Differential cerebellar activation on functional magnetic resonance Imaging during working memory performance in persons with multiple sclerosis

Objective: To explore the potential role of the cerebellum in working memory dysfunction in multiple sclerosis (MS). Design: Blood oxygen level dependent functional magnetic resonance imaging (fMRI) was used to examine cerebellar activation during a working memory task. Setting: University-affiliated medical rehabilitation facility. Participants: Eight persons with MS and 5 healthy controls. Interventions: Not applicable Main Outcome Measure: Change in hemodynamic response. fMRI data were acquired and subsequently analyzed by using Statistical Parametric Mapping. Results: Both the control and MS groups showed significantly greater activations in the right cerebellar hemisphere as compared With the left side. Persons with MS, however, showed no detectable activations in 4 cerebellar substructures that were significantly active in controls (ie, right vermis, right dentate nucleus, right tonsil, cerebellar peduncle). Conclusions: The significantly decreased cerebellar activation in the MS group suggests that the cerebellum may play a role in the working memory impairment observed in MS.