Psychological tension estimation during the use of a driving simulator: a finger and ear pulse volume study

Finger pulse volume (FPV) and ear pulse volume (EPV) were measured to extract subjects' tension responses during the use of a car driving simulator. The results were: (1) FPV amplitude decreased in the dangerous situations of the driving simulation, (2) heart rates, which are calculated from the EPV, often increased in accordance with the decrease of the FPV amplitude. The first result shows that the user's psychological tension can be online estimated from FPV amplitudes. The second indicates that EPV can be a substitute for noisy FPV caused by artifacts. The first also suggests that changing adaptively the driving situation an the basis of FPV amplitude can maintain a user's tension.