Unusual behaviors in sleep as “compensatory” reactions, aimed at normalizing the sleep-wake cycle

Abstract

The present article is an attempt to perform a conceptual clinical and physiological analysis of the large spectrum of sleep-related phenomena called parasomnias in children, based on data from three independent institutions. Parasomnias appear in the process of falling asleep, at the time of sleep stage changes, and upon awakening. They are common for both healthy children and those with neurological and psychiatric disorders. Brief descriptions of clinical pictures of several groups of parasomnias and their polysomnography characteristics are presented. Instances of stereotyped rhythmic movements (e.g. head rocking), paroxysmal somatic and behavioral episodes (night terrors and nightmares), “static” phenomena (sleep with open eyes, strange body positions), as well as somnambulism are specifically described. Common features of parasomnias as a group have been identified (the “Parasomnia syndrome”). It was found that sleep architecture frequently normalizes after a parasomnia episode, whereas parasomniasare spontaneously eliminated after sleep matures (self-cure) or transform into pathology (“inversion”). The significance of gender differences in parasomnias have been reviewed. Possible compensatory physiological functions of parasomnias acting as “switches” or “stabilizers” of sleep stages to “offset” deviated or immature sleep-wake mechanisms are discussed.