Sudden Unexpected Death in Epilepsy in a Patient with a Responsive Neurostimulator Implant: A Case Report

Introduction: Sudden unexpected death in epilepsy (SUDEP) is the most common cause of epilepsy-related death. Although most witnessed SUDEPs follow seizures, underlying mechanisms are still uncertain. Studies of the pathophysiology of SUDEP have relied on experimental models and rare recordings of brain and body function at the time of the event. The responsive neurostimulation (RNS) device from Neuropace is a deep brain stimulation (DBS) therapy option for drug refractory epilepsy that can both record brain activity and preemptively terminate seizures; as such, patients that experience SUDEP while being treated with a RNS implant can provide valuable information on neural electrophysiological activity at the time of the event.

Methods: We report here the history and electrocortigraphical (ECoG) recordings of a patient with drug refractory epilepsy treated with a RNS device that subsequently experienced SUDEP.

Results: A 19 year old female patient with history of non-verbal autism and Lennox-Gastaut syndrome, a severe childhood epilepsy syndrome commonly presenting with frequent drug-refractory generalized seizures, has RNS placement in the bilateral anterior thalamic nuclei at 14 years of age. She is found by her parents unconscious and in cardiac arrest; while return of spontaneous circulation is achieved enroute to the hospital, return of consciousness is not achieved and the patient passes away. In addition to RNS programming, her anti-seizure medications (ASM) at the time of SUDEP include lamotrigine, topiramate, clobazam, and intranasal diazepam. Later analysis of electrical readings via RNS recordings at time of SUDEP demonstrate seizure onset in the right anterior cingulate lobe and persistence despite multiple RNS seizure termination attempts.

Conclusion : Data on neural function at time of SUDEP is rare in the literature and heterogeneous in reported seizure activity at or preceding the event. Here we present a case of SUDEP associated with onset of ASM- and DBS-refractory seizures. Further use of devices capable of ECoG-monitoring may shed light into the mechanisms underlying SUDEP and possible interventions.