Local sleep-like events during wakefulness and their relationship to decreased alertness in astronauts on ISS

Abstract

Adequate sleep quantity and quality is required to maintain vigilance, cognitive and learning processes. A decrease of sleep quantity preflight and on the International Space Station (ISS) has been reported. Recent counter-measures have been implemented to better regulate sleep opportunities on ISS. In our study, astronauts were allocated enough time for sleep the night before the recordings. However, for proper sleep recovery, the quality of sleep is also critical. Unfortunately, data on sleep quality have yet to be acquired from the ISS. Here, we investigate sleep pressure markers during wakefulness in five astronauts throughout their 6-month space mission by the mean of electroencephalographic recordings. We show a global increase of theta oscillations (5–7 Hz) on the ISS compared to on Earth before the mission. We also show that local sleep-like events, another marker of sleep pressure, are more global in space ( p < 0.001). By analysing the performances of the astronauts during a docking simulation, we found that local sleep-like events are more global when reaction times are slower ( R 2 = 0.03, p = 0.006) and there is an increase of reaction times above 244 ms after 2 months in space ( p = 0.012). Our analyses provide first evidence for increased sleep pressure in space and raise awareness on possible impacts on visuomotor performances in space.

Head-Down Tilt Position, but Not the Duration of Bed Rest Affects Resting State Electrocortical Activity

“…Some technologies are readily commercially available that are lightweight, highly mobile, battery-operated, and allow non-invasive recordings of electrical cortical activity ( Amaral et al, 2017 ; Casson, 2019 ; He et al, 2019 ). EEG recordings in orbit have been successfully employed as part of the Shuttle mission ‘Neurolab’ ( Witten, 2005 ) and the experiment ‘NeuroSpat’ on the ISS ( Cheron et al, 2006 , 2014 ; Cebolla et al, 2016 ; Petit et al, 2019 ). Weightlessness induces a considerable fluid shift to the upper body ( Thornton et al, 1987 ).…”

Changes in performance and bio-mathematical model performance predictions during 45 days of sleep restriction in a simulated space mission

“…In contrast, two separate studies aboard the Space Shuttle (of three and five astronauts) found that crewmembers experienced impaired performance during spaceflight, changes which the authors attributed to fatigue and sleep loss among the crew 3 , 10 . More recent evidence of performance impairment during spaceflight suggest that such changes may relate to a global increase in local sleep-like events during spaceflight compared to on Earth 9 , providing evidence for a relationship between sleep deficiency and performance impairment during spaceflight. Although our data were collected in a spaceflight analogue environment, they suggest that sleep loss during future space missions can be expected to impair performance even among a rigorously selected crew.…”

Sleep in Isolated, Confined, and Extreme (ICE): A Review on the Different Factors Affecting Human Sleep in ICE

“…One recent study conducted on the ISS investigated sleep events during wake (Petit et al, 2019). EEG was not recorded during sleep, but, interestingly, they found that the astronauts involved in a docking simulation task presented increased global theta EEG oscillations while in space than on Earth, and that this increment was associated with slower reaction times.…”