The effect of CNS activation versus EEG arousal during sleep on heart rate response and daytime tests

ObjectiveTo induce a heart rate change in normal subjects using auditory stimulation without inducing EEG arousals and to assess the effects on daytime functioning and compare results to auditory stimulation leading to short EEG arousals.MethodsSix normal young men initially randomized into two groups (A and B) underwent 4 nights of nocturnal polysomnography (normal sleep on night 1, auditory stimulation without EEG arousal or normal sleep on nights 2 and 3 using Latin square design, and auditory stimulation with EEG arousal on night 4). MSLT and PVT were performed during days following nights 2–4.ResultsMSLT and PVT results showed significant differences after EEG arousal compared to stimulation without EEG arousal and to normal sleep; there were no significant differences after normal sleep compared to stimulation without EEG arousal. RR interval showed significant differences during undisturbed sleep compared to stimulation without EEG arousal and to stimulation with EEG arousal; RR interval without EEG arousal also differed significantly from RR interval with EEG arousal.ConclusionActivation of the brain-stem can lead to autonomic nervous system (ANS) response without objective consequences the next day.SignificanceANS responses induced by auditory stimulation during sleep without EEG arousal do not have the same effects on daytime sleepiness and performance as sleep fragmentation associated with EEG arousals.