Primarily generalized seizures are more effective than partial seizures in arousing patients from sleep

The purpose of this study was to determine the characteristics of generalized and partial seizures which awaken patients from sleep, using a retrospective review of intracranial EEG recordings in 8017 electrographic and 7571 clinical seizures in 172 patients undergoing evaluation for epilepsy brain surgery. Seizure onset during sleep followed by awakening occurred in 99% of 308 seizures in 22 patients during daytime naps. Four events consisted of spontaneous awakening followed by the seizure. In contrast electrographic seizures almost never awakened the patient if they were partial in onset (0.02% temporal, 0% frontal), but did so 26% of the time if they were generalized (p < 0.001). Conversely, generalized clinical seizures awakened the patient only 0.3% of the time (p < 0.001) versus 3% for temporal and 6% for frontal lobe. Partial and generalized seizures differ during sleep. Partial seizures do not awaken until they propagate outside the lobe and evolve into a clinical seizure. Generalized seizures when only electrographic, include wake-regulating structures at their onset (presumably thalamus, hypothalamus, brainstem). Our results suggest that rather than sleep transitions being a facilitatory cause of seizures, seizures awaken us from sleep via endogenous stimulation of the brain's sleep/wake structures. This pathway information may be relevant to planning epilepsy brain surgery.