Noise characteristics in spaceflight multichannel EEG

Abstract

The cognitive performance of the crew has a major impact on mission safety and success in space flight. Monitoring of cognitive performance during long-duration space flight therefore is of paramount importance and can be performed using compact state-of-the-art mobile EEG. However, signal quality of EEG may be compromised due to the vicinity to various electronic devices and constant movements. We compare noise characteristics between in-flight extraterrestrial microgravity and ground-level terrestrial electroencephalography (EEG) recordings. EEG data recordings from either aboard International Space Station (ISS) or on earth's surface, utilizing three EEG amplifiers and two electrode types, were compared. In-flight recordings showed noise level of an order of magnitude lower when compared to pre- and post-flight ground-level recordings with the same EEG system. Noise levels between ground-level recordings with actively shielded cables, and in-flight recordings without shielded cables, were similar. Furthermore, noise level characteristics of shielded ground-level EEG recordings, using wet and dry electrodes, and in-flight EEG recordings were similar. Actively shielded mobile dry EEG systems will support neuroscientific research and neurocognitive monitoring during spaceflight, especially during long-duration space missions.

Fig 1. Extended 10–20 subset comprising 55 channels contained in and extracted from datasets 1–4.

For datasets 5 and 6, 55 electrode positions of the 256-channel equidistant electrode arrangement with minimum Euclidean distance to the shown 10–20 positions have been analyzed.

Fig 2. Comparison of power spectral density (PSD) between in-flight and ground-level EEG recordings.

Average PSDs of 30 seconds of resting-state EEG data recorded with the MEEMM system during ground-level (pre- and post-flight) and in-flight conditions with a) open eyes, and b) closed eyes of the participants. Solid lines represent mean; dotted lines represent mean + standard deviation.

Fig 3. Comparison of power spectral density (PSD) between unshielded and actively shielded EEG recordings.

Average PSDs of 30 seconds of resting-state EEG data recorded with unshielded (MEEMM, in-flight), and actively shielded gel-based electrode caps (asalab / eego, ground-level) conditions with a) open eyes, and b) closed eyes of the participants. Solid lines represent mean; dotted lines represent mean + standard deviation.

Fig 4. Comparison of power spectral density (PSD) between gel-based and dry EEG recordings.

Average PSDs of 30 seconds of resting-state EEG data recorded with unshielded (MEEMM, in-flight), and actively shielded gel-based and dry electrode caps (eego, ground-level) conditions with a) open eyes, and b) closed eyes of the participants. Solid lines represent mean; dotted lines represent mean + standard deviation.