Who is vulnerable to sleep loss? A cognitive dimension approach to predict cognitive impairments after experimental sleep restriction
Sleep loss is common and can lead to drastic changes in cognitive functions. However, while some individuals suffer from severe impairments, others manage sleep loss easily. There is currently a poor understanding of the mechanisms behind these different reactions, and the field suffers from mostly under-powered studies.
We want to address these problems by taking a large-scale approach, determining within-subject changes in 500 individuals after normal sleep (8h/night) and after two nights of restricted sleep (4h/night). This will allow us to determine the magnitude of cognitive impairments after sleep loss with much better accuracy than previous studies. We will also test a model where a person’s cognitive profile (in the domains of attention, emotion regulation, perceptual stability, and meta cognition) predicts cognitive impairments following restricted sleep. The big data approach will further allow data-driven analyses to find traits and mediators aiding tolerance to sleep loss.
This project, the largest sleep experiment ever conducted, will provide fundamental knowledge of how sleep loss affects several cognitive domains, and the extent to which one s cognitive profile predicts such vulnerability. This is highly relevant, considering the prevalence of disturbed sleep in today s society, and knowledge about how individuals are differently affected will be useful both on a personal level, and to prevent accidents due to cognitive failures at work and in public settings.
Final report
The main goals of the project were to determine how restricted sleep affects cognitive functions and why some individuals are vulnerable to sleep loss and others are resilient. With this aim, we have carried out a large-scale study where we, in a within-subjects design, studied subjects after both sleep saturation (two nights with 8-9 hours in bed/night) and after sleep restriction (two nights with 4-hours in bed/night). All subjects have filled out 23 background questionnaires (assessing predictors), had their sleep measured, performed 13 cognitive tasks in the sleep laboratory, and made ratings of mood symptoms and motivation. The study has followed the plan, with some additions, and we have managed to collect data from 450 individuals – which makes this the largest sleep experiment in the world so far. We are also creating a database, detailing a plan for analyses of data, and a pre-registration for 10 articles. This is a unique database, allowing analyses of individual differences in cognitive functioning both cross sectionally and after exposure to a stressor (sleep loss). Many other research groups are interested in our data, and we have started collaborations with several other research groups. Articles and analyses have to be pre-registered before access to requested data. The project will primarily publish articles on the following topics: 1) What are the effects of two nights of sleep restriction on various cognitive functions? 2) How individuals differ in their cognitive responses to sleep loss (including how many individuals can be seen as tolerant and vulnerable to sleep restriction for different cognitive functions)? 3) Which factors predict vulnerability in different cognitive functions after sleep loss? In all, the project will result in articles providing good estimates of true effects, have the power to analyse also smaller and medium-sized effects, and contribute to robust science.