Walking and thinking in persons with multiple sclerosis who vary in disability.

OBJECTIVE: To examine the effect of a cognitive task on spatiotemporal parameters of gait in persons with multiple sclerosis (MS) with varying disability. DESIGN: Cohort. SETTING: Testing occurred at a local hospital. PARTICIPANTS: Community-living persons (N=78) with MS participated in this investigation. They were divided into 3 groups based on Expanded Disability Status Scale (EDSS) scores: mild (2.0-3.5 EDSS; n=21); moderate (4.0-5.5 EDSS; n=25); and severe (6.0-6.5 EDSS; n=32). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Participants walked at a self-selected pace on an electronic pathway, which recorded spatiotemporal parameters of gait, in 4 separate trials and completed a cognitive task in the last 2 trials. The effect of the cognitive task was quantified as the change in spatiotemporal parameters of gait. RESULTS: There was an overall decline in gait with the additive cognitive task. The magnitude of the adverse changes ranged from 1.8% for step length (P=.02) to 12% for gait velocity (P<.001). Moreover, adverse changes in gait function were greatest in the severe and moderate disability group (P<.05). CONCLUSIONS: Persons with MS have impaired walking while doing a cognitive task, and the adverse effect of a cognitive task on walking function is greatest in persons with severe and moderate disability. Difficulty walking while thinking has implications for everyday life and may be related to the risk of falls. Further work is needed to determine whether the adverse effect of an additive cognitive task can be minimized with rehabilitative interventions.