The role of the anterior insular cortex in ictal vomiting: a stereotactic electroencephalography study

Ictal vomiting is a rare manifestation most often associated with right temporal lobe epilepsy. The implication of the anterior insula in the occurrence of this symptom has been suggested based on the role of this region in swallowing and on the observation that electrical insular stimulation can elicit nausea and vomiting. We report the first case, to our knowledge, of a patient presenting with ictal vomiting who underwent bilateral intracranial exploration including insular depth electrodes. The seizure onset zone was localized in the left temporomesial structures, but the occurrence of ictal vomiting correlated in time with a discharge affecting exclusively the anterior part of both insular lobes. It is concluded that the occurrence of ictal vomiting reflects a propagation of the discharge to the insular cortex. Observation of this symptom at the very onset of the seizures in a patient with temporal lobe epilepsy is highly suggestive of an insular seizure onset zone.