Mobile Brain/Body Imaging of cognitive-motor impairment in multiple sclerosis: Deriving EEG-based neuro-markers during a dual-task walking study

Objective: Individuals with a diagnosis of multiple sclerosis (MS) often present with cognitive and motor deficits, and thus the ability to perform tasks that rely on both domains may be particularly impaired. Yet, dual-task walking studies yield mixed results. Individual variance in the ability to cope with brain insult and mobilize additional brain resources may contribute to mixed findings. Methods: To test this hypothesis, we acquired event-related potentials (ERP) in individuals with MS and healthy controls (HCs) performing a Go/NoGo task while sitting (i.e., single task) or walking (i.e., dual-task) and looked at the relationship between task related modulation of the brain response and performance. Results: On the Go/NoGo task the MS group showed dual-task costs when walking, whereas HCs showed a dual-task benefit. Further, whereas the HC group showed modulation of the brain response as a function of task load, this was not the case in the MS group. Analysis for the pooled sample revealed a positive correlation between load-related ERP effects and dual-task performance. Conclusions: These data suggest a neurophysiological marker of cognitive-motor dysfunction in MS. Significance: Understanding neural processes underlying dual-task walking will help identify objective brain measurements of real-world issues and may improve assessment of MS.