Parasomnias: Lots of emotional faces, negative speech, worries, profanities, insults; smiling sleep is rare in these adults

Parasomnia: a window into dreaming process? Isabelle Arnulf. Keynote to International Association for the Study of Dreams' June 2019 Conference. http://iasdconferences.org/2019/wp-content/uploads/2019/04/2019-Abstracts-Final.pdf

Abstract: The parasomnias include sleep talking (REM and NREM sleep), sleepwalking, night terrors (NREM sleep) and REM sleep behavior disorder (RBD), sleep-related hallucinations and sleep paralysis (REM sleep). Many can cause injuries and sleep disturbances, thereby needing to be diagnosed and treated. Of note, sleep talking, sleepwalking and RBD correspond to dream-enacted behaviors, thanks to isomorphism between behaviors and later dream recall. The gestures, speeches and facial expressions of the dreamers render the dreaming scenario visible for external observers. We first performed an ethological repertory of all visible behaviors, speeches and, more recently, emotional face expressions, in RBD and sleepwalking in a large (>200 subjects) adult cohort. Aggression by animals and humans predominated in RBD (the dreamer counterattacking the aggressor) whereas natural catastrophes predominated in sleepwalking/night terror (the dreamer trying to escape the imminent danger by running away), suggesting a “flight (NREM) and fight (REM)” answer to threat simulation. Similarly, the sleep-associated speeches (whether in genuine sleep talkers or in patients with RBD and sleepwalking) were mostly negative, worried, and repeated. Verbal violence (more frequent in male sleep talkers) contained more profanities in NREM sleep and insults in REM sleep. However, non-violent, elaborate behaviors and speeches were also visible, although less frequent than violent ones. Smiling asleep was rare in normal adults, but quite frequent in RBD patients. This narrow but fascinating window helped test some hypotheses about dreaming, including which motor and verbal systems are at play during dreaming, whether episodic memories are included into the nocturnal behaviors, whether the eyes scan the dream scenario during REM sleep, whether non-dreamers do not dream or do not recall their dreams, without the bias of dream recall.