Abstracts

To study patterns of language representation in right handed (RH) children with refractory epilepsy using functional MRI (fMRI), 20 children with refractory epilepsy referred for language lateralization by fMRI completed 2 of 3 standardized block design language tasks (verb generation, fluency, object naming).Rregion of interest (ROI) analysis was applied to the task which produced activation of both anterior (frontal) and posterior (temporal) language areas using AFNI. An Asymmetry Index (AI) for anterior and posterior language areas was calculated (AI = -0.1 - +0.1; mixed dominance)., 9/13 children with left hemisphere (LH) seizure focus (SF) (Group A) and 4/7 with R-hemisphere (RH) focus (Group B) had bilateral language activation. 6 children (46%) in group A had RH dominance; mean anterior AI +0.67, mean posterior AI +0.34 (p=0.25). No children in group B had RH dominance. Mean posterior AI in group A did not statistically differ from the mean posterior AI in group B (p=0.26). Neither age of epilepsy onset or pathology affected AI., Bilateral language activation was seen irrespective of the side of SF; however, only children with L-SF had RH dominance. Posterior language area shifted more frequently than anterior area. Thus, while atypical patterns of language activity are common in this group of RH children with refractory epilepsy, true RH dominance was only seen in the presence of a left SF.[table1],