Physiological markers of vigilance variation in a supervisory task
Authors: Nicolas Maille, Mick Salomone, Andrea Desantis, Kevin Le Goff, Jean-François Sciabica, Marie-Christine Bressolle, Bruno Berberian
Abstract: The ability to maintain an appropriate level of vigilance over long periods of time underlies success on a range of tasks. Particularly, staying alert allows to detect infrequent signals and to allocate the right level of cognitive resources to respond to expected or unexpected events. A review of literature shows that some physiological markers can assess this variation of attention in a lot of lab studies. These findings are interesting for human factors in aeronautics as it appears as a way to characterize and quantify the observation during assessment with pilots in a cockpit simulator. The objective of this present study is to integrate a set of physiological metrics in a representative cockpit and to test their robustness in a more ecological environment with the associated constraints. This paper presents the first step of this project with a series of two lab experiments where we tested physiological markers of vigilance proposed in the literature.We first explored these markers in a psychomotor vigilance task (PVT) classically used in the study of vigilance. ECG (Heart Rate Variability or HRV), oculometrics (blink frequency, Percentage of Eye Closure or Perclos, oculomotor pattern) and EEG (alpha rhythm) were collected. The results show an increase in reaction time over time, which indicates a decrease in vigilance. They also confirm the relevance of HRV, Perclos and Alpha rhythm as a metrics of change in vigilance. In contrast, blink frequency did not appear to correlate with vigilance in our task. We then applied the relevant metrics to a second task that combined an alarm detection task and a supervisory task, the objective being to observe the robustness of the device for a task closer to the operational context. Subjective reports and changes in performance appear to reflect a decline in alertness over time. Interestingly, HRV and Perclos also seem sensitive to these changes in vigilance, but not Alpha rhythm (which could be related to the presence of noise in the signal as well as to the small number of participants). The results obtained demonstrate that the combination of ECG and eye-tracking indicators is a promising solution for the investigation of pilot vigilance in a cockpit simulator.
Keywords: Cognitive State, Vigilance, physiological markers
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