ON-DEMAND DRIVER VIGILANCE ENHANCEMENT WITHOUT EXPLICIT DROWSINESS DETECTION - INSIGHTS FROM A PILOT STUDY

摘要

Objectives: At FISITA 2012 we proposed a new concept for active driver safety, which engages human body's endogenous pain-processing mechanism to automatically trigger vigilance enhancement on-demand. In this paper we present preliminary results from a pilot study designed to test the hypothesis that, as one becomes drowsy, his/her pain threshold will decline, thus acting as an automatic trigger for the vigilance enhancer. Methodology: We recruited six healthy male subjects to test their pain threshold movements over a time period when their vigilance would be under stress. By employing a custom steering wheel with an array of Peltier elements providing a time series of thermal stimulation through a subject's palm, we collected subject's pain-response while monitoring changes in his vigilance to establish the hypothesized correlation between vigilance change and pain sensation response in a subject. The subject vigilance state was monitored using pre- and post-session psychomotor vigilance test (PVT), in-session PERCLOS (camera on eyes, objectively), and the Karolinska Sleep Scale (KSS, subjective rating). Results: Our measure of pain threshold movements over time, as indexed by declining vigilance at various time scales, in terms of the number of painful events recorded, reveals a complex pain threshold control mechanism at work inside our body. The findings suggest that on top of a stable, constant pain threshold control that is in effect when a person is vigilant, moderately sleepy, or totally asleep, there is a secondary mechanism that engages only when one becomes extremely drowsy while wanting to stay awake, in which his/her pain threshold would move down transiently to trigger noxious-like responses as if hyper-sensitively, when in fact the presenting stimulus is still innocuous, perhaps in a last resort attempt to stifle an unwanted entry into a state of the body and the mind.