Cognitive and balance functions of astronauts after spaceflight are comparable to those of individuals with bilateral vestibulopathy

Front Neurol. 2023 Oct 27:14:1284029. doi: 10.3389/fneur.2023.1284029. eCollection 2023.

Abstract

Introduction: This study compares the balance control and cognitive responses of subjects with bilateral vestibulopathy (BVP) to those of astronauts immediately after they return from long-duration spaceflight on board the International Space Station.

Methods: Twenty-eight astronauts and thirty subjects with BVP performed five tests using the same procedures: sit-to-stand, walk-and-turn, tandem walk, duration judgment, and reaction time.

Results: Compared to the astronauts' preflight responses, the BVP subjects' responses were impaired in all five tests. However, the BVP subjects' performance during the walk-and-turn and the tandem walk tests were comparable to the astronauts' performance on the day they returned from space. Moreover, the BVP subjects' time perception and reaction time were comparable to those of the astronauts during spaceflight. The BVP subjects performed the sit-to-stand test at a level that fell between the astronauts' performance on the day of landing and 1 day later.

Discussion: These results indicate that the alterations in dynamic balance control, time perception, and reaction time that astronauts experience after spaceflight are likely driven by central vestibular adaptations. Vestibular and somatosensory training in orbit and vestibular rehabilitation after spaceflight could be effective countermeasures for mitigating these post-flight performance decrements.

Keywords: astronauts; bilateral vestibular hypofunction; bilateral vestibular loss; reaction time; spaceflight; time perception; vestibular tests.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. The National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) provided access to the astronauts and the International Space Station. Centre National d'Etudes Spatiales and CADMOS provided the equipment and travel support for the investigators (grant # 2023/4800001180). Région Normandie provided financial support for data collection with the BVP subjects, data analysis, and publication (grant # 00115524-210E06581). The astronauts' data reported here were from the NASA Human Research Program Standard Measures Cross-Cutting Project.