Analysis of sound characteristics originating from the brachial artery in auscultation

Auscultation is widely used as non-invasively sphygmomanometry in the field of medicine. Diastolic and systolic blood pressure based on Korotkoff sounds are used as an indicator of human health condition. We have hypothesized that the sounds emerging from the brachial artery in auscultation might have some other information that can be used as new indicators. These sounds contain a different frequency component based on each individual artery. Therefore, it is necessary to analyze those sounds over the frequency range to detect the characteristic factors. In this study, we constructed a system to investigate the sounds that emerge from the brachial artery in the diastole of the cuff in auscultation. In this system, a conventional condenser microphone fixed on the throbbing location of the upper right arm was used to measure the sounds and then analyze them with a personal computer. We compared the subjects in a normal condition with the subjects with hypertension. It was observed that the sound waveforms of the subjects with hypertension were different from those in a normal condition. It was hypothesized that these differences of waveform depend on health condition, age, hypodermal difference, sex and so on