Abstracts

Rationale: Nearly 80% of patients with mesial temporal lobe epilepsy (MTE) associated with hippocampal sclerosis (HS) are medically resistant and need presurgical evaluation and if possible surgical treatment. Objective: To identify electroclinical and neuroimaging features related to seizure control after medical o surgical treatment in patients with MTE associated with HS. Methods: Patients with clinical, MRI and EEG features of mesial temporal lobe epilepsy associated with HS who were referred for presurgical evaluation at the Hospital Clínic or were followed up in the outpatient clinic of 3 other tertiary centers without surgical programme were included in the study. Patients with clinical and laboratory features that place the diagnosis of MTLE in doubt were excluded. Parametric and non parametric test for univariate analysis were used and regression analysis when correlating continuous variables. Results: Two hundred and two patients( 84 men/ 118 women) were included, mean age 44 (16-80), mean age at epilepsy onset 16 (0-77). Referred initial precipitating injury (IPI) 119 (67%) being the most frequent a febrile seizure 56 (32%), mean age at IPI 5.19 (0-65). Aura was referred by 130 (67%) but aura persisted upon the time just in 98 (79%) of these patients. Seizure freedom (no complex partial seizures in a year) was reported by 39 (19.3%). From the medically resistant patients 86(64%) were considered good surgical candidates and 60 underwent epilepsy surgery (76%) being seizure free, after a minimum follow up of one year,42 (70%). Factors related to poor medical control were: younger age at epilepsy onset (p:0.007), longer time of disease duration (p=0.002), greater number of tonic-clonic seizures (GTCG) (p=0.001),losing aura over the time (p=0.017) and remote history of encephalitis (0=0.036). Younger patients (p=0.002) with earlier age at epilepsy onset (p=0.002) whom suffered lower number of GTCG (p=0.042) and with unilateral HS on MRI (p=0.037) were considered good candidates for epilepsy surgery. The best surgery outcome were seen in patients with remote history of febrile seizures (p=0.0008) and longer latent period (p=0.001). Conclusions: Less than 20% of patients with MTLE associated to HS will reach control with medical treatment, approximately 2/3 of the medically resistant patients are good surgical candidates. Older age at epilepsy onset , presence of aura and low number of GTCG are associated with response to medical treatment; history of febrile seizures and longer latent period are associated to good surgery outcome.