Twenty-Four Hour Structure of Vigilance under Prolonged Sleep Deprivation: Relationship with Performance

摘要

The present study investigated the 36h structure of sleepiness and its relationship with psychomotor performance after 28h of sleep deprivation. Eight subjects, aged 19 to 25 years, participated after spending two adaptation nights in the sleep lab at 2300 and remained deprived of sleep until 1100. At 1100 a schedule of either 7 min sleep attemp in bed, 13 min awake outside the bedroom, or 7 min resisting sleep in bed, 13 min awake outside the bedroom, was begun and maintained for 36h until 23h on the next day. The order of the two experimental conditions, which were separated by two weeks, was counterbalanced. Polyhypnographic recordings were carried out during the 7-min in bed periods, and psychomotor testing (one and two-handed reaction time tasks) was conducted in the middle of the 13-min wake periods. Significant circadian effects were found for the two components of the psychomotor performance: reaction time and movement time. In spite of the great similarity between the circadian variations in sleepiness and the circadian variations in performance, correlating these two variables for 12h blocks revealed random and nonsignificant correlations. This negated a causal relationship between the amount of sleepiness and performance, ad suggests that both are modulated by a common underlying circadian oscillator. Keywords: Sleepability; Wakeability; Ultradian rhythms; Circadium rhythms; Reaction time task; Sleep gate.