This paper proposes a noninvasive method for estimating the dynamic characteristics of arterial walls using pulse waves measured in various parts of the body by a foil-type pressure sensor. The sensor was employed to measure pulse waves based on the tonometry approach, and a method of estimating changes in arterial viscoelastic indices was proposed based on the measured pulse waves and photoplethysmograms. In order to accurately measure blood pressure, we examined suitable mechanical forces externally applied to the sensor, and found that values of 5-25 [N] yielded the best performance. We then estimated the arterial viscoelastic indices of a radial artery and a dorsal pedis artery when mechanical pain stimuli were applied to the subjects. The results suggested the estimated indices can be used to quantitatively assess vascular response caused by sympathicotonia. We thus concluded the proposed method enabled noninvasive measurement of pulse waves and estimation of viscoelastic indices.
