A case of disorder of arousal with prolonged postarousal hypersynchronous delta activity.

Disorder of arousal (DOA) is a form of nonrapid eye movement (NREM) sleep parasomnia caused by partial or incomplete arousal from deep sleep. Most previous studies of DOA patients analyzed prearousal hypersynchronous delta activity (HSDA), but few studies have described postarousal HSDA. Herein, we report a 23-year-old man with a history of abrupt arousal during sleep, confused behavior and speech since he was 14 years old. During video EEG monitoring (VEEG), he had nine arousal events of getting up, sitting on the bed, looking around or simple arousal, including eyes open, looking at the ceiling or head flexion. During all arousal events, the postarousal EEG pattern was prolonged HSDA for approximately 40 seconds. The patient was treated unsuccessfully for more than 2 years with an antiseizure medication (lacosamide); eventually, he responded to clonazepam that was administered for the possibility of DOA. Prolonged rhythmic HSDA without spatiotemporal evolution can appear as a postarousal EEG pattern of DOA. When diagnosing DOA, it is important to recognize that postarousal HSDA can appear as a characteristic EEG pattern of DOA.