Abstracts

Rationale: Surgery is an important treatment option for refractory temporal lobe epilepsy (TLE), relieving patients from disabling seizures in 58% (Engel Ia). Several causes have been identified to explain temporal lobe surgery failures or why successful cases cannot be weaned completely off antiepileptic drugs. Recent evidence suggest that failure to recognize insular seizures could explain part of these failures. Insular cortex epilepsy should be suspected when viscerosensitive, motor and especially somatosensory symptoms (SSS) are combined early in the attack. We sought to determine the prevalence and prognostic value of early SSS in patients with refractory TLE. Methods: We performed a retrospective chart analysis of patients who underwent temporal lobe surgery for refractory epilepsy at Notre-Dame Hospital from September 2000 to October 2007. Each patient underwent a comprehensive epilepsy surgical workup. Collected data included duration of epilepsy, seizure type, frequency and semiology, results from preoperative investigations, type of surgery and outcome. Particular attention was put on the presence of early SSS. Results: Fifty-one patients underwent temporal lobectomy for drug-resistant TLE (26 males). Mean duration of epilepsy was 18,9 yrs and mean age at surgery was 39,7 years. There were 21 anterior temporal lobectomies (ATL), 23 selective amygdalo-hippocampectomies (SAH), 5 lesionectomies , and 2 ATL plus insulectomy. Hippocampal sclerosis was diagnosed at pathology either alone (n=34) or with other diagnosis (n=4). Other pathologies included cavernoma (n=2), astrocytoma (n=1), FCD (n=2), DNET (n=1), cortical gliosis (n=2) or were non-conclusive (n=5). Eleven (21,5%) patients reported experiencing early somatosensory symptoms during their seizures. Engel 1a outcome was achieved in 53% of cases overall (n=27 of 51), 33% in the group with early SSS (n=3 out of 9), 57,5% in the group without early SSS (n=23 of 40), and 100% in the group with early SSS with additional insulectomy (n=2 of 2). Conclusions: These preliminary observations suggest that the presence of early ictal SSS in apparent refractory TLE predicts a poorer surgical outcome. Potential explanations include unrecognized insular or parietal lobe seizures.