Abstracts

fMRI provides a non-invasive way to assess the re-organization of language networks in patients with localization related epilepsy. We sought to identify the patterns and location of language activation in atypical language dominant epilepsy patients. We studied 24 atypical language dominant patients (14 right handed, 7 left handed, 3 ambidextrous; 13 M, 11 F; aged 8.5-45 years), mean age of seizure onset, 8.3 years (range 0.5-29), with vEEG, MRI, and fMRI. 5 patients had mesial temporal sclerosis, 4 had stroke, 5 had tumor/dysplasia, and 10 had normal MRI. Twenty patients had a temporal lobe focus (11 left, 4 right, 1 bitemporal), 4 had an extratemporal focus (2 left, 2 right). Whole brain EPI BOLD fMRI at 1.5T, employed a box car design; the task panel included verbal fluency, category description, reading comprehension, and auditory comprehension. Data were analyzed using semi-automated methods and displayed as t-maps. Data were visually inspected and coded to determine activation in brain regions (left, right, or bilateral for frontal lobe (inferior frontal gyrus, midfrontal gyrus, or temporal lobe (Wernicke[apos]s area) regions). Seven of 24 patients (29.2%) had consistently right hemisphere lateralized language representation across brain regions; 11 of 24 (45.8%) had bifrontal, but uniformly lateralized temporal activation (5 right temporal, 6 left temporal); 3 of 24 (12.5 %) had bifrontal and bitemporal activation; and, 3 of 24 (12.5) had a diaschisis where frontal and temporal language areas were represented in opposite hemispheres. Only two patients had activation outside of typical or homologous brain regions. Atypical language representation is expressed within homologous language areas in the typically non-dominant hemisphere, and rarely in areas outside classic language areas. Four distinct language patterns were identified. Larger series are necessary to draw firm conclusions regarding the influence seizure focus and remote symptomatic etiology on atypical language patterns. (Supported by Clinical Epielpsy Section, NINDS, NIH and NINDS, NIH R01NS44280)