OBJECTIVE Post-stroke epilepsy (PSE) represents a rare etiology in patients undergoing pre-surgical evaluation for epilepsy. Refractory PSE has been traditionally surgically treated with hemispherotomy. The aim of this study was to define the electrophysiological features of epileptogenic zone (EZ) using stereoelectroencephalography (SEEG) recordings in patients with refractory PSE. METHODS We analyzed ictal SEEG recordings from 21 consecutive patients. Epileptogenicity was quantified using the "epileptogenicity index" (EI) method in distant and perilesional cortical structures. We identified different seizure onset patterns (SOP) through a visual and time-frequency analysis. RESULTS We found that 81% of patients showed a complex organization of EZ, involving remote and perilesional structures. EZ involved a significantly (p < 0.01) higher number of distant regions displaying a high epileptogenicity (EI ≥ 0.3). Low voltage fast activity (LFA) and high amplitude slow activity (HAS) patterns were observed respectively in 85.7% and 14.3% of patients. Surgery was proposed in 12/21 patients. Good surgical outcome (Engel Class I or II) was observed for all patients who underwent tailored functional disconnection based on SEEG results. Shorter epilepsy duration to surgery was found in the seizure-free group. SIGNIFICANCE Refractory PSE may present a complex organization of EZ. SEEG recordings are warranted to guide tailored hemispherectomy.
Keywords: Disconnection; Epilepsy surgery; Seizure onset pattern; Stereoelectroencephalography; Stroke.
Copyright © 2019. Published by Elsevier B.V.