The effect of extended sleep deprivation on sleep homeostasis and cognitive performance

The effect of 58 hours of sleep deprivation on cognitive performance and physiological measures was investigated in the present study. It was hypothesized that performance deteriorates with progressive sleep loss. In addition, weak correlations were expected between subjective ratings of sleepiness and objective performance measures. During the recovery night, an increase in SWS was expected. 17 men (mean age 27 years, SD 5 years) participated in the experiment. Participants were kept awake for 2 nights and performed a test battery consisting of the PVT, N-Back Task, KSS, FAT, and waking EEG in 6-hour intervals. Moreover, sleep architecture of the recovery night was compared to a baseline night. Results indicate that there is a dose-response relationship between cognitive performance and time awake. Performance on the N-Back Task and PVT deteriorates as a function of prior wakefulness (PVT: intercept = 123.74 (± 15.3531), p < .0001; time awake= 5.488 (± 0.699), t (117) = 7.85, p < .0001). The study indicates that subjective measures of sleepiness (FAT; KSS) and objective performance measures (N-back; PVT) correlate weakly (r = ± .387 to .472). Moreover, sleep architecture during the recovery sleep differs from that of a normal night’s sleep. The analysis of the sleep cycles reveals that participants spent significantly more time in N3 sleep during the first (t= 2.75, p = .0097) and third (t= 3.39, p = .0038) sleep cycle of the recovery night. The findings underline the consequences of sleep loss and the importance of sleep.