TY - JOUR
T1 - The reliability, precision and clinically meaningful change of walking assessments in multiple sclerosis
AU - Learmonth, Yvonne C.
AU - Dlugonski, Deirdre D.
AU - Pilutti, Lara A.
AU - Sandroff, Brian M.
AU - Motl, Robert W.
PY - 2013/11
Y1 - 2013/11
N2 - Background: Assessing walking impairment in those with multiple sclerosis (MS) is common, however little is known about the reliability, precision and clinically important change of walking outcomes. Objective: The purpose of this study was to determine the reliability, precision and clinically important change of the Timed 25-Foot Walk (T25FW), Six-Minute Walk (6MW), Multiple Sclerosis Walking Scale-12 (MSWS-12) and accelerometry. Methods: Data were collected from 82 persons with MS at two time points, six months apart. Analyses were undertaken for the whole sample and stratified based on disability level and usage of walking aids. Intraclass correlation coefficient (ICC) analyses established reliability: standard error of measurement (SEM) and coefficient of variation (CV) determined precision; and minimal detectable change (MDC) defined clinically important change. Results: All outcome measures were reliable with precision and MDC varying between measures in the whole sample: T25FW: ICC=0.991; SEM=1 s; CV=6.2%; MDC=2.7 s (36%), 6MW: ICC=0.959; SEM=32 m; CV=6.2%; MDC=88 m (20%), MSWS-12: ICC=0.927; SEM=8; CV=27%; MDC=22 (53%), accelerometry counts/day: ICC=0.883; SEM=28450; CV=17%; MDC=78860 (52%), accelerometry steps/day: ICC=0.907; SEM=726; CV=16%; MDC=2011 (45%). Variation in these estimates was seen based on disability level and walking aid. Conclusion: The reliability of these outcomes is good and falls within acceptable ranges. Precision and clinically important change estimates provide guidelines for interpreting these outcomes in clinical and research settings.
AB - Background: Assessing walking impairment in those with multiple sclerosis (MS) is common, however little is known about the reliability, precision and clinically important change of walking outcomes. Objective: The purpose of this study was to determine the reliability, precision and clinically important change of the Timed 25-Foot Walk (T25FW), Six-Minute Walk (6MW), Multiple Sclerosis Walking Scale-12 (MSWS-12) and accelerometry. Methods: Data were collected from 82 persons with MS at two time points, six months apart. Analyses were undertaken for the whole sample and stratified based on disability level and usage of walking aids. Intraclass correlation coefficient (ICC) analyses established reliability: standard error of measurement (SEM) and coefficient of variation (CV) determined precision; and minimal detectable change (MDC) defined clinically important change. Results: All outcome measures were reliable with precision and MDC varying between measures in the whole sample: T25FW: ICC=0.991; SEM=1 s; CV=6.2%; MDC=2.7 s (36%), 6MW: ICC=0.959; SEM=32 m; CV=6.2%; MDC=88 m (20%), MSWS-12: ICC=0.927; SEM=8; CV=27%; MDC=22 (53%), accelerometry counts/day: ICC=0.883; SEM=28450; CV=17%; MDC=78860 (52%), accelerometry steps/day: ICC=0.907; SEM=726; CV=16%; MDC=2011 (45%). Variation in these estimates was seen based on disability level and walking aid. Conclusion: The reliability of these outcomes is good and falls within acceptable ranges. Precision and clinically important change estimates provide guidelines for interpreting these outcomes in clinical and research settings.
KW - EDSS
KW - Multiple sclerosis
KW - clinical change
KW - mobility
KW - outcome measures
KW - precision
KW - reliability
KW - walking
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U2 - 10.1177/1352458513483890
DO - 10.1177/1352458513483890
M3 - Article
C2 - 23587605
AN - SCOPUS:84887563800
SN - 1352-4585
VL - 19
SP - 1784
EP - 1791
JO - Multiple Sclerosis Journal
JF - Multiple Sclerosis Journal
IS - 13
ER -