Insular interictal positron emission tomography hypometabolism in patients with ictal asystole.

Abstract

We aimed to explore brain area(s) involved in the generation of ictal asystole (IA) by analyzing the interictal positron emission tomography (PET) metabolism of patients with IA recorded by video-electroencephalography or video-stereo-electroencephalography. We identified in our cohort of focal epilepsy patients who had undergone presurgical evaluation those who had a recorded period of IA of more than 3 s. We investigated the anatomometabolic changes (interictal 18 F-fluorodeoxyglucose PET) of these patients in comparison with (1) healthy subjects with similar age and sex distribution (n=19) using whole-brain voxel-based analysis (p-voxel < .001, p-cluster < .05, uncorrected) and (2) patients without IA with similar age and seizure onset zone (n=55). We found 12 patients with IA. Epilepsy was mainly temporal (four right temporal mesial, four bitemporal, two left temporal lateral, one right temporal lateral, and one right temporal "plus"). Seven patients had negative magnetic resonance imaging. Whole-brain statistical analysis of PET imaging was performed at the voxel level, showing that in comparison to healthy subjects and to epileptic patients without IA, a hypometabolism in the right posterior insula characterized epileptic patients with IA. Our study suggests involvement of the right posterior insula-a part of the central autonomic network-in the pathophysiological mechanism of IA.