Partie d'ouvrage collectif
Résumé : Introduction Electroencephalography (EEG) is a safe and noninvasive brain monitoring modality that measures brain electrical activity and provides reliable and real-time continuous surveillance of electrical neuronal oscillations. The use of EEG in the microgravity environment of space is limited. This study aimed to test and utilize a wireless portable EEG system on astronauts in space to investigate how exposure to the space environment during a short-duration mission may affect the brain’s electrical activity compared to the well-documented waveforms and trends seen in Earth’s gravitational field. A further aim was to evaluate the effects of a short-duration mission and its recovery in comparison to long-duration missions aboard the International Space Station (ISS). Methods This experimental protocol involved data acquisition from one of four astronauts on the Axiom Mission 2 to the ISS. Data was acquired before, during, and directly after a 10-day mission to the ISS with a portable 32-channel EEG device, the Smarting PRO EEG system (mBrainTrain, Belgrade, Serbia). The data was examined in consideration of general signal quality and differences among three distinct conditions: preflight in Earth’s 1G, in-flight in microgravity, and postflight return to Earth’s 1G. Furthermore, to determine the difference between EEG changes in short-duration vs. long-duration spaceflight, we compared the Axiom-2 data with the eyes open resting state condition, which makes part of a more extensive experimental study, Neurospat conducted during five ISS missions of 6 months duration. The significance level was predetermined at p-level < 0.05 for all tests. Results The qualitative analysis of the EEG signals during the preflight, in-flight, and postflight recordings showed no appearance of focal or generalized slow waves or spike activity. All recordings at all three conditions did not show obvious changes in normal awake EEG recordings. Comparing the EEG data from the Axiom-2 study with the eyes open resting state task of the Neurospat experiment, the investigated signal quality was similar. The regions of the Default Mode Network (DMN) showed an alpha band power reduction for two subjects in the Neurospat and the Axiom-2 datasets. The remaining three astronauts in Neurospat, ranging in gender and age, did not show obvious differences across preflight, in-flight, and postflight conditions. All three subjects, with alpha band power reduction, showed a postflight data return to the preflight profile. The calculations of functional connectivity did not reach statistical results, mostly due to the number of electrodes. Conclusion This experiment allowed us to identify that from a qualitative point of view, there are no major clinically significant changes to the brain’s electrical activity of the eyes open resting state during and after a short-duration exposure to microgravity. However, it showed DMN alpha band power differences across conditions in half of the sample (regardless of whether they were involved in short or long missions) that warrant further investigation with a standardized EEG recording protocol. Changes in DMN alpha band power may serve as a potential neurophysiological marker, warranting further research into adaptability mechanisms and mitigation strategies. These findings are of extreme importance to confirm the safety of short-duration spaceflight, especially in the current era of commercial spaceflight. Future studies should consider recordings with a higher number of electrodes, namely, higher spatiotemporal resolution, for a better assessment of functional connectivity.

Documents en relation

DI-fusion