steglind S. The post stroke hemiplegic patient: a method for evaluation of physical performance. Scand J Rehabil Med 1975;7:12-31. 12. Duncan PW, Propst M, Nelson SG. Reliability of the Fugl-Meyer assessment of sensorimotor recovery 1983;63:1606-10.
following
cerebrovascular
accident.
PhysTher
RI PT
376 377
13. Kluding P, Gajewski B. Lower-extremity strength differences predict activity limitations in people with chronic stroke. PhysTher 2009;89:73-81.
387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403
14. Bohannon RW, Andrews AW. Interrater reliability of hand-held dynamometry. PhysTher 1987;67:931-3.
405 406 407 408 409 410 411 412 413
M AN U
15. Csuka M, McCarty DJ. Simple method for measurement of lower extremity muscle strength. Am J Med 1985;78:77-81. 16. Mong Y, Teo TW, Ng SS. 5-repetition sit-to-stand test in subjects with chronic stroke: reliability and validity. Arch Phys Med Rehab 2010;91:401-3.
TE D
17. Berg K, Wood-Dauphinee S, Williams JI. The balance scale: reliability assessment with elderly residents and patients with an acute stroke. Scand J Rehabil Med 1995;27:27-36.
EP
18. NeuroCom InternationalInc: Balance Master operator’s manual. Clackamas: NeuroCom International Inc; 2002. 19. Liston RA, Brouwer BJ. Reliability and validity of measures obtained from stroke patients using the Balance Master. Arch Phys Med Rehabil 1996;77:425-30.
AC C
404
SC
384 385 386
20. Chien CW, Hu MH, Tang PF, Sheu CF, Hsieh CL. A comparison of psychometric properties of the Smart Balance Master system and the postural assessment scale for stroke in people who have had mild stroke. Arch Phys Med Rehabil 2007;88:374-80. 21. Flansbjer UB, Holmbäck AM, Downham D, Patten C, Lexell J. Reliability of gait performance tests in men and women with hemiparesis after stroke. J Rehabil Med 2005;37:75-82. 17
ACCEPTED MANUSCRIPT
414 415 416 417 418
22. Podsiadlo D, Richardson S. The timed “Up & Go”: A test of basic functional mobility for frail elderly persons. J Am GeriatrSoc 1991;39:142-8. 23. Ng SS, Hui-Chan CW. The timed up & go test: Its reliability and association with lower-limb impairments and locomotor capacities in people with chronic stroke. Arch Phys Med Rehab 2005;86:1641-7.
422 423 424
24. Portney LG, Watkins MP. Foundations of clinical research: applications to practice. 3rd ed. Upper Saddle River, NJ: Prentice Hall; 2007.
425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441
25. Zweig MH, Campbell G. Receiver-operating characteristic (ROC) plots: A fundamental evaluation tool in clinical medicine. ClinChem 1993;39:561-77.
442
30. Dettmann MA, Linder MT, Sepic SB. Relationships among walking performance,
SC
M AN U
26. Wing K, Lynskey JV, Bosch PR. Walking speed in stroke survivors: considerations for clinical practice. Topics Geriatric Rehab 2012;28:113-21.
TE D
27. Carvalho C, Sunnerhagen KS, Willén C. Walking performance and muscle strength in the later stage poststroke: a nonlinear relationship. Arch Phys Med Rehab 2013;94:845-50. 28. Harris J, Eng J, Marigold D, Tokuno CD, Louis CL. Relationship of balance and mobility to fall incidence in people with chronic stroke. PhysTher 2005;85:150-8.
EP
29. de Oliveira CB, de Medeiros ÍRT, Frota NAF, Greters ME, Conforto AB. Balance control in hemiparetic stroke patients: main tools for evaluation. J Rehab Res Dev 2008;45:1215-26.
AC C
443 444 445 446 447 448 449 450 451
RI PT
419 420 421
postural stability, and functional assessments of the hemiplegic patient. Am J Phys Med 1987;66:77-90.
31. Nakamura R, Watanabe S, Handa T, Morohashi I. The relationship between walking speed and muscle strength for knee extension in hemiparetic stroke patients: a follow-up study. Tohoku J Exp Med 1988;154:111-3. 32. Nadeau S, Gravel D, Arsenault AB, Bourbonnais D. Plantarflexor weakness as a limiting factor of gait speed in stroke subjects and the compensating role of hip 18
ACCEPTED MANUSCRIPT
452 453
33. Blum L, Korner-Bitensky N. Usefulness of the Berg Balance Scale in stroke rehabilitation: a systematic review. Phys Ther 2008;88:559-66.
454 455 456
34. Kobayashi T, Leung AK, Akazawa Y, Hutchins SW. Correlations between Berg balance scale and gait speed in individuals with stroke wearing ankle-foot
480 481 482 483 484 485 486 487 488 489
RI PT
SC
strength and muscle fiber characteristics. Eur J Appl Physiol Occup Physiol 1993;66:254–62
M AN U
36. Masui T, Hasegawa Y, Matsuyama Y, Sakano S, Kawasaki M, Suzuki S. Gender differences in platform measures of balance in rural community-dwelling elders. Arch Gerontol Geriatr 2005;41:201-9. 37. Butler AA, Menant JC, Tiedemann AC, Lord SR. Age and gender differences in seven tests of functional mobility. J Neuroeng Rehabil 2009;6:31-9
TE D
463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479
35. Miller AE, MacDougall JD, Tarnopolsky MA, Sale DG. Gender differences in
EP
460 461 462
orthoses - a pilot study. Disabil Rehabil Assist Technol 2014;23:1-4.
AC C
457 458 459
19
ACCEPTED MANUSCRIPT
490 491
Figure Legend
492 Fig 1. Receiver operating characteristic curves. A. ROC curve for PWT Time (Path
494
width = 20cm) between healthy individuals and individuals with stroke (AUC=.885;
495
sensitivity=84%; specificity=80%). B. ROC curve for PWT Time (Path width =
496
30.5cm) between healthy individuals and individuals with stroke (AUC=.891;
497
sensitivity=89%; specificity=71%). C. ROC curves for PWT Time (Path width =
498
38cm) between healthy individuals and individuals with stroke (AUC=.894;
499
sensitivity=87%; specificity=74%)
M AN U
SC
RI PT
493
AC C
EP
TE D
500
20
ACCEPTED MANUSCRIPT
Table 1 Demographics of the 2 Subject Groups Stroke (n=37)
Healthy (n=35)
p
Age (y)
62.0 ± 6.2
64.3 ± 7.8
.172
Sex (M/F)
26/11
11/24
.001*
Height (cm)
164.1 ± 7.7
160.6 ± 9.2
.086
67.5 ± 9.0
58.5 ± 10.9
Body mass index (kg/m )
25.1 ± 2.7
22.6 ± 3.7
Years since stroke
7.8 ± 3.0
NA
Weight (kg) 2
RI PT
Descriptor
SC M AN U TE D EP AC C
S0003-9993(14)01237-4
DOI:
10.1016/j.apmr.2014.11.002
Reference:
YAPMR 56032
To appear in:
ARCHIVES OF PHYSICAL MEDICINE AND REHABILITATION
Received Date: 15 July 2014 Revised Date:
5 November 2014
Accepted Date: 6 November 2014
Please cite this article as: Ng SS, Chan LHL, Chan CSY, Lai SHY, Wu WWY, Tse MMY, Fong SSM, Lai SHY, Wu WWY, Tse MMY, Fong SSM, The Parallel Walk Test: Its Correlation with Balance and Motor Functions in People with Chronic Stroke, ARCHIVES OF PHYSICAL MEDICINE AND REHABILITATION (2014), doi: 10.1016/j.apmr.2014.11.002. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
1
Running head: Parallel Walk Test in Patients with Stroke
The Parallel Walk Test: Its Correlation with Balance and Motor
RI PT
Functions in People with Chronic Stroke
2
Shamay SM Ng, PhD;1 Lynn H.L. Chan, BSc (Hons);1 Cindy S.Y. Chan, BSc (Hons);1
4 5
Stephanie H.Y. Lai, BSc (Hons);1 Winnie W.Y. Wu, BSc (Hons);1 Mimi M.Y. Tse, PhD;2 Shirley S.M. Fong, PhD3
SC
3
M AN U
6 7 1
8
Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong (SAR), China
9 10 2
11
School of Nursing, The Hong Kong Polytechnic University, Hong Kong (SAR), China
14 15 16 17
3
Institute of Human Performance, The University of Hong Kong, Hong Kong (SAR), China
EP
13
TE D
12
Corresponding and Reprint Address:
19 20 21 22 23 24 25 26 27 28 29
Shamay S.M. Ng, PhD Associate Professor, Department of Rehabilitation Science, The Hong Kong Polytechnic University, Hong Kong (SAR), China. Tel: (852) 2766-4889 Fax: (852) 2330-8656 E-mail: [email protected] No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the authors are associated.
AC C
18
ACCEPTED MANUSCRIPT
30
Declaration of Interest
32
No commercial party having a direct financial interest in the results of the research supporting
33
this article has or will confer a benefit upon the authors or upon any organization with which the
34
authors are associated.
RI PT
31
35
Word counts: 2956 words
SC
36 37
FUNDING
39
This study was supported by General Research Grant (Ref: 562413) from Research Grants
40
Council, Hong Kong to Shamay S. Ng and her team
M AN U
38
41
TE D
42
ACKNOWLEDGEMENT
44
I would like to send my sincere thanks to Mr. David Fong Yat-Fai in assisting subject
45
recruitment and data collection of this project.
AC C
EP
43
1
ACCEPTED MANUSCRIPT
ABSTRACT
1 2
Objectives: To investigate (1) the intra-rater, inter-rater and test-retest reliability of
4
the times and scores generated in the parallel walk test (PWT); (2) their correlations
5
with impairments and activity limitations of individuals with stroke; and (3) the
6
cut-off times that best discriminate individuals with stroke from healthy elderly
7
subjects.
8
Design: Cross sectional study.
9
Setting: University-based rehabilitation center.
M AN U
SC
RI PT
3
Participants: Thirty-seven individuals with stroke and 35 healthy individuals
11
Interventions: Not applicable
12
Main Outcome Measures: The PWT was administered along with the Fugl-Meyer
13
lower extremity assessment (FMA-LE), hand-held dynamometer measurements of
14
ankle dorsiflexor and plantarflexor muscle strength, the 5 times sit-to-stand test
15
(FTSTST), assessment using the Berg Balance Scale (BBS), a limits of stability test
16
(LOS), the 10-meter walk test (10MWT) and the Timed “Up and Go’’ test (TUG).
17
Results: The PWT times and scores showed good to excellent intra-rater, inter-rater
18
and test-retest reliability with individuals with stroke. The PWT times using paths of 3
19
different widths significantly correlated with FMA-LE scores, FTSTS times, BBS
21 22
EP
AC C
20
TE D
10
scores, some LOS results, 10-MWT gait speed and TUG times. PWT times of 6.30 to 7.48 seconds, depending on the path width, were shown reliably to discriminate individuals with stroke from healthy individuals.
23
Conclusion: The PWT is a reliable, easy-to-administer clinical tool for assessing
24
dynamic walking balance in individuals with chronic stroke.
25
Key words: balance, walking; stroke; rehabilitation
26 1
ACCEPTED MANUSCRIPT
27 List of abbreviations: 10-MWT 10-metre walk test
RI PT
AUC Area under the Curve BBS Berg Balance Scale COG Center of Gravity
FTSTST Five-Times-Sit-to-Stand Test
M AN U
ICC Intra-class Correlation Coefficient LOS Limits of Stability Test
ROC Receiver Operating Characteristics RT Reaction Time MVL Maximum Velocity
TE D
MXE Maximum Excursion PWT Parallel Walk Test
AC C
29
EP
TUG Timed “Up and Go” Test 28
SC
FMA-LE Fugl-Meyer Motor Assessment of the Lower Extremities
2
ACCEPTED MANUSCRIPT
30 Impaired balance is common after strokewhich could affect functional activity.1
32
Improving dynamic walking balance is an important goal in stroke rehabilitation.1,2
33
Different types of interventions aimed at improving dynamic walking balance
34
performance.2 However, the commonly used dynamic walking balance tests,
35
including the Dynamic Gait Index,3 Functional Gait Assessment,4 and the Tinetti
36
Performance-Oriented Mobility Assessment5 are generally time-consuming3-5 and/or
37
do not provide a quantitative measure of dynamic walking balance during
38
ambulation.3,5 Clinicians need a more reliable, valid and easy-to-administer tool
39
which properly reflects changes in performance of dynamic walking balance during
40
the rehabilitation process.
M AN U
SC
RI PT
31
The parallel walk test (PWT) was developed to assess dynamic walking balance
42
safely, quickly and simply.6 Subjecst are required to walk between 2 parallel lines 6
43
metres long with 3 different widths (20cm, 30.5cm, 38cm) with their usual gait
44
pattern at a comfortable speed. The times taken to complete the test and the accuracy
45
of foot placement within or outside the lines are recorded as PWT times and PWT
46
scores respectively.
EP
TE D
41
The PWT has been shown to have high degree of test-retest and inter-rater
48
reliability with intra-class correlation coefficients (ICCs) ranging from .63 to .93, with
49 50 51
AC C
47
elderly fallers.7 The PWT times with the 25cm and 30.5cm widths have also been
found to correlate well with the Timed “Up and Go” test scores with older adults.8
However, there has been no study investigating the PWT’s intra-rater, inter-rater and
52
test-retest reliabilities with stroke survivors. In addition, no systematic study of the
53
relationships among PWT times, PWT scores and stroke-specific impairments has
54
been published, nor has any published study established the best cut-off times for
55
discriminating individuals with chronic stroke from healthy older adults. 3
ACCEPTED MANUSCRIPT
The objectives of this study were: (1) to establish the intra-rater, inter-rater and
57
test-retest reliabilities of PWT times and scores with stroke survivors and (2) to
58
investigate the concurrent validity of PWT by exploring any correlation between PWT
59
times and scores and other measures of impairments and activity limitations including:
60
the Fugl-Meyer Lower Extremity Assessment (FMA-LE), lower limb muscle strength,
61
Five Times Sit-to-Stand Test (FTSTST) times, Berg Balance Scale (BBS) scores,
62
limits of stability (LOS), time and speed in the 10-metre walk test (10-mWT), and
63
Timed “Up and Go” test (TUG) times. It was also designed (3) to determine the
64
cut-off PWT times which best discriminate stroke survivors from other healthy elderly
65
subjects.
M AN U
SC
RI PT
56
66
METHODS
67 Subjects
69
This study was a cross-sectional clinical trial. Previous study demonstrated a high
70
degree of inter-rater reliability (ICC range: .93–.99) and test-retest reliability (ICC
71
range: .63–.90) for the PWT times and scores of elderly fallers.7 Assuming ICC values
72
of stroke survivors would be about .90, therequired sample size of 30 was required in
73
order to achieve 90% power to detect an ICC of .90 with a confidence level of .05.
75 76 77
EP
Stroke survivors from local self-help group were included if they (i) were at least
AC C
74
TE D
68
55 years old as incidence of stroke approximately doubles each decade in adults older than age 55 years,9 (ii) had suffered a single stroke at least 1 year previously, (iii) were able to walk 10m with no physical assistance with or without a walking aid, (iv)
78
had an Abbreviated Mental Test10 score of 7 or higher, and (v) had a stable general
79
medical condition. Individuals were excluded if they experienced neurological
80
disorders other than stroke or if they had other co-morbid disability that would hinder
4
ACCEPTED MANUSCRIPT
81
proper assessment. Healthy individuals were recruited from the local community using poster
83
advertising if they were more than 55 years old to serve as controls. Healthy subjects
84
were excluded if they had any conditions that might affect the assessment protocol,
85
such as uncontrolled diabetes mellitus or any neurological or musculoskeletal
86
problems affecting mobility and hindering proper assessment.
RI PT
82
The study was approved by the ethics committee of the Hong Kong Polytechnic
88
University and was conducted according to the guidelines of the Declaration of
89
Helsinki. All the participants were informed about the testing procedures and written
90
consents were obtained prior the start of the study.
91
M AN U
SC
87
Outcome Measurements
93
Parallel Walk Test
94
All subjects were asked to walk at their comfortable walking speed for 6 metres
95
between 3 sets of parallel lines (installed 20cm, 30.5cm and 38cam apart), wearing
96
their usual footwear and with any usual walking aids if required. The time taken to
97
complete each walk was recorded as a PWT time. The PWT scores were calculated
98
based on the accuracy of foot placement. No marks were awarded if the foot
99
placement was always completely between the lines. Stepping on a line earned one
101 102
EP
AC C
100
TE D
92
point, stepping outside the lines or maintaining balance by grasping something scored two points.6Two trials were recorded for each width, with a 2-minute rest between
each trial. The testing order for the different widths was randomized by drawing lots.
103 104
Fugl-Meyer Lower Extremity Assessment
105
The FMA-LE quantifies motor impairment following stroke using 17 items assessing
5
ACCEPTED MANUSCRIPT
the reflexes, movement and coordination. Each item is scored on a 0–2 ordinal scale,
107
adding up to a maximum possible score of 34.11The FMA-LE is well known to have
108
high inter-rater (ICC=.89-.95) and intra-rater reliability (ICC=.96) when used with
109
individuals with chronic stroke.12
RI PT
106
110 Lower limb musclesstrength
112
The muscle strength of the subjects’ ankle dorsiflexors and plantarflexors was
113
measured using a Nicholas hand-held dynamometer (model 01160).aSuch
114
dynamometry has demonstrated high test-retest reliability (ICC=.98)13 and inter-rater
115
reliability (ICC=.91)14 The subjects were positioned in supine lying and were asked to
116
produce a sustained maximum isometric contraction against the examiner’s resistance
117
for 3 seconds. The dynamometer was placed across the mid-shafts of first to fifth
118
metatarsal bones, anteriorly for testing the dorsiflexors and posteriorly for the
119
plantarflexors. Each muscle group was tested 3 times, alternating between the feet and
120
with a 1-minute rest between trials.
TE D
M AN U
SC
111
121
Five-Time-Sit-to-Stand Test
123
The FTSTST measures the functional strength of the lower extremitiesy.15 It has
124
shown excellent intra-rater reliability (ICC=.97–.98), inter-rater realibility (ICC=1.00)
126 127 128
AC C
125
EP
122
and test-retest reliability (ICC=.99-1.00) with chronic stroke subjects.16 The subjects were instructed to stand up fully and sit down in a 43cm high chair with their back against the rest 5 times as fast as possible with their arms crossed over their chest throughout.
129 130
Berg Balance Scale
131
The BBS assesses balance in the performance of 14 functional tasks, rating it on a 6
ACCEPTED MANUSCRIPT
132
5-point scale (0-4), giving a maximum score of 56.17 The assessment has
133
demonstrated excellent intra-rater reliability (ICC=.97) and inter-rater reliability
134
(ICC=.98) with individuals after stroke.17
RI PT
135 Limit of Stability Test
137
A Smart Balance Master systembcan quantify the maximum distance that a person can
138
shift their center of gravity (COG) without losing their balance, stepping or reaching
139
for assistance. A dual force platform detects the position of the COG, displayed as a
140
cursor on an eye-level computer screen.18 It has high test-retest reliabilities
141
(ICC=.78-.91) in measuring the performance of stroke survivors.19,20
142
An overhead harness is worn to ensure the subject’s safety. The system then measures
143
1.
2.
150 151 152 153 154
Maximum Excursion (MXE)(percentage of distance to target) is the maximum distance of COG movement away from the start point in each trial.18
EP
149
3.
10-Metre Walk Test
AC C
148
Movement Velocity (MVL)(degress per second) refers to the average speed of shifting COG towards the target.18
146 147
the time between the start signal and the
TE D
145
Reaction Time (RT)(seconds): subject’s first movement. 18
144
M AN U
SC
136
The 10-MWT is commonly used to measure the gait velocity. Subjects are timed as they walk at their normal speed along a 10-metre walkway with an extra 2 metres for acceleration and deceleration. High test-retest reliability (ICC=.94) has been demonstrated with individuals with chronic stroke.21
155 156
Timed “Up and Go” Test
157
The TUG assesses the functional mobility of frail elderly persons.22 The subject 7
ACCEPTED MANUSCRIPT
158
stands up from a chair, walks 3 metres forward, turns around, walks back and sits
159
down again. The time to complete the test is recorded. The TUG has excellent
160
test-retest reliability (ICC=.95) for individuals with chronic stroke.23
RI PT
161 Testing Procedures
163
To establish the reliability of the PWT, the PWT was conducted on 2 separate days 7
164
to 10 days apart. The PWT times and scores were recorded by two trained raters
165
simultaneously.
SC
162
Apart from the PWT, the stroke subjects completed the FMA-LE, the lower limb
167
muscle strength measurement, FTSTST, BBS, LOS, 10-MWT and TUG in random
168
order to establish the correlations between the PWT and those other assessments. A
169
two-minute rest was given between measurements and between trials to minimize the
170
effect of fatigue. The mean values of the replicate trials were computed for analysis.
171
The healthy controls completed the PWT in one session. Their data were used to
172
determine the cut-off PWT times distinguishing individuals with stroke from healthy
173
individuals.
TE D
M AN U
166
EP
174 Statistical Analysis
176
All the data analysis was done with the help of SPSS software (version 20).c
177 178 179
AC C
175
Intra-class correlation coefficients (ICCs) were computed to measure the intra-rater reliability (ICC3,1), inter-rater reliability (ICC2,2) and test-retest reliability (ICC3,2). The normality of the data and the homogeneity of the variances were checked by
180
applying the Shapiro-Wilk test and Levene’s test. For assessing the between-group
181
differences, independent t-tests were used for the parametric data, and the
182
Mann-Whitney U test was used for those data which were non-parametric.
8
ACCEPTED MANUSCRIPT
Correlations between the results of the PWT and the other assessments were
184
quantified using Pearson’s r if the data were normally distributed and homogeneous;
185
otherwise, Spearmen’s rho was used. Eight primary outcomes were chosen (FMA-LE
186
and BBS scores; RT, MVL and MXE in the LOS test; and 10-MWT, FTSTST and
187
TUGtimes), and the p value for significant correlation was adjusted to .00625 (.05/8)
188
after Bonferroni adjustment. The strength of correlation was classified into little or
189
none (r.75).24
192
SC
Receiver operating characteristics (ROC) curves were plotted to determine the
M AN U
191
RI PT
183
cut-off PWT times best distinguishing stroke survivors from healthy individuals.
193
RESULTS
194
Thirty-seven stroke survivors were recruited (26 males and 11 females; mean age
196
± SD, 62.0 ± 6.2 years; mean years since stroke ± SD, 7.8 ± 3.0). There were
197
thirty-five healthy individuals (11 males and 24 females; mean age ± SD, 64.3 ± 7.8
198
years). Their demographics are summarized in table 1.
TE D
195
The mean PWT times and scores of the stroke group are shown in table 2.
200
Generally, the PWT times increased as the path width decreased, while the PWT
201
scores were smaller with the wider paths. All PWT times and scores show significant
203 204 205
AC C
202
EP
199
differences between different path widths. The stroke group had significantly higher PWT times and scores with all 3 path widths than the healthy controls (p≤.001 in all cases) (table 3). The mean values of all the other outcome measures are shown in table 4.
206 207
Reliability
9
ACCEPTED MANUSCRIPT
The PWT times and scores demonstrated moderate to excellent intra-rater
209
reliabilities with ICCs ranging from .784 to .962 (table 5). Good to excellent
210
inter-rater reliabilities and test-retest reliabilities were found with all 3 walkway
211
widths, with the ICCs ranging from .846 to 1.000 (table 6 and 7).
RI PT
208
212 213
Sensitivity and Specificity
For the 20cm, 30.5 cm and 38 cm path widths the PWT cut-off times were 7.48
215
seconds, 6.30 seconds, and 6.34 seconds respectively (sensitivity: 84–89%, specificity:
216
71–80%, AUC: .885–.894, p≤.001). Details of the AUC analysis are shown in fig 1.
M AN U
SC
214
217 218
Correlation of PWT Times and Scores with Other Outcome Measures The details of the correlations are summarized in table 8. The PWT times with all
220
3 path widths demonstrated significant correlations with the FMA-LE scores,
221
FTSTST times, BBS scores, affected side MXE in the LOS, 10-MWT gait speed, and
222
the TUG times. And with all 3 path widths the PWT scores demonstrated significant
223
correlations with the BBS scores and TUG times.
226 227 228 229 230
EP
225
DISCUSSION
This was the first study designed to investigate the reliabilities and concurrent
AC C
224
TE D
219
validity of the PWT for individuals with stroke. It was also the first to determine the cut-off times best discriminating stroke survivors from healthy elderly individuals.
Reliability of the PWT
231
As Lark’s group found with elderly fallers,7 the PWT times and scores showed
232
good to excellent intra-rater (ICC=.784–.962), inter-rater (ICC=.973–1.000) and
10
ACCEPTED MANUSCRIPT
test–retest (.864–.976) reliabilities.
Detailed testing procedures and the testers’
234
satisfactory adherence to them may have contributed to the high inter-rater reliability,
235
as Ng’s group has demonstrated in their study of the TUG among individuals with
236
stroke.23
RI PT
233
237 238
Performance of the PWT
It is interesting to note that PWT times decreased from Time 1 to Time 2 in
240
walkway with 20cm and 30.5cm path width. Such differences could be potentially
241
attributable to the learning effect of repeated trials. The mean PWT times of the stroke
242
subjects were approximately double the healthy controls with all three walkways in
243
this study (table 3). Stroke-specific impairments including weakness of the lower limb
244
muscles and impaired balance reduce walking speed after stroke.26-27 Such difference
245
increased with a narrower path. Impaired dynamic balance is a typical stroke sequella,
246
and survivors need a wider base of support to maintain their balance while
247
walking.28-29
TE D
M AN U
SC
239
When compared with the published PWT times of elderly fallers,7 our subjects
249
with stroke took 22% - 42.2% longer PWT times, and 29.0% - 64.7 % higher PWT
250
scores. Future studies in recruiting stroke subjects with and without history of falls
251
might help to investigate whether PWT could be used as a screening tool in
253 254 255
AC C
252
EP
248
identifying patients with stroke having high fall risks.
Correlations of PWT Times and Scores with Other Outcome Measures Lower Limb Motor Function
256
In this study, only the PWT times demonstrated meaningful correlations with the
257
FMA-LE scores, but not the PWT scores. The muscle strength and the FMA-LE
258
scores has shown a significant correlation (r=.66) with walking velocity among 11
ACCEPTED MANUSCRIPT
individuals with hemiplegia,30 so the correlation between FMA-LE scores and PWT
260
times is not unexpected. The poor correlation with PWT scores might be explained by
261
the fact that most of the tasks in the FMA-LE are performed lying or sitting rather
262
than upright as in walking.
RI PT
259
It is reasonable that the PWT times showed a significant positive correlation with
264
FTSTST times.The FTSTST measures functional muscle strength, and previous
265
studies have shown that lower limb strength correlates with gait velocity.31-32
SC
263
266 Balance
268
The PWT times and scores correlated with BBS scores. Our results were supported by
269
the fact that significant positive correlations existed between BBS scores and walking
270
speed in patients with stroke.33-34 Stroke survivors walked faster are expected to have
271
better dynamic walking balance performance.
M AN U
267
TE D
272
A larger MXE towards the affected side in the LOS indicates a better ability to
274
maintain balance when shifting center of gravity laterally but those values showed
275
only fair negative correlations with the PWT times. Several reasons might account for
276
this result. Firstly, the MXE was measured with both feet on the Balance Master
277
platform, while lateral stability is challenged during walking in the PWT. Secondly,
279 280
AC C
278
EP
273
an overhead harness was worn to ensure safety during the LOS measurements, but not in the PWT. This may have affected the subjects’ subjective balance confidence.Thirdly, the subjects were required to shift their COG without moving
281
their feet in the LOS testing, while the PWT demands rapid change in the base of
282
support during walking.
283 284
Functional Mobility 12
ACCEPTED MANUSCRIPT
The PWT times with all 3 path widths correlated with gait speed. The results were
286
as expected because both the PWT and 10-MWT times reflect gait velocity.Both
287
PWT times and scores s significant positive correlations with TUG times, as the TUG
288
combines the functional tasks of standing up from sitting, walking forward, and
289
turning. All those functional tasks depend on lower limb muscle strength, balance and
290
walking speed.
RI PT
285
292
SC
291 Cut-off Times and Sensitivity
The PWT times for all 3 widths discriminated well, with the AUC ranging
294
from .885 to .894. The results should be interpreted with caution. Most of the stroke
295
subjects recruited were men (70.3%) while most of the healthy controls were women
296
(68.6%). Previous studies had showed that gender difference existed in muscle
297
strength,35 postural stability,36 and performance of functional tasks.37
M AN U
293
299 300
Study Limitations
TE D
298
This study focused on the time taken to complete the test and the accuracy of foot placement,
302
movements . Also, PWT performance involves multiple determinants, some of which
303
were not measured in this study, such as the base of support and proprioception in the
305 306
AC C
304
but not other compensatory strategies of trunk and upper limb
EP
301
lower limbs.
The results reported here can only be generalized with to subjects fulfilling the
same selection criteria, because of small sample size. Each subject was required to
307
complete six trials when performing the PWT. This may have induced fatigue,
308
learning effects, or both, although the two-minute rest between trials and randomizing
309
the testing order were intended to minimize such problems.
310
This study could not establish any causal relationships among the variables 13
ACCEPTED MANUSCRIPT
because of its cross-sectional design. Our study design was not able to show which
312
walkway width was optimal for assessing dynamic walking balance in patients with
313
stroke. However, a 20 cm walkway width is recommended for assessing dynamic
314
walking balance in stroke rehabilitation, as it occupies the least space and imposes
315
greater challenges on subjects with stroke. Future studies with larger sample sizes
316
having different degree of disabilities are warranted to identify optimal walkway
317
width in PWT for patients with stroke.
318 CONCLUSIONS
M AN U
319
SC
RI PT
311
PWT times and scores show good to excellent intra-rater, inter-rater and test-retest
321
reliabilities with individuals with stroke. The PWT times with all 3 path widths
322
significantly correlated with FMA-LE scores, FTSTST times, BBS score, affected
323
side MXE, 10-MWT gait speed and TUG times. The PWT scores on the 20cm wide
324
path significantly correlated with BBS scores, affected side MXE, 10-MWT gait
325
speed and TUG times.
TE D
320
PWT times can discriminate between individuals with stroke and other healthy
327
elderly persons, with the cut-off times ranging from 6.30 seconds to 7.48 seconds
328
depending on the path width used.
330 331 332
In conclusion, the PWT is a reliable, easy-to-administer clinical tool for assessing
AC C
329
EP
326
dynamic walking balance after stroke. In clinical situations, walkway width of 20 cm, 30.5 cm, or 38 cm will all give reliable results.
333 334
Suppliers
335
a. Lafayette Instrument Company, PO BOX 5729, Lafayette, IN 47903.
336
b. NeuroCom International Inc, 9570 SE Lawnfield Rd, Clackamas, OR 97015. 14
ACCEPTED MANUSCRIPT
337
c. IBM Corp, 1 New Orchard Rd, Armonk, NY 10604-1722.
AC C
EP
TE D
M AN U
SC
RI PT
338
15
ACCEPTED MANUSCRIPT
339 REFERENCES
340
1. Tyson SF, Hanley M, Chillala J, Selley A, Tallis RC. Balance disability after stroke. Phys Ther 2006;86:30-8.
344 345 346
2. Lubetzky-Vilnai A, Kartin D. The effect of balance training on balance performance in individuals poststroke: a systematic review. JNPT 2010; 34:127-137.
367 368 369 370 371 372 373 374 375
SC
M AN U
4. Wrisley DM, Marchetti GF, Kuharsky DK, Whitney SL. Reliability, internal consistency, and validity of data obtained with the functional gait assessment. PhysTher 2004;84:906-18. 5. Tinetti ME. Performance-oriented assessment of mobility problems in elderly patients. J Am GeriatrSoc 1986;34:119-26.
TE D
6. Lark SD, Pasupuleti S. Validity of a functional dynamic walking test for the elderly. Arch Phys Med Rehabil 2009;90:470-4. 7. Lark SD, McCarthy PW, Rowe DA. Reliability of the parallel walk test for the elderly. Arch Phys Med Rehabil 2011;92:812-7.
EP
364 365 366
3. Schumway-Cook A, Woollacott MH. Motor control: theory and practical applications. 4thed. Baltimore: Williams & Wilkins; 1995.
8. Behal K, Bansal A. Correlation between parallel walk test and timed up and go test for assessment of dynamic balance in elderly. Indian J PhysioOcc Therapy 2013;7:6-10.
AC C
347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363
RI PT
341 342 343
9. Feigin VL, Lawes CMM, Bennett DA, Anderson CS. Stroke epidemiology: a review of population-based studies of incidence, prevalence, and case-fatality in the late 20th century. Lancet Neurol 2003;2:43-53. 10. Chu LW, Pei CKW, Ho MH, Chan PT. Validation of the Abbreviated Mental Test (Hong Kong version) in the elderly medical patient. Hong Kong Med J 1995;1:207-11.
16
ACCEPTED MANUSCRIPT
378 379 380 381 382 383
11. Fugl-Meyer AR, JääsköL, Leyman I, Olsson S, Steglind S. The post stroke hemiplegic patient: a method for evaluation of physical performance. Scand J Rehabil Med 1975;7:12-31. 12. Duncan PW, Propst M, Nelson SG. Reliability of the Fugl-Meyer assessment of sensorimotor recovery 1983;63:1606-10.
following
cerebrovascular
accident.
PhysTher
RI PT
376 377
13. Kluding P, Gajewski B. Lower-extremity strength differences predict activity limitations in people with chronic stroke. PhysTher 2009;89:73-81.
387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403
14. Bohannon RW, Andrews AW. Interrater reliability of hand-held dynamometry. PhysTher 1987;67:931-3.
405 406 407 408 409 410 411 412 413
M AN U
15. Csuka M, McCarty DJ. Simple method for measurement of lower extremity muscle strength. Am J Med 1985;78:77-81. 16. Mong Y, Teo TW, Ng SS. 5-repetition sit-to-stand test in subjects with chronic stroke: reliability and validity. Arch Phys Med Rehab 2010;91:401-3.
TE D
17. Berg K, Wood-Dauphinee S, Williams JI. The balance scale: reliability assessment with elderly residents and patients with an acute stroke. Scand J Rehabil Med 1995;27:27-36.
EP
18. NeuroCom InternationalInc: Balance Master operator’s manual. Clackamas: NeuroCom International Inc; 2002. 19. Liston RA, Brouwer BJ. Reliability and validity of measures obtained from stroke patients using the Balance Master. Arch Phys Med Rehabil 1996;77:425-30.
AC C
404
SC
384 385 386
20. Chien CW, Hu MH, Tang PF, Sheu CF, Hsieh CL. A comparison of psychometric properties of the Smart Balance Master system and the postural assessment scale for stroke in people who have had mild stroke. Arch Phys Med Rehabil 2007;88:374-80. 21. Flansbjer UB, Holmbäck AM, Downham D, Patten C, Lexell J. Reliability of gait performance tests in men and women with hemiparesis after stroke. J Rehabil Med 2005;37:75-82. 17
ACCEPTED MANUSCRIPT
414 415 416 417 418
22. Podsiadlo D, Richardson S. The timed “Up & Go”: A test of basic functional mobility for frail elderly persons. J Am GeriatrSoc 1991;39:142-8. 23. Ng SS, Hui-Chan CW. The timed up & go test: Its reliability and association with lower-limb impairments and locomotor capacities in people with chronic stroke. Arch Phys Med Rehab 2005;86:1641-7.
422 423 424
24. Portney LG, Watkins MP. Foundations of clinical research: applications to practice. 3rd ed. Upper Saddle River, NJ: Prentice Hall; 2007.
425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441
25. Zweig MH, Campbell G. Receiver-operating characteristic (ROC) plots: A fundamental evaluation tool in clinical medicine. ClinChem 1993;39:561-77.
442
30. Dettmann MA, Linder MT, Sepic SB. Relationships among walking performance,
SC
M AN U
26. Wing K, Lynskey JV, Bosch PR. Walking speed in stroke survivors: considerations for clinical practice. Topics Geriatric Rehab 2012;28:113-21.
TE D
27. Carvalho C, Sunnerhagen KS, Willén C. Walking performance and muscle strength in the later stage poststroke: a nonlinear relationship. Arch Phys Med Rehab 2013;94:845-50. 28. Harris J, Eng J, Marigold D, Tokuno CD, Louis CL. Relationship of balance and mobility to fall incidence in people with chronic stroke. PhysTher 2005;85:150-8.
EP
29. de Oliveira CB, de Medeiros ÍRT, Frota NAF, Greters ME, Conforto AB. Balance control in hemiparetic stroke patients: main tools for evaluation. J Rehab Res Dev 2008;45:1215-26.
AC C
443 444 445 446 447 448 449 450 451
RI PT
419 420 421
postural stability, and functional assessments of the hemiplegic patient. Am J Phys Med 1987;66:77-90.
31. Nakamura R, Watanabe S, Handa T, Morohashi I. The relationship between walking speed and muscle strength for knee extension in hemiparetic stroke patients: a follow-up study. Tohoku J Exp Med 1988;154:111-3. 32. Nadeau S, Gravel D, Arsenault AB, Bourbonnais D. Plantarflexor weakness as a limiting factor of gait speed in stroke subjects and the compensating role of hip 18
ACCEPTED MANUSCRIPT
452 453
33. Blum L, Korner-Bitensky N. Usefulness of the Berg Balance Scale in stroke rehabilitation: a systematic review. Phys Ther 2008;88:559-66.
454 455 456
34. Kobayashi T, Leung AK, Akazawa Y, Hutchins SW. Correlations between Berg balance scale and gait speed in individuals with stroke wearing ankle-foot
480 481 482 483 484 485 486 487 488 489
RI PT
SC
strength and muscle fiber characteristics. Eur J Appl Physiol Occup Physiol 1993;66:254–62
M AN U
36. Masui T, Hasegawa Y, Matsuyama Y, Sakano S, Kawasaki M, Suzuki S. Gender differences in platform measures of balance in rural community-dwelling elders. Arch Gerontol Geriatr 2005;41:201-9. 37. Butler AA, Menant JC, Tiedemann AC, Lord SR. Age and gender differences in seven tests of functional mobility. J Neuroeng Rehabil 2009;6:31-9
TE D
463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479
35. Miller AE, MacDougall JD, Tarnopolsky MA, Sale DG. Gender differences in
EP
460 461 462
orthoses - a pilot study. Disabil Rehabil Assist Technol 2014;23:1-4.
AC C
457 458 459
19
ACCEPTED MANUSCRIPT
490 491
Figure Legend
492 Fig 1. Receiver operating characteristic curves. A. ROC curve for PWT Time (Path
494
width = 20cm) between healthy individuals and individuals with stroke (AUC=.885;
495
sensitivity=84%; specificity=80%). B. ROC curve for PWT Time (Path width =
496
30.5cm) between healthy individuals and individuals with stroke (AUC=.891;
497
sensitivity=89%; specificity=71%). C. ROC curves for PWT Time (Path width =
498
38cm) between healthy individuals and individuals with stroke (AUC=.894;
499
sensitivity=87%; specificity=74%)
M AN U
SC
RI PT
493
AC C
EP
TE D
500
20
ACCEPTED MANUSCRIPT
Table 1 Demographics of the 2 Subject Groups Stroke (n=37)
Healthy (n=35)
p
Age (y)
62.0 ± 6.2
64.3 ± 7.8
.172
Sex (M/F)
26/11
11/24
.001*
Height (cm)
164.1 ± 7.7
160.6 ± 9.2
.086
67.5 ± 9.0
58.5 ± 10.9
Body mass index (kg/m )
25.1 ± 2.7
22.6 ± 3.7
Years since stroke
7.8 ± 3.0
NA
Weight (kg) 2
RI PT
Descriptor
SC M AN U TE D EP AC C
