Abstracts

Rationale: To evaluate evolution and elucidate clinical phenotypes related to prognosis of patients with non-lesional temporal lobe epilepsy (TLE-NL) treated exclusively with antiepileptic drugs (AED). Methods: We reviewed clinical, radiological, and EEG findings in eighty-four patients with TLE-NL who were treated at our institute between 2006 and 2011. The population was classified into the good response group (GRG) and the poor one (PRG), according to the duration of the seizure-free period along their evolution; longer than at least one year or not (shorter than 1 year). Dependent variables on demographic and clinical features were compared between two groups on the basis of a cross-sectional study design. Results: There were 46 (54.8%) patients belonging to GRG and the other 38 (45.2%) patients with PRG. Patients of GRG had seizure-free periods with a mean duration of 52 months (4.3 years). The average number of AED was significantly smaller in GRG (1.3±0.8) than that of PRG (2.8±1.0, p < 0.05). GRG showed the pattern of significantly older age at onset of epilepsy (28.6±18.6 vs 20.8±12.7 years, p < 0.05), and fewer incidence of the initial precipitating events like febrile seizures, CNS infection and head trauma (1.1% vs 8.3%, p < 0.05). In addition, not only interictal EEG abnormalities but aura, generalized convulsion, and ictal automatism during the habitual seizures was more frequently found in PRG (15.5% vs 4.8%, p < 0.01). Multivariate analysis showed that a presence of automatism and initial precipitating events are associated with poor prognosis (p < 0.05). However, there was no statistically significant difference in the other variables between two groups. Conclusions: Contrary to common sense of the intractability of TLE, we could find that more than 54% patients with TLE-NL can achieve a seizure free with the optimal AED therapy. Older age at onset predicts better response to AEDs in TLE-NL. On the other hand, the presence of automatism and initial precipitating events is implicated in a poor response to AED. Future prospective, well controlled studies with much larger population should be warranted.