Sleep-related hypermotor epilepsy activated by rapid eye movement sleep

Most sleep-related seizures occur during non-rapid eye movement (NREM) sleep, particularly during stage changes. Sleep-related hypermotor epilepsy (SHE) is a rare epileptic syndrome characterized by paroxysmal motor seizures, mainly arising from NREM sleep. Here, we report a patient with SHE who had seven seizures captured on video-EEG-polysomnography during REM sleep. Ictal semiology of this patient ranged from brief paroxysmal arousals to hypermotor seizures. On EEG-polysomnography, the spontaneous arousals were more frequent during REM than NREM sleep, with a considerably higher arousal index in REM sleep (20/ hour). While the reason for seizures during REM sleep in this patient is unclear, we speculate that the threshold and mechanisms of arousal during different sleep stages may be related to the occurrence of seizures. [Published with video sequences on www.epilepticdisorders.com].