Cumulative mild partial sleep deprivation negatively impacts working memory capacity but not sustained attention, response inhibition, or decision making: a randomized controlled trial.

BACKGROUND: Twenty-eight per cent (28%) of adults sleep at least 1 hour less than they consider optimal, yet the effects of such cumulative mild partial sleep deprivation on cognitive functions are unknown. The objective of this study was to examine how cumulative mild partial sleep deprivation over 6 nights can impact working memory, sustained attention, response inhibition, and decision making.

METHODS: A double-blind placebo-controlled randomized study was conducted to determine the impact of sleep restriction (elimination of 1 hour of sleep relative to the baseline habitual sleep duration) vs placebo (exposure to a lamp with no known therapeutic effect) on cognitive performance. The primary outcomes were performance on tasks that measure working memory, sustained attention, response inhibition, and decision making. The participants consisted of 93 adults (mean age 24.3 years, SD 4.7; 46 men, 47 women) with no reported sleep problem, behavioral issue, or medical issue.

RESULTS: Performance on the working memory capacity task improved between the baseline and experimental sessions for the placebo group but not the sleep-restriction group. Performance on tasks measuring sustained attention, response inhibition, and decision making did not change under either experimental condition.

CONCLUSION: Cumulative partial sleep deprivation negatively affects performance on a test of working memory capacity but does not affect performance on tests of sustained attention, response inhibition, or decision making.