Abstracts

Rationale: Frontal lobe epilepsy (FLE) is the most common type of neocortical focal epilepsy. It frequently evolves with pharmacoresistant seizures, thus impacting quality of life of affected patients. FLE has variable clinical and etiological profiles that challenge diagnosis and treatment planning. Objectives: 1. to characterize the clinical profile of a series of pharmacoresistant and surgically treated FLE patients; 2. to analyze the results of presurgical evaluation, and 3. to assess prognostic factors influencing post-surgical outcome . Methods: 66 patients evaluated at the Ribeirão Preto Epilepsy Surgery Program (São Paulo, Brazil) between July 1994 and December 2006 were included. All patients fulfilled at least one of the following inclusion criteria: (I) patients with frontal lobe seizures according to ILAE criteria; (II) frontal lobe MRI lesion; (III) seizure semiology and/or ictal EEG consistent with FLE. There were 41 males and 25 females, whose mean age at seizure onset was 6.82 +/-7.92 years, mean age at surgery was 21.3 +/- 13.36 years. We collected demographic data, date of surgery, side of surgery, history of status epilepticus, presence of generalized tonic-clonic seizures, family history of epilepsy, seizure semiology and frequency, results of pre-operative and post-operative MRI, psychiatric evaluation and video EEG monitoring analysis. Mean follow-up was 5.36± 2.63 yrs (2-12 years), and postsurgical seizure outcome followed Engel Classification. For statistical analysis we performed Mann-Whitney, Qui-Square. Fisher Exact Test, binary logistic regression and Kaplan-Meir survival analysis. Results: 64% of patients had favorable post-surgical outcome (Engel Classes I and II). Variables predicting favorable outcome were surgery performed up to 29 years old (p=0.02), normal neurological status (p=0.02), absence of psychiatric comorbidity (p=0.001), and presence of MRI lesion (p=0.05). Diffuse ictal EEG pattern was correlated with unfavorable outcome (p=0.01). Conclusions: Surgery is an efficient therapeutic alternative for treating pharmacoresistant frontal lobe epilepsy, being efficient in two thirds of the patients. Younger patients with normal neurological and psychiatric status, and with focal MRI lesion had better outcome.