Abstracts

Sporadic [ldquo]benign[rdquo] mesial temporal lobe epilepsy (BMTLE) is a rather common epileptic syndrome with typical onset in adulthood, in which genetic factors seem to play a major etiopathogenetic role. Its relationship with severe mesial TLE is far more complex, but evidence has emerged that BMTLE and severe pharmacoresistant TLE might lie on a biological continuum. In this study, we wished to determine the occurrence of magnetic resonance imaging-detected mesial temporal sclerosis (MTS) in patients with sporadic BMTLE. The study group consisted of consecutive 98 unrelated patients (50 female, mean age 49.7 years, SD [plusmn] 18.1; range 5 to 81) with BMTLE, who rarely or never had seizures at long-term ([lt] 2years) follow-up. The diagnosis of TLE was mainly based on typical temporal auras and/or interictal EEG discharges with a maximum over the temporal lobes. A familiar history of febrile convulsions or epilepsy was observed in 37% of the patients. Twenty-two% of the patients had a personal history of febrile convulsion, which were simple in almost all of them. The mean age at seizure onset was 28.7 years (SD [plusmn] 24.7), the mean duration of epilepsy was 17.1 years (SD [plusmn] 15.7). In all patients, brain MR images were obtained using sequences and slices to optimize visual detection of mesial temporal structures. Thirty-six percent (35/98) of the patients had MRI evidence of MTS. In detail, 18 had left MTS, 16 had right MTS, while in the remaining patient there was evidence of bilateral MTS. Hyperintense FLAIR and T2 signal with or without mesial temporal atrophy was observed in 22 of these 35 individuals. MRI abnormalities correlated with the epileptogenic focus defined by lateralized EEG discharges, with or without lateralized seizure features. These results indicate that MRI evidence of MTS is often encountered in BMTLE. In this way, our findings reinforce the belief that MTS is not necessarily related to seizure severity, and that other factors, both genetic and environmental, play an important role in determining seizure severity in patients with TLE.