Night and day variations of sleep in patients with disorders of consciousness.
Brain injuries substantially change the entire landscape of oscillatory dynamics and render detection of typical sleep patterns difficult. Yet, sleep is characterized not only by specific EEG waveforms, but also by its circadian organization. In the present study we investigated whether brain dynamics of patients with disorders of consciousness systematically change between day and night. We recorded ~24 h EEG at the bedside of 18 patients diagnosed to be vigilant but unaware (Unresponsive Wakefulness Syndrome) and 17 patients revealing signs of fluctuating consciousness (Minimally Conscious State). The day-to-night changes in (i) spectral power, (ii) sleep-specific oscillatory patterns and (iii) signal complexity were analyzed and compared to 26 healthy control subjects. Surprisingly, the prevalence of sleep spindles and slow waves did not systematically vary between day and night in patients, whereas day-night changes in EEG power spectra and signal complexity were revealed in minimally conscious but not unaware patients.
Laboratory for Sleep, Cognition and Consciousness, & Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria.
Malgorzata
http://orcid.org/0000-0001-9272-349X
M
Wislowska
Laboratory for Sleep, Cognition and Consciousness, & Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria.
Renata
R
Del Giudice
Laboratory for Sleep, Cognition and Consciousness, & Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria.
Julia
J
Lechinger
Laboratory for Sleep, Cognition and Consciousness, & Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria.
Tomasz
T
Wielek
Laboratory for Sleep, Cognition and Consciousness, & Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria.
Dominik P J
DPJ
Heib
Laboratory of Image & Data Analysis, Ilixa Ltd., Nottingham, United Kingdom.
Alain
http://orcid.org/0000-0003-0146-8572
A
Pitiot
Apallic Care Unit, Neurological Division, Albert-Schweitzer-Klinik, Graz, Austria.
Gerald
G
Pichler
Apallic Care Unit, Neurological Division, Pflegewohnhaus Donaustadt, Vienna, Austria.
Gabriele
G
Michitsch
Apallic Care Unit, Neurological Division, Pflegewohnhaus Donaustadt, Vienna, Austria.
Johann
J
Donis
Laboratory for Sleep, Cognition and Consciousness, & Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria. Manuel.Schabus@sbg.ac.at.
Manuel
http://orcid.org/0000-0001-5899-8772
M
Schabus
D002940:Circadian Rhythm; D003244:Consciousness Disorders / Q000150:complications*; D004569:Electroencephalography; D006801:Humans; D012890:Sleep; D014851:Wakefulness