A new device for evaluating autonomic nervous activity of cardiovascular system

The purposes of present study are to evaluate a new measurement device with a piezo sensor to obtain fluctuation of finger blood pressure signal in comparison with the conventional tonometry system. We simultaneously measured continuous blood pressure by tonomery system and finger blood pressure using our device in 12 elderly subjects. Two time series of pulse interval variability (PIV) corresponded to RR interval were estimated respectively as the time between two successive upstrokes of these two devices and systolic blood pressure variability (SPV) was also estimated as the upstroke. In time domain the relative relation of PIV estimated by two systems was high, however, that of SPV was low. On the contrary, in frequency domain, we could estimate autonomic nervous activity of vasomotor activity from our new device. The developed device in our study may be a substitutable device for conventional method as limited to estimate the autonomic nervous activity of cardiovascular system.