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Abstract
Hypersynchronous activity (whether hypnagogic or when associated with an arousal) is a common feature in childhood sleep [1]. Monorhythmic and paroxysmal hypnagogic hypersynchrony is most often seen from 3 months to 12 years of age at sleep onset, typically in stage 1. It is characterized by bursts of bisynchronous 75350 V 34.5 Hz waves often maximal in the fronto-central channels [2]. Paroxysms of hypersynchronous theta (47 Hz) and delta (0.52 Hz) waves have also been described as an arousal pattern out of non-rapid eye movement (NREM) sleep in children [3]. If these paroxysms are not accompanied by an increase in EMG tone or a return of the posterior dominant rhythm of wakefulness, it may be difficult to differentiate from an epileptiform discharge.