Functional Activation Patterns in Pediatric-Onset Multiple Selerosis: Does Physical Activity Play a Role in the Maintenance of Working Memory

Cognitive impairment occurs in only 30% of patients with pediatric-onset multiple sclerosis (POMS), despite significant brain pathology, suggesting that mechanisms facilitating adaptation to pathology may be occurring. We examined executive control processing in 20 cognitively-preserved POMS patients and 20 age and sex-matched healthy controls, using a working memory task, while participants underwent functional neuroimaging. Participants also completed a neuropsychological battery and structural imaging in a 3T scanner. Findings suggest that inefficient processing and/or compensatory recruitment occurs in cognitively-preserved POMS patients for working memory tasks, at both low and high levels of executive demand. Strenuous physical activity had limited correlations with recruitment in POMS patients, but was predictive of whole-brain grey and white matter volume, as well as relapse rate, suggesting that engagement in aerobic activity may have a protective rather than enhancing role.