Introduction: Walking is perceived as the most important bodily function for persons with multiple sclerosis (pwMS) and is impaired in more than 70% of pwMS. In addition, the effect of multiple sclerosis (MS) on gait pattern increases in fast walking and during fatiguing exercises, altering the spatiotemporal gait parameters and walking reserve.
Objectives: The objective of this study is to investigate the impact of a 12 min intermittent-walking protocol on spatiotemporal gait parameters and on the fatigability of pwMS, as well as the association with perceived exertion and reported symptoms of fatigue.
Methods: Twenty-six persons with relapse-remitting MS and twenty-eight healthy controls (HCs) were included in this cross-sectional study. The Modified Fatigue Impact Scale and the Symbol Digit Modality Test were used to evaluate fatigue symptoms and cognitive function, respectively. Participants walked six times during an uninterrupted 2-min period. Before, during the rest periods and after the last 2 min walk, the rate of perceived exertion (RPE) was measured using the Borg Scale, and the spatiotemporal gait parameters were assessed with GaitRite. The cut-off value of 10% deceleration of the distance walked index classified pwMS into two groups: MS Fatigable (MS-F) and MS Non-Fatigable (MS-NF). One-way and two-way Analyses of variance (ANOVAs) were used to verify the effect of time and groups, respectively.
Results: PwMS walked slower, travelled shorter distances, and presented shorter step lengths compared to HCs. No effects of the intermittent-walking protocol were found for all pwMS, but the MS-F group had deteriorated walking speed, step length, and cadence. Walking dysfunction was associated with perceived fatigability, reported symptoms of fatigue, cognitive function, and disability. Reported symptoms of fatigue was associated with perceived exertion but not with performance fatigability.
Conclusions: Changes in gait parameters were weak to moderately associated with performance fatigability and the perception of effort and disability but not with reported fatigue symptoms, highlighting distinct constructs. The walking speed reserve and step length reserve also emerged as potential early markers of performance decline.
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