Cerebellar language mapping and cerebral language dominance in pediatric epilepsy surgery patients

OBJECTIVE Children with epilepsy often have reorganization of language networks and abnormal brain anatomy, making determination of language lateralization difficult. We characterized the proportion and distribution of language task activation in the cerebellum to determine the relationship to cerebral language lateralization. METHODS Forty-six pediatric epilepsy surgery candidates (aged 7-19 years) completed an fMRI auditory semantic decision language task. Distribution of activated voxels and language laterality indices were computed using: (a) Broca's and Wernicke's areas and their right cerebral homologues; and (b) left and right cerebellar hemispheres. Language task activation was anatomically localized in the cerebellum. RESULTS Lateralized language task activation in either cerebral hemisphere was highly correlated with lateralized language task activation in the contralateral cerebellar hemisphere (Broca vs. cerebellar: ρ = -0.54, p < 0.01). Cerebellar language activation was located within Crus I/II, areas previously implicated in non-motor functional networks. CONCLUSIONS Cerebellar language activation occurs in homologous regions of Crus I/II contralateral to cerebral language activation in patients with both right and left cerebral language dominance. Cerebellar language laterality could contribute to comprehensive pre-operative evaluation of language lateralization in pediatric epilepsy surgery patients. Our data suggest that patients with atypical cerebellar language activation are at risk for having atypical cerebral language organization.