Abstract
A non-invasive and ambulatory technique has been devised for the quantitative evaluation of physiological and psychological stresses. The change in diameters of peripheral blood vessels is measured as the change in transmitted intensity of infrared light across an ear auricle. This signal is transmitted to a remote place using another infrared light diffusely reflected from a ceiling and walls of a room. The measurement system to realize this technique has been developed. The sensing part of this system is small and light enough to be equipped on a small experimental animal. The feasibility of this technique was verified in the measurement with a rabbit. Various types of stresses were applied and the responses in peripheral circulation were obtained. The measurement system was modified to be applied to a human subject. The R-R interval of ECG can be measured simultaneously with the peripheral circulation. The agreement between the measured results shows the usefulness of this technique.
