Do the EEG and behavioral criteria of NREM arousal disorders apply to sexsomnia?

Study Objectives To establish whether the recent EEG and behavioral criteria of arousal disorders apply to sexsomnia. Methods EEG and behavioral markers upon N3 sleep interruptions in videopolysomnography were retrospectively compared in 24 participants with sexsomnia, 41 participants with arousals disorders, and 40 healthy controls. The specificity and sensitivity of previously suggested EEG and behavioral cutoffs for supporting arousal disorders diagnosis were measured in the sexsomnia vs. control groups. Results Participants with sexsomnia and arousals disorders showed a higher N3 fragmentation index, slow/mixed N3 arousal index, and number of eye openings during N3 interruptions than healthy controls. Ten (41.7%) participants with sexsomnia (vs. one sleepwalker and no control) displayed an apparently sexual behavior (masturbation, sexual vocalization, pelvic thrusting, and hand within the pajama) during N3 arousal. An N3 sleep fragmentation index ≥6.8/h of N3 sleep and two or more N3 arousals associated with eye opening was 95% specific but poorly (46% and 42%) sensitive for diagnosing sexsomnia. An index of slow/mixed N3 arousals ≥2.5/h of N3 sleep was 73% specific and 67% sensitive. An N3 arousal with trunk raising, sitting, speaking, showing an expression of fear/surprise, shouting, or exhibiting sexual behavior was 100% specific for a diagnosis of sexsomnia. Conclusions In patients with sexsomnia, videopolysomnography based markers of arousal disorders are intermediate between healthy individuals and patients with other arousal disorders, supporting the concept of sexsomnia as a specialized, but less neurophysiologically severe, NREM parasomnia. Previously validated criteria for arousal disorders partially fit in patients with sexsomnia.