Sleep and Performance Research Center

Human Sleep and Cognition Laboratory

Hans P.A. Van Dongen, Ph.D. (see CV)

AREAS OF INTEREST

Sleep Deprivation, Sleepiness, Cognitive Performance, Fatigue Modeling, Fatigue Risk Management, Sleep Physiology, Homeostatic and Circadian Mechanisms, Individual Differences

RESEARCH SCOPE

In today’s 24/7 society, there is an increasing need for people to be awake and at work at all hours of the day. Extended work hours and night and shift work compete with the biological need to sleep and with daily rhythms driven by the biological clock. Even modest amounts of sleep loss lead to increased sleepiness on the job, during the commute, and at home – jeopardizing productivity, safety, and well-being. Individual differences in these effects are substantial.

In the Human Sleep and Cognition Laboratory, we study sleep and wakefulness in normal people, going about their everyday lives or sequestered in the laboratory, to answer key questions about the effects of reduced and displaced sleep on cognitive performance. Our goal is to find out how these effects can be understood and prevented or mitigated.

RESEARCH FOCUS

Broadly, the research program of the Human Sleep and Cognition Laboratory focuses on sleep, sleep deprivation, circadian rhythms, and cognitive performance. With pillars in basic science and laboratory experimentation as well as applied research, field studies and mathematical modeling, the research program crosses multiple academic disciplines, including neuroscience, physiology, psychology, medicine, statistics, mathematics, and human factors. The research forms a well-integrated program focused specifically on the effects of sleep loss and circadian misalignment on brain function, cognition, and behavior. Recent and current research foci include:

Trait individual differences in vulnerability to sleep loss. In a line of research first started at the University of Pennsylvania, and funded by NASA and the National Institutes of Health (NIH), we were the first to demonstrate that individual differences in cognitive impairment due to sleep loss constitute a trait. There are both sleep homeostatic and circadian rhythm aspects to the trait. This line of research led to a world-wide search for the genetic underpinnings. We identified the most predictive genetic polymorphism for this trait discovered to date, TNFα G308A. We also showed that individual differences in cognitive impairment due to sleep loss are task-dependent – an important observation that gave rise to the next research focus.

Effects of sleep deprivation on component cognitive processes. In a fruitful collaboration with the Department of Psychology at Washington State University, and with funding from the NIH and the Office of Naval Research, we showed that the effects of sleep deprivation on task performance depend fundamentally on the cognitive processes involved. Through local, national, and international collaborations, we collected experimental, neuroimaging, theoretical, and mathematical evidence that these effects are based in neuronal circuits subserving the cognitive processes involved in the performance task at hand – in a local, use-dependent manner. This line of research also led to the discovery of feedback blunting, a novel mechanism explaining why sleep deprivation is particularly detrimental when making critical decisions in dynamic situations. Current laboratory studies focus on the effects of sleep deprivation on cognitive flexibility.

Fatigue risk management. Based on our laboratory research, we developed a new class of mathematical models of sleep and performance, which are at the forefront of operationally relevant tools for predicting fatigue. In field research and simulator studies, we investigated the fatiguing effects of extended work hours and night and shift work in pilots, truck drivers, and other populations whose work schedules are affected by the 24/7 economy. This recent and ongoing work is funded by both government agencies and industry partners. We are developing and validate fatigue countermeasures, and do research in the context of federal policy making.