Abstracts

Rationale: The mechanism of epilepsy in Sturge-Weber syndrome (SWS) has not been elucidated, since it is difficult to detect epileptic discharges on scalp electroencephalography. To determine the pathophysiology of SWS, we evaluated epileptic discharges using intracranial electrocorticography (ECoG). Methods: We recorded intraoperative ECoG in four cases of SWS with entire hemispheric leptomeningeal angioma. We implanted subdural electrodes in one of those cases and monitored prolonged video ECoG. The electrodes were placed upon the surface of the cerebral lobules and the mesial temporal lobe (MTL). We evaluated the IED distributions from both the intraoperative and implanted ECoG, and proved the seizure onset (SO) and propagation from the implanted ECoG. Results: The IEDs were detected from the MTL from both ECoG studies. In the implanted ECoG study, however, the SO was not from the MTL but from the atrophic cerebral hemisphere. The seizure waves were propagated very slowly and lasted for 10 to 30 minutes. Even during the remarkable seizure discharges were seen on the ECoG, the patient did not present noticeable seizure semiology. Conclusions: Although the irritable zone was suspected in the MTL, the SO zone was existed in the atrophic cerebral hemisphere in SWS. The seizure onset zone was not able to detect from the IED distributions. The implanted ECoG is necessary to analyze the epileptogenicity in SWS.