The Impact of Cognitive Fatigue on Ongoing Processing Speed Task Performance in People with Multiple Sclerosis

Poster Session B - Sunday, April 14, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Marissa Tripoli¹ (mptripol@buffalo.edu), David W. Shucard¹, Hope Nyarady¹, Ryan O'Donnell¹, Mckenzie Haller¹, Bianca Weinstock-Guttman¹, Ralph HB Benedict¹, Thomas J. Covey¹; ¹University at Buffalo

Multiple Sclerosis (MS) is a neurodegenerative, demyelinating disorder. People with MS (PwMS) often report experiencing mental or cognitive fatigue, which can significantly disrupt their performance in tasks of daily living. Cognitive fatigue can be thought of as the exacerbation of fatigue over time while engaging in cognitively demanding activities. In the present study, we identified novel indices of cognitive fatigue during ongoing performance of a processing speed task in PwMS. We hypothesized that PwMS would demonstrate a steeper decline in cognitive performance as a function of time-on-task in comparison to healthy control participants. Study participants completed a computerized Symbol Digit Modalities Test (SDMT), which is a well-validated, sensitive measure of processing speed in MS. Response speed was recorded for each trial, and event-related brain potentials (ERPs) were derived from ongoing electroencephalographic (EEG) data recorded during task performance. Analyses indicated a gradual slowing of response speed over the course of task performance in PwMS, whereas response speed became faster and stabilized with increased time-on-task in healthy controls. These findings suggest a task-learning effect for control participants that was counteracted by the influence of cognitive fatigue with increased time-on-task in the MS group. ERP analyses also indicated that individual differences in neural activity in PwMS were associated with behavioral indices of cognitive fatigue. The findings provide preliminary evidence that cognitive fatigue diminishes the benefits of task learning in PwMS. The results have implications for the interpretation of neuropsychological test performance and development of strategies for improving aspects of daily living in PwMS.

Topic Area: EXECUTIVE PROCESSES: Other