Nonlesional mild temporal lobe epilepsy. A common, unrecognized disorder with onset in adulthood

Background: We delineate the electroclinical picture of nonlesional mild temporal lobe epilepsy (TLE), a still undefmite disorder. Methods: we reviewed clinical and MRI data of 104 consecutive patients with nonlesional TLE. Seventhythree/104 fulfilled inclusion criteria of both epilepsy history and follow-up longer than 3 years at our Institute. Results: Fourthy-three/73 (59%) patients had mild TLE. When compared with 30/73 (41%) patients with severe TLE, age at onset was significanüy higher (mean 34.3yrvs 7.8yr). There was also a significantly higher prevalence of: positive family history of epilepsy (37.2%ra 10%), normal interjetai EEG (23.3% v s 0%), and delayed diagnosis (39.0% v s 0%), and a significantly inferior occurrence of: febrile convulsions (4.7%vs 33.3%), mesial temporal sclerosis (6.9%vs 36.7%), and intelligence deficiency (0%vs 20%). Conclusions: mild non-lesional TLE is a common, unrecognized disorder which starts in adulthood. In contrast to severe TLE, genetic predisposition rather than prolonged febrile convulsions appears to be an important causal factor.