Abstracts

RATIONALE: The aim of this work was to evaluate the contribution of the equivalent source models of paroxysmal interictal activities (PIA) in epileptic patients (27) candidate for surgery. We particularly focused on the practical use of realistic head model compared to the spherical head model METHODS: Surface EEG (32 or 64 electrodes) was recorded in order to collect PIA. Electrodes positions were digitized and used to generate a spherical head model or matched to the realistic head model semi automatically generated from the patient MRI. Single equivalent current dipole (ECD; ASA software) was applied and retained when the fit was sufficient over a certain period of time. RESULTS: None of our patients with medial temporal lobe epilepsy had PIA. For others types, the ECD location was in agreement with epileptogenic area hypothesis. ECD with realistic and spherical models were separated by 3 to 15 mm. This difference was maximal for lateral temporal lobe epilepsies. CONCLUSIONS: Dipole source analysis of PIA provides relevant information during presurgical study. In our preliminary results, the realistic model with single ECD did not provide significant difference and may not justify the extrawork required. These results need further validation with SEEG data and may be revisited with more complex source models.