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Sleep. 2017 Feb 1;40(2). doi: 10.1093/sleep/zsw050.

Nocturnal Dynamics of Sleep-Wake Transitions in Patients With Narcolepsy.

Author information

1
Department of Respiratory Medicine, Peking University International Hospital, Beijing, China.
2
Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany.
3
Institute of Physics, Humboldt Universität zu Berlin, Germany.
4
Department of Pulmonary Medicine, Peking University People's Hospital, Beijing, China.
5
Center of Biomedical Image and Information Processing, University of Applied Sciences, Berlin, Germany.
6
Klinik und Poliklinik für Psychiatrie, Psychotherapie und Psychosomatik, Martin-Luther-Universität, Halle (Saale), Germany.
7
Sleep Medicine Center, Charité Universitätsmedizin Berlin, Berlin, Germany.
8
International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic.

Abstract

Introduction:

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.

Aims and Methods:

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).

Results:

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).

Conclusions:

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.

KEYWORDS:

cataplexy; exponential distribution; narcolepsy; power-law distribution; sleep scoring; sleep–wake dynamics; wake-episode durations

PMID:
28364512
DOI:
10.1093/sleep/zsw050
[Indexed for MEDLINE]

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