0252 EXPERIMENTAL CUMULATIVE SLEEP RESTRICTION IMPAIRS WORKING MEMORY BUT NOT DECISION MAKING

Abstract

Introduction: Eighteen percent of young adults are sleep deprived. Sleep deprivation leads to significant neurobehavioral impairments and compromises job and academic performance and driving safety. Data is scarce and contradictory regarding the impact of cumulative sleep deprivation on neurobehavioural functoning (NBF). The objective of this study was to assess the impact of cumulative sleep restriction on the NBF of young adults. Method(s): Participants: Sixty-five healthy participants (ages 18-34). Design(s): A double-blind, placebo controlled, randomized trial. Participants were randomized into experimental and placebo conditions. Each participant completed a period of baseline protocol and an experimental period. The experimental period lasted 6 nights and had 2 conditions: 1) sleep restriction condition -participants were asked to restrict their sleep by one hour per night 2) placebo condition- participants were asked to use a lamp which had no clinical effects for 30 minutes during day time. NBF was assessed at baseline (Day 1) and following sleep manipulation (Day 12). Measures: Sleep duration was assessed using actigraphy, an accelerometer that measures sleep objectively based on movement. NBF was measured using the Cambridge Neuropsychological Test Automated Battery Spatial Span task and the Cambridge Gambling Task for working memory and decision-making, respectively. Result(s): Poorer performance on spatial span task was found in the experimental condition compared to the placebo condition, controlling for baseline spatial span length, sex, age, sleep efficiency during experimental week, baseline sleep duration, and chronotype, (F(1,49)=5.18, p < 0.05). No significant effects for sleep restriction were found on decision making measures when comparing the experimental condition to the placebo condition. Conclusion(s): Young adults' performance on spatial working memory task deteriorated following cumulative sleep deprivation whereas their performance on decision making task was not affected. The present study indicates that sleep deprivation has a differential impact on the NBF of young adults.