Hypnagogic Behavior Disorder: Complex Motor Behaviors During Wake–Sleep Transitions in 2 Young Children

Abstract

A nondescribed behavioral disorder was observed during wake–sleep transitions in 2 young children. Two boys had episodes of abnormal behavior in hypnagogic—and occasionally hypnopompic—periods for 1 year from the time they were 1 year and several months old. The episodes consisted of irregular body movements, which could be either gentle or violent but never made the children get out of bed. They lasted from a few seconds to 2 hours and were associated with poor reactivity and amnesia of the events. Electroencephalography (EEG) recordings showed wake-state features, with brief bursts of hypnagogic hypersynchrony, and did not display seizure activity. A distinctive behavior disorder occurring during wake–sleep transitions with a wake EEG pattern has been identified in very early childhood. The clinical profile does not fit any of the known parasomnias and might belong to a new category of parasomnia.