Ictal semiology in anterior cingulate epilepsy: A systematic review.

Abstract

Seizures originating from the anterior cingulate cortex (ACC) have distinct clinical features but can be difficult to identify in frontal lobe epilepsy (FLE). This systematic review examines the key semiology of ACC seizures and their anatomical correlations. A systematic search was conducted following PRISMA guidelines, including studies reporting ictal semiology, invasive EEG findings, and surgical outcomes in patients with ACC seizures, allowing for the establishment of anatomical and clinical correlations with a high level of confidence. Studies based only on stimulations were excluded. We selected 23 studies including 93 patients (57% males, 46% children). MRI positive (59%), invasive monitoring (74%), surgery (100%) with Engel class I outcome (80%) were the main characteristics. Cortical lesions were found by histology in 86% of the surgical specimen, including focal cortical dysplasia in 67%. The level of confidence in epileptogenic zone (EZ) localization was considered high and very high in 87% of patients. Auras reported by 58% of them mostly included affective (fear or negative emotional feelings) and/or autonomic symptoms (80%). The main ictal signs consisted of facial emotional expressions (46%), autonomic features (48%), vocalization and sudden complex/hypermotor behavior (60%). Spectacular manifestations with preserved awareness, verbalizations with emotional content, laughter, ictal pouting ("chapeau de gendarme") can also point to ACC involvement. In contrast, dystonic/tonic-clonic features, head and eye deviations were less frequently observed (<20%). Loss of consciousness was reported in 35% of patients. Immediate recovery at the seizure-end was usual. Short seizures (<1 min) occurring in clusters during sleep were also characteristics. Combination of these features enhanced the likelihood of ACC origin. Interictal personality disorders which improved after seizure control can be also observed. ACC seizures are predominantly characterized by emotional, autonomic, and striking behavior manifestations contrasting with preserved awareness. These semiology markers support an anatomical and clinical entity and help to localize the EZ in FLE.