Cortical thinning in epilepsy patients with postictal generalized electroencephalography suppression

Background and purpose The aim was to investigate the brain microstructural abnormalities in epilepsy patients with postictal generalized electroencephalographic suppression (PGES) using a cortical surface-based analysis. Methods According to the video-electroencephalography records of epilepsy patients with generalized convulsive seizures, 30 patients with PGES (PGES+) and 21 patients without PGES (PGES-) were recruited. High-resolution T1-weighted images were acquired from each patient and 30 matched healthy control subjects. Cortical thickness was compared amongst the three groups using FreeSurfer software. Results Patients with PGES showed reduced cortical thickness in the right paracentral lobule, inferior parietal lobule, supramarginal gyrus and middle temporal lobe compared with patients without PGES. In relation to healthy control subjects, the PGES+ group presented reduced cortical thickness in the right superior parietal lobule and supramarginal gyrus, whilst the PGES- group presented reduced cortical thickness in the left precuneus, precentral gyrus, lateral occipital gyrus, parahippocampal gyrus, superior parietal lobule and right caudal middle frontal gyrus. Conclusions Patients with PGES exhibited characteristic brain microstructural abnormalities, corroborating the PGES mechanisms at the brain level. The right-sided predominance of the detected PGES-related cortical thinning was the same as that of sudden unexpected death in epilepsy (SUDEP) cases and patients at high risk for SUDEP, implying that PGES and SUDEP may share a common abnormal brain substrate that is involved in the pathophysiology of these conditions.