Exploring Differences in the Lateralized Readiness Potential in Persons With Multiple Sclerosis Compared to Healthy Controls.

Multiple sclerosis (MS) is a neurodegenerative disease often leading to cognitive and motor impairment. Little research has examined motor preparation and initiation outcomes in the brain among persons with MS. The lateralized readiness potential is an ERP component that indexes pre-motor activity evaluating the stimulus (LRP-S) and motor activation for the response (LRP-R). We examined the LRP-S and LRP-R in MS and healthy controls (HC) to understand impairments in neural activity associated with response activation and selection. Persons with MS (n = 53) and HC (n = 53) completed a flanker task with concurrent EEG for LRP extraction. Paired t-tests were conducted to determine differences for accuracy, reaction time (RT), LRP-S, and LRP-R. Within-group Pearson correlations were conducted to investigate the relationship between LRP indices and behavioral performance. Participants with MS had delayed LRP-S latency and reduced LRP-R amplitudes compared to HC for both trial types. In the HC group, LRP-S amplitude and latency were positively related to RT. In the MS group, LRP-S latency was positively related to RT. In both MS and HC, incongruent LRP-R latency was negatively related to RT, suggesting that individuals with a shorter time interval between activation and response had faster reaction times. Persons with MS had delayed response selection, and less neural response activation compared to HC. Impairment in MS is evident for both pre-motor and motor response initiation during a selective attention task. Our study also provided evidence the relationship between action-based components and task performance differ in persons with MS and HC.