Hyperventilation-induced ictal fear in nonlesional temporal lobe epilepsy

Abstract

Hyperventilation is a traditional seizure-provoking procedure used mainly in idiopathic generalized epilepsy and with a relatively limited role in partial epilepsy. Ictal fear is a rare seizure semiology seen in temporal lobe epilepsy. It has been suggested that the amygdala and anterior hippocampus are involved in generating ictal fear. We describe a rare patient with nonlesional temporal epilepsy who, while hyperventilating during an electroencephalography recording, developed complex partial seizures presenting as ictal fear. The particular sensitivity of the anterior hippocampus (probably the amygdala) to hypocapnia might be an important factor contributing to seizures. To avoid misdiagnosing this unusual condition as a pseudo-seizure, a detailed history and seizure semiology, as well as a concurrent electroencephalography recording, are mandatory.