Article

The six-minute walk (6MW) is a common walking outcome in multiple
sclerosis (MS) thought to measure fatigability in addition to overall walking
disability. However, direct evidence of 6MW induced gait deterioration is limited
by the difficulty of measuring qualitative changes in walking. OBJECTIVES: This
study aims to (1) define and validate a measure of fatigue-related gait
deterioration based on data from body-worn sensors; and (2)
use this measure to
detect gait deterioration induced by the 6MW. METHODS:
Gait deterioration was
assessed using the Warp Score, a measure of similarity between gait cycles based
on dynamic time warping (DTW). Cycles from later minutes were compared to
baseline cycles in 89 subjects with MS and 29 controls. Correlation, corrected
(partial) correlation, and linear regression were used to quantify relationships
to walking and fatigue outcomes. RESULTS: Warp Scores rose between minute 3 and
minute 6 in subjects with mild and moderate disability (p<0.001). Statistically
significant correlations (p<0.001) to the MS walking scale (MSWS-12), modified
fatigue impact scale (MFIS) physical subscale, and cerebellar and pyramidal
functional system scores (FSS) were observed even after controlling for walking
speed. Regression of MSWS-12 scores on Warp Scores and walking speed explained
73.9% of response variance. Correlations to individual MSWS-12 and MFIS items
strongly suggest a relationship to fatigability. CONCLUSION:
The Warp Score has
been validated in MS subjects as an objective measure of fatigue-related gait
deterioration. Progressive changes to gait cycles induced by the 6MW often
appeared in later minutes, supporting the importance of sustained walking in
clinical assessment.
CI - Copyright (c) 2016 Elsevier B.V. All rights reserved.

Langue : ANGLAIS