Tailoring epilepsy surgery with fast ripples in the intraoperative electrocorticogram

ObjectiveIntraoperative electrocorticography (ECoG) can be used to delineate the resection area in epilepsy surgery. High‐frequency oscillations (HFOs; 80–500 Hz) seem better biomarkers for epileptogenic tissue than spikes. We studied how HFOs and spikes in combined pre‐ and postresection ECoG predict surgical outcome in different tailoring approaches. MethodsWe, retrospectively, marked HFOs, divided into fast ripples (FRs; 250–500 Hz) and ripples (80–250 Hz), and spikes in pre‐ and postresection ECoG sampled at 2,048 Hz in people with refractory focal epilepsy. We defined four groups of electroencephalography (EEG) event occurrence: pre+post− (+/−), pre+post+ (+/+), pre−post+ (−/+) and pre−post− (−/−). We subcategorized three tailoring approaches: hippocampectomy with tailoring for neocortical involvement; lesionectomy of temporal lesions with tailoring for mesiotemporal involvement; and lesionectomy with tailoring for surrounding neocortical involvement. We compared the percentage of resected pre‐EEG events, time to recurrence, and the different tailoring approaches to outcome (seizure‐free vs recurrence). ResultsWe included 54 patients (median age, 15.5 years; 25 months of follow‐up; 30 seizure free). The percentage of resected FRs, ripples, or spikes in pre‐ECoG did not predict outcome. The occurrence of FRs in post‐ECoG, given FRs in pre‐ECoG (+/−, +/+), predicted outcome (hazard ratio, 3.13; confidence interval = 1.22–6.25; p ...
Source: Annals of Neurology - Category: Neurology Authors: Tags: Research Article Source Type: research