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.
To determine the reliability, precision and clinically important change of the Timed25-Foot Walk (T25FW), Six-Minute Walk (6MW), Multiple Sclerosis Walking Scale-12 (MSWS-12) and accelerometry.
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.
All outcome measures were reliable with precision and MDC varying between measures in the whole sample: T25FW ICC=0.991, SEM=1s, CV=6.2%, MDC=2.7 s (36%); 6MW ICC=0.959, SEM=32m, CV=6.2%, MDC=88m (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, (42%). Variation in these estimates was seen based on disability level and walking aid.
Reliability of these outcomes is good; falling within acceptable ranges. Precision and clinically important change estimates provide guidelines for interpreting these outcomesin clinical and research settings.