title: Daytime sleepiness and neural cardiac modulation in sleep-related breathing disorders.
abstract: Sleep-related breathing disorders are common causes of excessive daytime sleepiness, a socially and clinically relevant problem. Mechanisms responsible for daytime sleepiness are still largely unknown. We investigated whether specific alterations in autonomic cardiac modulation during sleep, commonly associated with sleep-related breathing disorders, are related to excessive daytime sleepiness. Fifty-three patients with sleep-related breathing disorders underwent nocturnal polysomnography. Excessive daytime sleepiness was diagnosed as a Multiple Sleep Latency Test response less than or equal to 600 s. We explored the relation of excessive daytime sleepiness, objectively determined, with indices of autonomic cardiac regulation, such as baroreflex sensitivity and heart rate variability, with polysomnographic indices of the severity of sleep-related breathing disorders and with quality of sleep. Patients with excessive daytime sleepiness, when compared with patients without, had significantly lower baroreflex sensitivity and significantly higher low-to-high frequency power ratio of heart rate variability during the different stages of nocturnal sleep. By contrast, no differences were found in indices quantifying the severity of sleep-related breathing disorders or sleep quality. We demonstrated that excessive daytime sleepiness is accompanied by a deranged cardiac autonomic control at night, the latter probably reflecting autonomic arousals not detectable in the EEG. As abnormal autonomic regulation is also known to be associated with increased cardiovascular risk, a possible relation between excessive daytime sleepiness and cardiovascular events in patients with sleep-related breathing disorders deserves to be investigated in future studies.
authors.affiliation: Center for Sleep Disorders, Department of Neurological Sciences, University of Bologna, Bologna, Italy.
authors.forename: Carolina
authors.initials: C
authors.lastname: Lombardi
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Parati
authors.forename: Pietro
authors.initials: P
authors.lastname: Cortelli
authors.forename: Federica
authors.initials: F
authors.lastname: Provini
authors.forename: Roberto
authors.initials: R
authors.lastname: Vetrugno
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Plazzi
authors.forename: Luca
authors.initials: L
authors.lastname: Vignatelli
authors.forename: Marco
authors.initials: M
authors.lastname: Di Rienzo
authors.forename: Elio
authors.initials: E
authors.lastname: Lugaresi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Mancia
authors.forename: Pasquale
authors.initials: P
authors.lastname: Montagna
authors.forename: Paolo
authors.initials: P
authors.lastname: Castiglioni
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology; D001341:Autonomic Nervous System / Q000503:physiopathology*; D017704:Baroreflex / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D005583:Fourier Analysis; D006321:Heart / Q000294:innervation*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012016:Reference Values; D012815:Signal Processing, Computer-Assisted; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000503:physiopathology*; D012894:Sleep Stages / Q000502:physiology; D012913:Snoring / Q000503:physiopathology