Abstracts

Rationale: Recent studies using fMRI and connectivity analyses show a link in normal populations between left dominant frontal language networks and the contralateral cerebellum. Neuropsychological data suggest that disruption of the right cerebellum is associated with impairments in verbal fluency and verbal working memory. In epilepsy populations, there is a higher likelihood of atypical language representation. We aimed to characterize lateralization of the cerebellum in children with pediatric epilepsy and explore the relationship to lateralization of IFG and language skills as compared to controls. Methods: 35 epilepsy patients with left hemisphere focal epilepsy [21 M; mean age 8.8 years, range 4-12; WASI FSIQ 100±16] were compared to a normative group of typically developing children [n=64; 33 M; mean age 8.6 years, range 4-12; WASI FSIQ 115±14]. Patients had normal MRI; mean age of onset 5.35 years; seizure frequency ranging from daily to once a year; and most were on one drug (range 0-3). Patients and controls were divided into three age groups: 4-6yr, 7-9yr, and 10-12yr. Subjects underwent neuropsychological testing and EPI BOLD fMRI (3T) while performing an age-adjusted word definition task (reverse speech control). Data were analyzed using SPM2 [FWE<0.05 corrected group map]. ROI laterality indices [LI=(∑Lvox -∑Rvox)/(∑Lvox+∑Rvox)] for inferior frontal gyrus (IFG) and cerebellum (CBM) were computed using LI Toolbox bootstrap method; LI<0.20 defined atypical language dominance. Partial correlations, regression analyses, and multivariate analyses of variance were conducted.