Pupillometric sleepiness measurements PST with concurrent video optic sensor of pupillary size

摘要

The article describes the design solutions of a mobile headset device used for the assessment of involuntary and oscillatory movements of the pupils. The pupillographic sleepiness test (PST) is used to assess the human psychophysiological state influenced by the level of drowsiness or alertness by observing the so-called fatigue wave. Since the overall size of the pupil is controlled predominantly by sympathetic inhibition of the parasympathetic Edinger-Westphal nuclei, spontaneous changes in its size are considered to be the result of decreasing central sympathetic activity. In the state of reduced alertness, changes in pupil size recorded in the dark show slow rhythmic oscillations, called fatigue waves. PST must be carried out in complete darkness (infrared goggles) and silence for a duration of 11 min. Authors used the results of studies conducted before the development of the device. Those results played a significant role in shaping the structural assumptions on the sensor in its function as an indicator of the level of human fatigue. The article includes the results of the experimental research on the sensor's testing process involving variable frequency parameters of light, luminance and chrominance excitations. The obtained results revealed that the type of light stimulating the retina has significant impact on the oscillation parameters of pupils. (C) 2015 Published by Elsevier Sp. z o.o.. on behalf of Nalecz Institute of Biocybernetics and Biomedical Engineering.