Hypnagogic Hypersynchrony
Hypnagogic Hypersynchrony
Hypnagogic Hypersynchrony
Pediatric EEG’s often have a higher amplitude than adults, and their sleep architecture can be more pronounced or exaggerated. Hypnagogic hypersynchrony was first termed in 1950 by Gibbs and occurs at sleep onset or drowsiness in children. This pattern is characterized by a dramatic burst of paroxysmal high-amplitude theta-delta frequency slowing of 3- to 5-Hz with amplitudes as high as 300μV or more. These bursts may become longer in duration as drowsiness deepens. The hypnagogic hypersynchronous pattern is most prominent around the age of 1 year, decreases toward the age of 10 years and is a normal finding in children associated with drowsiness.
Similar hypersynchronous theta bursts may occur intermittently associated with brief arousal from light sleep. The children also show similar but less rhythmic theta–delta bursts upon arousal, called hypnopompic hypersynchrony. This lasts from a few seconds to a few minutes, depending on how sleepy the child is upon awakening from sleep.