Contribution of the cerebellum to cognitive performance in children and adolescents with multiple sclerosis.

BACKGROUND

Posterior fossa lesions are common in pediatric-onset multiple sclerosis (MS), which is of concern, given the known role of the cerebellum in cognition.

OBJECTIVES

To investigate the relationship between cerebellar pathology and cognitive function in youth with pediatric-onset MS.

METHODS

Twenty-eight pediatric-onset relapsing-remitting MS patients (21 girls; mean age 16.2 years; mean disease duration 4.3 years, median Expanded Disability Status Scale 1.25) were compared to 33 age- and sex-matched healthy controls. Participants underwent structural magnetic resonance imaging (MRI) and neuropsychological evaluation to assess intelligence, attention, processing speed, language, visuo-motor integration, and fine-motor dexterity. Associations between cognitive outcomes and cerebellar volume independent of cerebral volume were examined.

RESULTS

Cognitive and motor performance of the MS group was reduced relative to controls (all p<0.003). While cerebellar volumes did not differ between groups, cerebellar posterior lobe volume and infratentorial lesion volume accounted for extra variance on measures of information processing (R(2)=0.43; p=0.02) and vocabulary (R(2)=0.56; p=0.04) in patients (controlling for cerebral volume and sex), but not in controls.

CONCLUSION

Smaller cerebellar posterior lobe volume, a known region for cognitive processing, and increased lesion burden in the posterior fossa adversely impact cognitive function, an important functional consequence of MS onset during childhood.