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Oculomotor function during space flight and susceptibility to space motion sickness.
1NASA Johnson Space Center, Houston, Texas.
Acta Astronautica
|January 1, 1991
Summary
Spaceflight alters saccadic eye movements, increasing latency and decreasing velocity. Susceptibility to space motion sickness (SMS) correlates with these changes and impaired vestibulo-ocular reflex suppression.
Area of Science:
- Neuroscience
- Space Physiology
Background:
- Space motion sickness (SMS) affects astronauts, impacting performance.
- Understanding the vestibulo-ocular reflex (VOR) and saccadic eye movements (SEM) is crucial for spaceflight adaptation.
Purpose of the Study:
- To investigate the effects of weightlessness on VOR and SEM.
- To correlate VOR and SEM changes with SMS susceptibility and occurrence.
Main Methods:
- Studied 18 subjects before and during Space Shuttle missions.
- Assessed horizontal VOR using active sinusoidal head oscillation (VVOR, VOR-ES, VOR-S).
- Recorded eye movements via electrooculography and head position via potentiometer.
Main Results:
- No significant in-flight changes in VOR gain, phase, or waveform.
- Increased saccadic latency and decreased saccadic velocity observed.
- Preflight VOR suppression differences noted between SMS-susceptible and non-susceptible individuals.
Conclusions:
- Weightlessness primarily affects SEM, not VOR, in most subjects.
- SMS susceptibility is linked to impaired VOR suppression and altered SEM during spaceflight.