Evaluation of driver stress using biomarker in motor-vehicle driving simulator

Employing the analysis of a biomarker, an oculomotor angle and a subjective evaluation, we have examined the acute, psychological effect human stress of driving using a motor-vehicle driving simulator. Salivary amylase is used as a biomarker, as it is considered to be one of the indicators of sympathetic nervous activity. 20 healthy female subjects in their early twenties were enrolled in this study. The time-course change of their salivary amylase activity (sAMY) is analyzed before and during the driving. At the same time, using a questionnaire, subjective evaluations are conducted with each subject. As for comparison, the effect of operating a car navigation device, which is not directly associated with driving, is also evaluated. Our results indicate that the psychological effect of driving-induced stress, a condition that can not be easily detected or recognized by a subjective evaluation, is quickly quantified using a biomarker in saliva. Moreover, the results suggest that operation of a non-driving-related device may also reduce the capacity to concentrate on driving. These data imply that evaluation of driver stress using a biomarker can be very useful for improvement of safety during driving.