Intracranial electroencephalography seizure onset patterns and surgical outcomes in nonlesional extratemporal epilepsy

A focal high-frequency oscillation (> 20 Hz) at seizure onset on iEEG may identify patients with nonlesional extratemporal epilepsy who are likely to have an Engel Class I outcome after epilepsy surgery. The prospect of excellent outcome in nonlesional extratemporal lobe epilepsy prior to intracranial monitoring is poor (14 [27.5%] of 51 patients). However, iEEG can further stratify patients and help identify those with a greater likelihood of Engel Class I outcome after surgery.