title: Nocturnal Dynamics of Sleep-Wake Transitions in Patients With Narcolepsy.
abstract: We investigate how characteristics of sleep-wake dynamics in humans are modified by narcolepsy, a clinical condition that is supposed to destabilize sleep-wake regulation. Subjects with and without cataplexy are considered separately. Differences in sleep scoring habits as a possible confounder have been examined.
  
  
  
  Four groups of subjects are considered: narcolepsy patients from China with (n = 88) and without (n = 15) cataplexy, healthy controls from China (n = 110) and from Europe (n = 187, 2 nights each). After sleep-stage scoring and calculation of sleep characteristic parameters, the distributions of wake-episode durations and sleep-episode durations are determined for each group and fitted by power laws (exponent α) and by exponentials (decay time τ).
  
  
  
  We find that wake duration distributions are consistent with power laws for healthy subjects (China: α = 0.88, Europe: α = 1.02). Wake durations in all groups of narcolepsy patients, however, follow the exponential law (τ = 6.2-8.1 min). All sleep duration distributions are best fitted by exponentials on long time scales (τ = 34-82 min).
  
  
  
  We conclude that narcolepsy mainly alters the control of wake-episode durations but not sleep-episode durations, irrespective of cataplexy. Observed distributions of shortest wake and sleep durations suggest that differences in scoring habits regarding the scoring of short-term sleep stages may notably influence the fitting parameters but do not affect the main conclusion.
authors.affiliation: Department of Respiratory Medicine, Peking University International Hospital, Beijing, China.
authors.forename: Xiaozhe
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany.|Institute of Physics, Humboldt Universität zu Berlin, Germany.
authors.forename: Jan W
authors.initials: JW
authors.lastname: Kantelhardt
authors.affiliation: Department of Pulmonary Medicine, Peking University People's Hospital, Beijing, China.
authors.forename: Xiao Song
authors.initials: XS
authors.lastname: Dong
authors.affiliation: Center of Biomedical Image and Information Processing, University of Applied Sciences, Berlin, Germany.
authors.forename: Dagmar
authors.initials: D
authors.lastname: Krefting
authors.affiliation: Department of Pulmonary Medicine, Peking University People's Hospital, Beijing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Pulmonary Medicine, Peking University People's Hospital, Beijing, China.
authors.forename: Han
authors.initials: H
authors.lastname: Yan
authors.affiliation: Klinik und Poliklinik für Psychiatrie, Psychotherapie und Psychosomatik, Martin-Luther-Universität, Halle (Saale), Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Pillmann
authors.affiliation: Sleep Medicine Center, Charité Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Ingo
authors.initials: I
authors.lastname: Fietze
authors.affiliation: Sleep Medicine Center, Charité Universitätsmedizin Berlin, Berlin, Germany.|International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic.
authors.forename: Thomas
authors.initials: T
authors.lastname: Penzel
authors.affiliation: Department of Pulmonary Medicine, Peking University People's Hospital, Beijing, China.
authors.forename: Long
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Pulmonary Medicine, Peking University People's Hospital, Beijing, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Han
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002385:Cataplexy / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009290:Narcolepsy / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D012890:Sleep / Q000502:physiology; D012894:Sleep Stages / Q000502:physiology*; D055815:Young Adult
keywords: cataplexy; exponential distribution; narcolepsy; power-law distribution; sleep scoring; sleep–wake dynamics; wake-episode durations