Effects of acute simulated microgravity on nocturnal sleep, daytime vigilance, and psychomotor performance: comparison of horizontal and 6 degrees head-down bed rest.
This study examined the effect of acute simulated microgravity on nocturnal sleep, daytime vigilance, and psychomotor performance. Each of 7 volunteers were maintained for 3 days of head-down and horizontal bed rest in a counter-balanced design. Assessment measures were polysomnographic recordings on the first night and performance on psychophysiological tasks on the second day involving subjective and objective vigilance, P300, simple reaction time tasks, and dual performance tasks. No clear difference in sleep structure was observed between the head-down and horizontal conditions, except for a slight decrease in Stage 4 for head-down. Both subjective and objective daytime vigilance, P300, and the simple RT task showed no statistical difference, although tracking performance on the dual task showed deterioration at 10:00 for the head-down condition. These results suggest that nocturnal sleep, daytime vigilance, and psychophysiological functions were not disturbed in head-down sleep conditions, although there was a mild deterioration of higher attentional function in the morning.
Komada
Yoko
Y
Japan Somnology Center, Neuropsychiatric Research Institute, Geriatric Mental Health, National Institute of Mental Health, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan. yoko@ncnp-k.go.jp
Inoue
Yuichi
Y
Mizuno
Koh
K
Tanaka
Hideki
H
Mishima
Kazuo
K
Sato
Hidetomo
H
Shirakawa
Shuichiro
S
D000328:Adult; D001288:Attention / Q000502:physiology; D001510:Bed Rest; D002540:Cerebral Cortex / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology; D018913:Event-Related Potentials, P300 / Q000502:physiology; D005583:Fourier Analysis; D018475:Head-Down Tilt / Q000502:physiology*; D006801:Humans; D007699:Kinesthesis / Q000502:physiology; D008297:Male; D017286:Polysomnography; D011187:Posture / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012815:Signal Processing, Computer-Assisted; D012894:Sleep Stages / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology*; D018474:Weightlessness Simulation / Q000523:psychology*