Selective Sensorimotor Impairments With Mental Fatigue Associated With G-transitions During and After Spaceflight

Abstract

Decrements in sensorimotor performance due to vestibular challenges associated with spaceflight are well characterized, and these impairments pose a significant risk to astronaut safety and mission success. However, the impact of fatigue on this impairment is unknown. We hypothesized that the interaction of fatigue and vestibular impairment would lead to greater-than-additive detriments to static and dynamic balance. Thirteen subjects (9 m/4 f) completed a series of sensorimotor tests (static and dynamic tasks, with and without galvanic vestibular stimulation) before and after a fatigue-induction task. Contrary to the hypothesis, the combination of fatigue and stimulation did not lead to increased impairment in sensorimotor task performance. Subjects displayed improved performance under GVS following the fatigue-induction task during eyes-open conditions, but not during eyes-closed or cognitive dual-task conditions, suggesting that the availability of alternate sensory cues as well as an astronaut’s level of mental workload can impact adaptation to vestibular challenges associated with spaceflight.