Ictal nausea and vomiting - Is it left or right?

PURPOSE:Ictal nausea/vomiting has been linked to the non-dominant hemisphere and has been considered a lateralizing sign. However, small case series and single cases have reported seizure localisation in the dominant hemisphere. Here we aimed to determine the seizure localisation and lateralization in cases with ictal nausea/retching/vomiting to test the hypothesis that these signs are of lateralizing value. METHODS:We searched two large tertiary epilepsy-center video-EEG databases (period: 1980-2017) for reports on ictal nausea/retching/vomiting and retrieved ictal EEG seizure location, lateralization and clinical symptoms. RESULTS:We identified 13 patients with focal epilepsy and video-EEG-documented ictal nausea (n = 2), nausea and retching (n = 3), retching followed by vomiting (n = 5) or only vomiting (n = 3). Aetiology was genetic (n = 1), structural/metabolic (n = 7) or of unclear origin (n = 5). While in 12/13 patients epileptic discharges were temporal, a single case was parietal. A left-sided seizure origin was more frequent than a right-sided origin (62 vs. 38%). Assuming a left-sided language dominance in the single left-handed patient and in those two patients with unclear handedness (based on the known distribution of hemispheric speech-dominance), the distribution of ictal nausea/retching/vomiting to the dominant vs. non-dominant hemisphere was not significantly different from a random distribution (8 vs. 5, p = 0.581). CONCLUSION:Ictal nausea/retching/vomiting are most frequently of temporal origin. In contrast to previous studies, our ictal video-EEG data suggests that these signs have no lateralizing value. Thus, video-EEG should be performed and while this clinical sign points to a temporal seizure origin, it does not determine its lateralization.