Extraction and Evaluation of Discriminative Indexes of the Wearing Condition for High-Precision Blood Pressure Pulse Wave Measurement

In this paper, we report a new discriminant index for evaluating the wearing condition of a blood pressure pulse wave measurement device with small variability. The prototype device consists of MEMS 3-axis force sensors, a 3-axis push-in adjustment mechanism, a fixed jig, and a signal processing board. The arterial tonometry method is used by this device to measure blood pressure pulse waves. However, to accurately measure the blood pressure pulse wave, the device must be appropriately worn. The evaluation of the wearing condition using the amplitude of the blood pressure pulse wave was complicated by the wearing process due to the large variability. Therefore, we propose the ratio of the blood pressure pulse wave component to the noise component as an index that can evaluate the wear condition of the device. The correlation coefficient between the discriminant index and the amplitude of the blood pressure pulse wave had a correlation coefficient of 0.879. Furthermore, the discriminant index reduced the coefficient of variation by 12.8%. Therefore, it was suggested that the discriminant index is an index that can evaluate the pressing amount, one of the wearing conditions of the blood pressure pulse wave measurement device with a small influence of variation.