An artificial heart was not controlled by any nerve system now, but sympathetic nerve activity should be used for control of the artificial heart to work more physiologically. Although it has been difficult to develop an electrode that can be used for long-term experiment of sympathetic nerve system, we developed a new carbon fiber electrode for the long-term use. It was implanted in sheep with the left ventricular assist system(LVAS)and renal sympathetic nerve activity(RSNA)was recorded. Wireless telemetry measurement system was used for recording of RSNA and it is observed that discharge of RSNA and the pulsation of self-heart occurred simultaneously. The amplitude of RSNA discharge was approximately 20μ Vp-p. Although correlation coefficient between integrated renal sympathetic nerve activity(IRSNA)and heart rate(HR)was not so high, it was shown that reaction of autonomic nerve system could be applied to artificial heart control.

View full abstract

The purpose of this paper is to develop a health emergency system for the elderly living alone against a health problem, such as a stroke.Firstly, we analyzed in-house movements of the elderly from staying period in rooms placing infrared sensors in each of their rooms.As a result, we found that their staying periods in rooms vary from one room to another. Especially, periods in lavatories, bathrooms and kitchens are shorter. Staying in those rooms longer than usual implies that there is something unusual, perhaps an emergency. Secondly, we determined threshold values based on the data of previous 30 days and we were able to detect some incidences over the threshold. Then, we found that habitual change of the way to use rooms or to go out can be detected as abnormal staying period depending on the usage of room. In addition, we found that staying period in a specific room such as a lavatory also gave us a different kind of useful information on the monitored. In conclusion, it was found that to monitor staying period in rooms can be applied to an automatic emergency call system.

View full abstract

Auscultation of the vessel sound is widely used in the field of medicine such as sphygmomanometry. Systolic and diastolic blood pressure measurement based on Korotkoff Sounds identification have been used as an indicator of biophysical condition. We hypothesized that the sounds emerging from the brachial artery contain information of the vessel wall nature and peripheral resistance. These sounds contain several frequency components those thought to have relationship to each individual arterial condition. We analyzed Korotkoff Sounds by FFT method to detect the characteristic factors.In this study, we compared Korotkoff Sounds spectrum in 10 young subjects and 17 elderly subjects to investigate the effect of age differences. In addition, to evaluate the effect of peripheral resistance changes, Korotkoff Sounds were measured in 6 young subject before and after administrating vasodilator. Results showed the differences in sound spectrum were observed as with the differences in age. It was indicated that individual arterial condition might be revealed with the frequency component of Korotkoff Sounds.

View full abstract