Study of adaptive assisting effect of pre-informative, auditory-visual alert for elderly drivers using near-infrared spectroscopy (NIRS)

A major cause of traffic accidents has been found in the human factors involved in driver´s awareness during driving, and the effect of alarm was reported as the increase of awareness and the improving effect for property of perception, cognition and judgment. The arousal stimulus for driver by auditory-visual alert also affects to the physiological condition and autonomic nervous system (ANS). Recent developments in multi near-infrared spectroscopy (MNIRS) have enabled the arousal level apparent with brain activity with measurement of hemoglobin concentrations as cerebral blood volume. In this study, the three kinds of auditory alert as pre-information, sound alert and voice guidance were used and the subjective evaluation on these alerts were examined. Then the influence of auditory alert on the subject´s psychosomatic state was examined. First, after being seated the test subjects closed their eyes and encouraged to fall asleep. A 30-minutes study was conducted with the subjects in a relaxed position as they were partially awakened by auditory alert, repeatedly and measured using hemoglobin concentrations by NIRS. Next, the influence of auditory-visual alert on the driver´s psychosomatic state was examined using driving simulator for 30 minutes with 5 trials in every 5-minute interval. As the results, the effect of arousal and awareness improvement was recognized in the subjects and the activation of cerebral blood volume was observed according to the amount of the stimulus and combination of awareness modal as auditory alert system.