Markers of Susceptibility to Neurobehavioral Decrements in Spaceflight
David F. Dinges, Ph.D.
Perelman School of Medicine at the University of Pennsylvania
This project is responsive to the NSBRI Neurobehavioral and Psychosocial Factors Team goal to validate objective markers of susceptibility to stress, fatigue and neurobehavioral decrements associated with long-duration spaceflight, and to the NASA HRP Behavioral Health and Performance gap to find individual characteristics that predict successful adaptation and performance in an isolated, confined and extreme environment, especially for long-duration missions.
Sleep loss is common in spaceflight, but there are currently no valid objective markers of the large inter-individual differences in susceptibility to its neurobehavioral effects. To fill this gap, the project will validate promising novel markers of susceptibility to fatigue-related neurobehavioral decrements. This will be accomplished by conducting a factor analysis of a historical database of cognitive, subjective and physiological responses to acute and chronic sleep loss in healthy adults (N=640), in order to identify core dimensions of neurobehavioral responses to sleep loss. These dimensions will then serve as targets for prospectively assessing the predictive power (separately and in combination) of each of five objective markers that include physiological (brain activity, heart rate variability, salivary amylase), behavioral (time on task performance) and genetic (common polymorphisms) measures for susceptibility to neurobehavioral responses to sleep loss. This prospective validation will be accomplished by adding the predictor markers to three separate studies on sleep deprivation that are under way during the three-year project timeline.
Across the three studies being leveraged, there are a total of N=120 healthy adults (diverse in age, gender, ethnicity) on which predictive validation will be performed. Finding valid markers of susceptibility to neurobehavioral deficits from total and chronic partial sleep loss will make it possible to optimize crew resources and fatigue management during long-duration spaceflight, and it will have substantial benefits for fatigue management in many Earth-based, safety-sensitive operations.