The localizing value of mimic ictal semiology: A systematic review of the spectrum.

Abstract

We performed a systematic review of the localization value of ictal mimic automatisms-including gelastic, dacrystic, fearful, ritualistic, and kissing semiology-in focal epilepsy. We performed a comprehensive literature search (Medline, EMBASE, Cochrane, Scopus) for patient-level studies, following a PRISMA and QUADAS2 approach. Patients with focal epilepsy displaying mimic automatism, defined as "stereotyped mimicry or behavior that resembles the usual way one expresses oneself to reflect an affect and that is not accompanied by the corresponding emotion" were included. Patients with subjective emotional experiences during a seizure, which the patient is aware of, were excluded. Analysis included 936 patients from 104 studies. Gelastic semiology was primarily associated with hypothalamic hamartomas (HH), and secondarily with frontal (cingulate; superior frontal gyrus), temporal (hippocampus; amygdala; pole; parahippocampal and fusiform gyri), insular, and orbitofrontal involvement, without consistent hemispheric lateralization. Dacrystic semiology was associated with HH, as well as temporal lobe seizure onset (mesial and anterior), followed by the less frequent involvement of orbitofrontal (anterior; baso-lateral), insular, and frontal regions; also without consistent hemispheric lateralization. Fearful ictal semiology was equally associated with frontal (cingulate; superior frontal gyrus), orbitofrontal (mesial; posterior), and temporal (hippocampus; amygdala) involvement; most often, but not exclusively, of right hemispheric lateralization. Ritualistic behavior was associated with the temporal lobe origin (hippocampus; amygdala; pole), with strong right hemispheric lateralization. Kissing ictal behavior was associated with temporal lobe origin (pole; hippocampus; amygdala), and secondarily with the frontal lobe (cingulate); most often, but not exclusively, of right hemispheric lateralization. Our systematic review-derived localization of the various manifestations of mimic automatisms supports anatomo-clinical correlations and helps guide interpretation of ictal semiology within the framework of pre-surgical evaluation in focal epilepsies.