Premium
Interindividual differences in the dynamics of the homeostatic process are trait‐like and distinct for sleep versus wakefulness
Author(s) -
Rusterholz Thomas,
Tarokh Leila,
Van Dongen Hans P. A.,
Achermann Peter
Publication year - 2017
Publication title -
journal of sleep research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 117
eISSN - 1365-2869
pISSN - 0962-1105
DOI - 10.1111/jsr.12483
Subject(s) - wakefulness , sleep (system call) , psychology , intraclass correlation , trait , slow wave sleep , correlation , sleep onset , audiology , developmental psychology , neuroscience , electroencephalography , medicine , insomnia , mathematics , psychiatry , psychometrics , geometry , computer science , programming language , operating system
Summary The sleep homeostatic Process S reflects the build‐up of sleep pressure during waking and its dissipation during sleep. Process S is modelled as a saturating exponential function during waking and a decreasing exponential function during sleep. Slow wave activity is a physiological marker for non‐rapid eye movement (non‐ REM ) sleep intensity and serves as an index of Process S. There is considerable interindividual variability in the sleep homeostatic responses to sleep and sleep deprivation. The aim of this study was to investigate whether interindividual differences in Process S are trait‐like. Polysomnographic recordings of 8 nights (12‐h sleep opportunities, 22:00–10:00 hours) interspersed with three 36‐h periods of sustained wakefulness were performed in 11 healthy young adults. Empirical mean slow wave activity per non‐ REM sleep episode at episode mid‐points were used for parameter estimation. Parameters of Process S were estimated using different combinations of consecutive sleep recordings, resulting in two to three sets of parameters per subject. Intraclass correlation coefficients were calculated to assess whether the parameters were stable across the study protocol and they showed trait‐like variability among individuals. We found that the group‐average time constants of the build‐up and dissipation of Process S were 19.2 and 2.7 h, respectively. Intraclass correlation coefficients ranged from 0.48 to 0.56, which reflects moderate trait variability. The time constants of the build‐up and dissipation varied independently among subjects, indicating two distinct traits. We conclude that interindividual differences in the parameters of the dynamics of the sleep homeostatic Process S are trait‐like.