An Investigation of Fatigue and Cognitive Disengagement in Insomnia

Insomnia Disorder (ID) is characterized by daytime symptoms including fatigue and complaints of cognitive impairment. However, objective cognitive testing has largely found that people with ID perform similarly to healthy sleeping controls. Some have speculated that despite maintaining their performance, those with ID perceive these tasks as more effortful, contributing to this discrepancy. Furthermore, objective cognitive testing is designed to test maximum cognitive functioning under optimal conditions, which may not generalize to the real world. Fatigue is characterized by increased perceptions of effort and decreased motivation to sustain cognitive or physical performance and can be induced by challenging tasks or long periods of time on task. Notably, how people think about their available resources influences perceptions of fatigue and task performance. The consequence of increasing fatigue is disengagement to conserve resources; this occurs physiologically and behaviorally. Thus, under non-optimal testing conditions (i.e., challenging and long), people with ID may experience more fatigue and be more likely to disengage from cognitive tasks to conserve resources, displaying objective cognitive performance more akin to their subjective reports of impairment. Study 1 used an experimental “high effort” prime to investigate how perceptions of task demands influence ratings of fatigue and cognitive resources over time. Further, it investigated whether cognitive disengagement is a potential mechanism of poor objective cognitive functioning in a sample of...