Prefrontal seizures manifesting as motor stereotypies.

ABSTRACT

BACKGROUND: The definition of stereotypies traditionally does not include "epileptic automatisms." However repetitive, sometimes rhythmic behaviors can occur during frontal lobe seizures in a reproducible pattern for a given patient. Thus, the concept of a frontostriatal "motor loop" could be relevant to repetitive ictal behaviors. METHODS: We describe 17 patients with frontal lobe epilepsy who presented with motor and/or verbal stereotypies and who were explored using depth electrodes (stereoelectroencephalography [SEEG]) in the context of epilepsy presurgical evaluation. RESULTS: Motor patterns were typically reproducible between seizures for a given patient. Distal motor stereotypies were associated with anterior prefrontal localization, and proximal stereotypies were associated with posterior prefrontal localization. CONCLUSIONS: "Stereotypy" is a useful term to describe ictal repetitive behaviors produced by prefrontal seizure discharge. The expression of distal and proximal stereotypies follows a rostrocaudal gradient within the frontal lobes. Exploration of the cortical compartment of frontostriatal networks in epileptic patients offers a unique opportunity to study the mechanisms of stereotypies in vivo.