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 MEASURES

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.