“The Dynamics of Neurobehavioural Recovery following Sleep Loss”, 2007-02-19 (; backlinks; similar):
Rate of recovery of daytime performance and sleepiness following moderate and severe sleep deprivation (SD) was examined when recovery opportunity was either augmented or restricted.
30 healthy non-smokers, aged 18–33 years, participated in one of 3 conditions: moderate SD with augmented (9-h) recovery opportunities, moderate SD with restricted (6-h) recovery opportunities, or severe SD with augmented recovery opportunities. Each participant attended the laboratory for 8–9 consecutive nights: an adaptation and baseline night (23:00–08:00 hours), one or 2 night(s) of wakefulness, and 5 consecutive recovery sleep opportunities (23:00–08:00 hours or 02:00–08:00 hours). On each experimental day, psychomotor vigilance performance (PVT) and subjective sleepiness (SSS) were assessed at 2-hourly intervals, and MSLTs were performed at 10:00h. PSG data was collected for each sleep period.
For all groups, PVT performance statistically-significantly deteriorated during the period of wakefulness, and sleepiness statistically-significantly increased. Statistically-significant differences were observed between the groups during the recovery phase. Following moderate SD, response speed, lapses and SSS returned to baseline after one 9-h sleep opportunity, while sleep latencies required 2 9-h opportunities. When the recovery opportunity was restricted to 6 hours, neither PVT performance nor sleepiness recovered, but stabilized at below-baseline levels. Following severe SD, sleepiness recovered after one (SSS) or 2 (physiological) 9-h sleep opportunities, however PVT performance remained statistically-significantly below baseline for the entire recovery period.
These results suggest that the mechanisms underlying the recovery process may be more complicated than previously thought, and that we may have underestimated the impact of sleep loss and/or the restorative value of subsequent sleep.
[Keywords: neurobehavioural recovery, performance, recovery opportunity, sleep deprivation, sleep restriction, sleepiness]