Surgical outcome and prognostic factors of cryptogenic neocortical epilepsy

Abstract

Surgical treatment of cryptogenic neocortical epilepsy is challenging. The aim of this study was to evaluate surgical outcomes and to identify possible prognostic factors including the results of various diagnostic tools. Eighty-nine patients with neocortical epilepsy with normal magnetic resonance imaging (35 patients with frontal lobe epilepsy, 31 with neocortical temporal lobe epilepsy, 11 with occipital lobe epilepsy, 11 with parietal lobe epilepsy, and 1 with multifocal epilepsy) underwent invasive study and focal surgical resection. Patients were observed for at least 2 years after surgery. The localizing values of interictal electroencephalogram (EEG), ictal scalp EEG, interictal 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), and subtraction ictal single-photon emission computed tomography were evaluated. Seventy-one patients (80.0%) had a good surgical outcome (Engel class 1-3); 42 patients were seizure free. Diagnostic sensitivities of interictal EEG, ictal scalp EEG, FDG-PET, and subtraction ictal single-photon emission computed tomography were 37.1%, 70.8%, 44.3%, and 41.1%, respectively. Localization by FDG-PET and interictal EEG was correlated with a seizure-free outcome. The localizing value of FDG-PET was greatest in neocortical temporal lobe epilepsy. The focalization of ictal onset and also ictal onset frequency in invasive studies were not related to surgical outcome. Concordance with two or more presurgical evaluations was significantly related to a seizure-free outcome.

The Utility of Positron Emission Tomography in Epilepsy

“…Of these studies, 12 were retrospective [8][9][10][11][12][13][14][15][16][17][18][19] and one was part of a prospective observational study. 45 Good surgical outcome was considered in patients with Engel class I, II, or III.…”

Imaging haemodynamic changes related to seizures: Comparison of EEG-based general linear model, independent component analysis of fMRI and intracranial EEG

“…Given that ictal EEG does not always reflect seizure onset (Binnie and Stefan, 1999) providing localising information in 13-92% of patients (Blume, 2001;Foldvary et al, 2001;Lee et al, 2005), data driven analysis of fMRI (i.e. without modelling the EEG) may be helpful.…”

Deep brain stimulation for medically refractory epilepsy

“…An average reduction in seizure frequency of 67% (range 44-94%), was noted during the sham interval. Once the stimulators were turned on, a 49% (range 35-76%) reduction in seizure frequency was noted over the subsequent follow-up period (mean 43.8 months, range [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. In 1 patient the stimulator was inadvertently turned off during months 7-12, during which period the seizure frequency increased compared to baseline.…”

“…9 Treatment options for these patients include new AEDs, which may lead to seizure freedom in 7% of patients, 22 and resection, which is associated with long-term seizure freedom in 60-80% of patients. 19,46 Surgery in patients whose epilepsy has proven refractory to AEDs provides a high likelihood of reduction in seizure frequency, is generally safe, and is recommended in selected patients with refractory partial seizures. In spite of improvements in surgical technique, ~ 4% of patients will suffer death or permanent neurological disability afterwards.…”