Better Cognitive Function Predicts Maintenance of Dual-Task Walking Ability Over Time Among People With Relapsing-Remitting MS

Objective: Physical fitness and preserved cognitive function may provide neuroprotection in multiple sclerosis (MS), but few studies have examined their role in symptom progression over time. Dual-task paradigms can be useful to detect subtle impairment among people with MS in early stages of the disease. The present study investigated whether higher aerobic fitness or greater cognitive function could predict performance in dual-task walking 1-2 years later among people with mild or no MS-related walking impairment. Method: Participants (n = 50) performed dual-task walking (walking while serially subtracting 7's from 100), completed the Montreal Cognitive Assessment (MoCA), the Symbol Digit Modalities Test (SDMT), and a fitness test (VO2max). They were tested at two time points (T1 and T2), approximately 1 year apart. Walking speed, MoCA, SDMT, and VO2max at baseline (T1) were examined as predictors of dual-task walking speed at T2. Results: MoCA (higher score), but not SDMT or fitness, was significantly correlated with percentage decrease in dual-task walking and was a significant predictor of dual-task-walking speed at T2, accounting for additional 6.1% of its variance. Cognitive impairment (MoCA < 26) at baseline corresponded to a 12 cm/s unit decrease in dual-task-walking speed at T2. Conclusions: Our results provide longitudinal evidence that better cognitive function, specifically global MoCA score, may protect against decline in dual-task walking ability over the years.