Preliminary Evidence of the Cognitive Cost of Insomnia: Understanding Adaptive Decision-Making during Sleep Deprivation

ABSTRACT Study Objectives The aim of this laboratory-based study was to understand the effect of total sleep deprivation (TSD) on decision-making using a reversal learning task with unannounced contingency reversals in those with chronic insomnia compared to healthy sleepers. Methods 28 individuals completed the study, 15 with chronic insomnia (7 underwent TSD) and 13 healthy sleepers (7 underwent TSD). Participants were in the laboratory for 5 days/4 nights. Following baseline sleep, participants underwent 38h of TSD or another nighttime sleep opportunity, followed by a recovery sleep opportunity for all participants. Mixed-effects ANOVAs with fixed effects of condition (healthy TSD, insomnia TSD, healthy control, or insomnia control), session (baseline or TSD/control), phase (pre or post-reversal), block (1-4), and their interactions were run to assess performance. Results There were significant effects of day, condition, phase, and their interaction (all p<0.01). Participants performed better when rested and pre-reversal (i.e., before the rule change). While both TSD groups showed poorer performance post-reversal (i.e., after the rule change) during TSD, the TSD insomnia group showed relatively intact performance pre-reversal. Conclusions TSD led to significant overall impairment on a reversal learning decision task for healthy sleepers and those with insomnia. However, the nature of impairment differed between groups. Hyperarousal may have conferred a protective effect on those with insomnia, resulting in preserved decision-making pre-reversal. These findings have important implications for our understanding of the nature of cognitive impairment associated with chronic insomnia.