Associations of waking EEG structure with chronotype and trototype of 130 sleep deprived individuals

Abstract

We explored the relationship between inter-individual variation in waking EEG spectra and trait-like variation in sleep–wake adaptability. Resting EEG was recorded every three hours (nine times) in the course of sustained wakefulness of 130 healthy subjects. EEG powers were averaged across 10 frequency ranges (from slow delta to slow gamma) and further reduced by performing principal component analysis. It yielded the subjects' scores on three largest principal components (PCs) with eigenvalues greater or approximately equal to 1. These PCs were interpreted as EEG amplifying (#1), EEG slowing (#2), and EEG smoothing (#3). PC#1 score correlated with sleep debt (i.e. self-reports on sleep restriction in the morning preceding the experiment) and with the corresponding sleep–wake traits (i.e. lateness scores reflecting subjects' chronotype). PC#2 score was related to sleep pressure (i.e. perceived increase in sleepiness caused by sleep deprivation) and to the corresponding sleep–wake adaptabilities (i.e. wakeability scores reflecting subjects' trototype).

Keywords:

• sleep deprivation
• sleep restriction
• sleepiness
• sleep homeostasis
• circadian process
• sleep–wake adaptability

Acknowledgements

This study was supported by grant number 06-06-00375a from the Russian Humanitarian Science Foundation and by grant number 07-06-00263а from the Russian Foundation for Basic Research.