A Possible Mechanism for Sudden Unexpected Death in Epilepsy
Recently, Dr. Hiro Otsubo presented his work on Sudden Unexpected Death in Epilepsy (SUDEP) at one of our weekly EpLink Fellows’ Meetings. SUDEP is defined as the death of an otherwise healthy individual with epilepsy that occurs either immediately after a seizure or even when there is no recent evidence of seizure activity. Dr. Otsubo’s findings suggest a possible mechanism for SUDEP following a tonic-clonic (grand mal) seizure.
After a tonic-clonic seizure, there is usually a period of lowered brain activity. Researchers can measure this brain activity with a technique called electroencephalography (EEG), and what they see on an EEG recording is a “flattening” of the brain activity after a tonic-clonic seizure, when the person is unconscious. This period of flattened EEG has been called “Postictal-Generalized EEG Suppression” or “PGES”. Normally, PGES passes without incident, and the patient regains consciousness shortly after the seizure is over.
Dr. Otsubo believes, however, that after a very strong tonic-clonic seizure, a deep and prolonged PGES can occur, and that this can stop an individual’s breathing and result in death. Such a PGES can occur even in patients who otherwise show normal brain activity, as measured by EEG.
Dr. Otsubo’s findings provide a potential way to identify patients at risk for SUDEP. Individuals at risk would be those who show long and pronounced EEG flattening after tonic-clonic seizures. Seizures in these patients should be monitored carefully, and – if at all possible – controlled.