As humanity enters the era of long‑term crewed deep‑space exploration, understanding the brain’s adaptive mechanisms to extreme environments such as microgravity and radiation has become a critical issue in space medicine. Previous studies using magnetic resonance imaging have revealed structural brain plasticity after spaceflight, including ventricular expansion and changes in grey matter volume. However, knowledge of dynamic changes at the neurophysiological level remains limited, and most existing evidence comes from group‑level analyses of long‑duration missions (e.g., six months), leaving the specific neurofunctional impact of short‑duration missions on individuals unclear. Conventional neuroimaging equipment is bulky and cannot be used in orbit. In contrast, electroencephalography (EEG) is portable, low‑cost, and repeatable, and has shown sensitivity in neurological conditions such as concussion, but its application in the extreme spaceflight environment has not been reported. Therefore, validating the feasibility of portable EEG technology for monitoring individual brain function before and after short‑duration spaceflight holds significant practical value for building future in‑orbit brain health assessment systems in deep‑space exploration.
In a recent study published in Space: Science & Technology , a research team from Simon Fraser University and the University of Calgary, for the first time, adopted the brain vital signs framework to monitor cognitive and neurophysiological function in astronauts participating in a 17‑day mission to the International Space Station. Data were collected at three time points: preflight, 7–11 days after landing (postflight 1), and 154–177 days after landing (postflight 2). The assessments included the Cogstate neuropsychological test battery and auditory event‑related potentials (ERPs) recorded via EEG. Standard/deviant auditory tones were used to elicit the N100 and P300 components, while semantically congruent/incongruent word pairs elicited the N400 component. Differences in ERP waveforms across time points were compared using Morlet wavelet time‑frequency analysis and cluster‑based permutation testing. The results showed minimal differences in accuracy and reaction time across various cognitive tasks for both astronauts, with only one task showing a drop of less than 10% for a single participant. In both the time and time‑frequency domains, no significant differences were found between waveforms elicited by deviant tones or incongruent word pairs across time points, and the latencies and amplitudes of N100, P300, and N400 remained stable. In contrast to persistent changes in visual ERPs reported after long‑duration missions, this 17‑day short‑duration mission revealed no significant neurophysiological decline, likely because short‑duration missions induce more subtle and more rapidly resolving structural brain changes. This study provides the first validation of the feasibility of the brain vital signs framework for rapid, repeatable monitoring of individual brain function in the extreme operational environment of spaceflight. It lays an important methodological foundation and offers preliminary evidence for future in‑orbit EEG monitoring, individualised neurofunctional tracking, and investigations into the effects of different mission durations on brain function.
This study focuses on the effects of short‑duration spaceflight on astronauts' cognitive and neurophysiological function, and for the first time employs a portable EEG‑based brain vital signs framework for individual‑level monitoring. In the space environment, stressors such as microgravity and radiation may induce structural and functional brain changes; however, previous research has largely relied on large‑scale neuroimaging equipment like MRI, which cannot be used in orbit, and group‑level analyses of long‑duration missions (e.g., six months) have been insufficient to reveal the dynamic neuroelectrophysiological changes in individuals during short‑duration missions. To address this, the study recruited two astronauts participating in a 17‑day mission to the International Space Station and collected data at three time points: approximately 40 days before launch, about 10 days after landing, and roughly 160 days after landing. Neuropsychological assessment was performed using the Cogstate test battery, covering domains such as executive function, processing speed, memory, attention, and social‑emotional cognition. EEG data were acquired using an 8‑channel wireless system, and the brain vital signs framework employed standard and deviant auditory tones to elicit N100 and P300 components, along with semantically congruent and incongruent word pairs to elicit the N400 component, with each test lasting only 6 minutes. Although this framework has demonstrated sensitivity in neurological conditions like concussion, its application in the spaceflight environment is reported here for the first time.
Secondly, the results showed that both astronauts' cognitive task performance and EEG event‑related potentials remained stable across pre‑ and post‑flight time points. Table 1 presents the accuracy and error counts for the neuropsychological tests, with the vast majority of tasks showing minimal differences across the three time points; only one participant exhibited a drop of less than 10% in accuracy on a single task at one post‑flight assessment, with no overall systemic cognitive decline. EEG data were analysed using cluster‑based permutation testing to compare ERP waveforms within the 0‑ to 600‑ms time window. As shown in the upper part of Fig. 1, the ERP waveforms for both participants at all three time points were nearly overlapping, with no obvious changes in the latencies and amplitudes of N100, P300, and N400. The radar plots in the lower part of Fig. 1 compare the brain vital signs metrics with reference group norms, indicating that the astronauts' metrics remained consistently within the normal range. Time‑frequency analysis using Morlet wavelets likewise revealed no significant clusters of difference. These findings suggest that after a 17‑day short‑duration spaceflight, auditory sensory processing (assessed by N100), attentional allocation (P300), and semantic integration (N400) were not significantly impaired, contrasting with the persistent changes in visual ERPs observed after long‑duration missions, and likely reflecting that short‑duration missions induce more subtle and more rapidly resolving functional brain changes.
Table 1. Participant accuracies and errors on tasks in the Cogstate battery. Scores are arcsin square root transformed such that 100% accuracy would be 1.571 and 0% accuracy would be 0.Arrow deltas indicate raw score changes,with up arrows indicating performance improvements (i.e., increased accuracy or reduced errors),and down arrows indicating performance detriments. P1 and P2 refer to participant 1 and participant 2, respectively.
Fig. 1. ERP waveforms and radar plot for participant 1 (P1) (A) and participant 2 (P2) (B) at all 3 time points (preflight = 43 and 35 d, postflight 1 = 7 and 11 d, postflight 2 = 154 and 177 d). Tone and word pair averaged ERP responses at all 3 time points. N100, P300, and N400 peaks labeled with latency and amplitude values. Radar plot for brain vital sign measures (N100, P300, and N400 amplitude and latency) at all 3 time points along with the 5% to 95% interquartile range of a reference group (aged 8 to 83 years).
Finally, this study validates the feasibility of the brain vital signs framework for rapid, repeatable assessment of individual brain function in extreme operational environments. Unlike previous reports indicating that cognitive function requires a prolonged recovery period after 6‑month missions, the two astronauts in this study exhibited cognitive and neurophysiological status at approximately 10 days after landing that showed no significant differences from baseline, suggesting that a 17‑day short‑duration flight combined with sufficient Earth adaptation time does not result in notable functional decline. The portability and automated nature of this framework confer potential for in‑orbit monitoring, enabling future EEG acquisition during spaceflight to track neurofunctional changes in real time. However, given the limited sample size (only two astronauts), the short mission duration, and the lack of in‑flight data, the conclusions should be generalized with caution. Future research should expand the sample size, include controls with varying mission durations, and refine time‑point designs (e.g., in‑flight data collection, same‑day baselines) to more comprehensively characterize individual variability and the effects of mission type on brain function. Overall, this study provides an important methodological foundation and preliminary evidence for future in‑orbit assessment of astronaut brain health in deep‑space exploration missions.