Caffeine Selectively Reduces Cognitive Impairment Caused by Sleep Deprivation
Sleep deprivation impairs a variety of cognitive processes, but the exact mechanisms underlying these deficits are unknown.
Stepan ME, Altmann EM, Fenn KM. Caffeine selectively mitigates cognitive deficits caused by sleep deprivation. J Exp Psychol Learn Mem Cogn. 2021 May 20. Epub ahead of print. PMID: 34014758. doi: 10.1037/xlm0001023.
Commentary
It is generally known that sleep deprivation impairs attention. This study was investigating the effects of caffeine on visual attention and cognitive control processes that play a role in placekeeping, procedural performance, problem solving, and other higher-order tasks. Participants (N= 276) completed a placekeeping task (UNRAVEL) and an attentional vigilance task (Psychomotor Vigilance Task [PVT]) in the evening and were randomly assigned to one of two groups: awake overnight in the lab or asleep at home, followed by a morning Participants who slept returned to the lab, and all participants were given either 200 mg of caffeine or a placebo. All participants again completed UNRAVEL and PVT, and although sleep deprivation reduced performance on both tasks, they were able to complete the previous tasks.
As a result, caffeine appeared to counteract the deficits caused by inattention, but had no significant effect on placekeeping for most participants, although it did reduce the number of sleep-deprived participants who were unable to maintain criterion accuracy. These results suggest that sleep deprivation "directly impairs placekeeping via a causal pathway that does not include visual attention," suggesting that caffeine has limited potential to reduce procedural error rates in occupational settings.
In summary, caffeine may prevent impairments such as inefficiency due to sleep deprivation, but it does not prevent complex tasks such as placekeeping, which involves multiple steps to complete a task, even if work is interrupted in the middle of a procedural progress check.
