Abstracts

RATIONALE: Recent neuroimaging studies demonstrated a greater variability of language dominance in right-handed epilepsy patients as compared to neurologically normal subjects. The aim of this study was to describe the cortical areas involved in language tasks in patients with TLE. Our second goal was to compare the activation pattern between left TLE patients, right TLE patients and control subjects. METHODS: Nine patients with left TLE, nine with right TLE and eight neurologically normal subjects were studied using BOLD fMRI and EPI (1,5 T). All subjects were right-handed. Tasks used were semantic verbal fluency and covert sentence repetition. Data were analyzed using SPM96 software and a group analysis. RESULTS: In the neurologically normal subjects, activation was observed predominantly in the left frontal lobe for the fluency task. The repetition task activate the superior temporal gyri symetrically and the frontal lobes (Left predominant). Right TLE patients showed a roughly similar pattern of activation, but without right frontal lobe activation in any task. Left TLE patients showed a clearly different pattern consisting in right predominant frontal activation in the fluency task. In the repetition task, activation was observed in the superior temporal gyri asymetrically, restricted to the posterior part of the left temporal lobe. CONCLUSIONS: This study is in favour of a functional reorganization of language areas in left TLE patients as compared to right TLE patients and neurologically normal subjects. The right predominant frontal activation in the left TLE patients suggests that functional reorganization extend beyond the pathologic temporal lobe.