Possible remote functional reorganization in left temporal lobe epilepsy.

OBJECTIVE: To provide functional magnetic resonance imaging-based insight into the impact of left temporal lobe epilepsy (TLE) on language-related functional re-organization. MATERIALS AND METHODS: Ten right-handed patients with left TLE were compared with 10 matched healthy controls. Regional brain activation during the language task was measured in the inferior frontal gyrus (IFG) and in the superior temporal gyrus (STG), and the regional inter-hemispheric lateralization index (LI) was calculated. RESULTS: Left language lateralization was documented in all the patients and controls. Reduced lateralization in the IFG was due to decreased activity in the left frontal region rather than to increased activity in the right frontal region. The LI values in the STG correlated with the LI values in the IFG in the controls but not in the patients. CONCLUSIONS: The left IFG was most probably involved in the epileptogenesis and concomitant language-related cortical plasticity in patients with left TLE.