A method for evaluating the effect of acupuncture using multiple biosignals

A phenomenon called 'Deh-chi' is described as a kind of soreness, numbness or heavy swelling in deep tissues during acupuncture. Deh-chi and the right point of acupuncture are essential for the analgesic and therapeutical effects of acupuncture. In this study, we measured multiple biosignals (electroencephalogram: EEG), finger photo plethysmogram, respiration, skin temperature and skin impedance) when the needle was inserted into the acupoint called 'Hegu, LI₄' to examine how the physiological and psychological condition changed during acupuncture. As a result, it was confirmed that the physiological and psychological state of the subjects became more relaxed for some minutes after the beginning of acupuncture, when the needle was at the right acupoint and there was Deh-chi. Deh-chi was reflected as a remarkable variation in EEG and skin impedance. These results suggested the possibility of establishing an objective evaluation method of the therapeutical effect of acupuncture by quantifying the changes in EEG and skin impedance.