The impact of 24 h of total sleep deprivation on eye gaze entropy in a manual spacecraft docking task.

Abstract

Introduction. Fatigue is a pressing problem in driving, aviation, and spaceflight and represents a root cause of 15-20% of accidents in transportation operations. Gaze characteristics are important means to understand and detect the effect of fatigue on operational performance. For example, changes in visual scanning efficiency have been associated with a variety of conditions, among other fatigue. This study investigates the effect of total (23h) sleep deprivation on scanning efficiency and spatial distribution of fixations by means of gaze entropy in a spacecraft docking task (6df), during which participants had to manually control a simulated spacecraft with six degrees of freedom. Methods. A counterbalanced crossover design with a sleep deprivation condition and a control condition was used. Linear mixed models were applied to analyse the data of 61 participants between the ages of 20 and 39 years (M = 24.90, SD = 4.68) with 28 female participants. Subjective sleepiness ratings were collected before each test sessions, wherein the participants conducted a sustained attention task as well as the 6df task. During the test session, eye-tracking data was continuously recorded. Results. An interaction between sleep deprivation and gender of the participants significantly affected both entropy measures. Female participants showed a significant decrease in gaze transition entropy (F(1, 54.6) = 7.84, p < .01, f2m = .03) as well as stationary gaze entropy (F(1, 55.5) = 5.08, p < .05, f2m = .03) during sleep deprivation compared to male participants, suggesting a less complex scanning pattern paired with a more deliberate and narrow examination of the visual scene. Conclusions. We conclude that visual information seeking and capturing is altered in sleep deprived female participants. This finding indicates a decreased top-down modulation of gaze control, which concurs with observed gender differences in regional homogeneity in the frontal lobe during sleep deprivation, regions of which have been associated with top-down attention. Entropy-based assessment of visual scanning efficiency allows for the study of the effects of sleep loss on operator performance throughout a variety of domains as well as practical applications in operator safety.