[Geneva-Lausanne laboratory for presurgical epilepsy diagnosis: experiences with the first 150 patients]

In Switzerland there are approximately 35,000 to 70,000 patients who suffer from epilepsy. In 20% of these patients, seizures cannot be satisfactorily suppressed by medical treatment (so-called pharmacoresistent epilepsy); thus surgical therapy represents an alternative. We report on the first 150 patients who have been investigated in the presurgical epilepsy laboratory Geneva-Lausanne since its foundation in April 1995. Of these patients, 75% were adults and 25% were adolescents or infants. In 87% of all patients, non-invasive methods (phase I) were sufficient for diagnosis. In our laboratory, these methods encompassed the following techniques: prolonged video-EEG monitoring, high resolution MRI, positron-emission-tomography (PET), and neurological and neuropsychological exams during the interictal and postictal periods. In 13% of cases, the epileptic focus was localized by intracranial electrodes as well as differentiated against vital cortex (phase II). Of all operated patients, 78% were seizure-free post-operatively, and another 14% significantly ameliorated, such that more than 90% significantly benefited from the intervention. Psychosocial variables (professional, social integration) as changes were also analysed post-operatively. Although the majority of the patients were seizure-free, only 1/4 to 1/3 of all patients showed an improvement in their psychosocial situation. This is most likely due to the long delay between the onset of epilepsy and surgical treatment, which was found to be approximately 10 to 40 years in our patient population. The necessity to pose the diagnosis "pharmacoresistant epilepsy" as fast as possible is discussed, in order to shorten the delay to a few years until a possible operation.