Detection Technique And Preliminary Exper-imental Study On Impedance Of Human Acupuncture Points

The theory of meridians is an important part of the basic theory of traditional Chinese medicine. For recent 10 years, the research about property of the impedance of meridians has achieved preliminary results. However, the following problems still exist: there are a great many influential factors and technical issues about the electrical property of meridians; the impedance of meridians can not reflect the changes of deep tissue; the research about meridian impedance spectroscopy and dynamic properties of meridians are scarce.Using the bio-electrical impedance technology, this article did the following jobs in two aspects based on meridians after the analysis of current situation at home and abroad. Fist, a meridian impedance detection system with high accuracy and high performance was designed, in addition, some detecting methods were presented and used. Second, the median impedance spectroscopy and dynamic properties experiments were conducted based on the system. Concretely speaking, the following aspects are included:1. A meridian impedance measuring system with high accuracy, high performance, multiple frequencies and multiple channels was designed based on the four electrode method, which cosist of the following features:1) The four electrode method was adopted in the system which effectively overcome the influences brought by interface impedance between electrode and skin and impedance of stratum corneum, also, it increased the accuracy of system and the sensitivity of changes in deep tissue of meridians.2) Equipped with multi-frequency stimulation source and digital demodulation technology, which could demodulate the complete information from impedance of meridians and adjusted by multi-point calibrated method based on two dimensional point array, the system's accuracy was greatly promoted.3) The frequency of stimulation current can be adjusted fast and accurately from 10Hz to 1MHz, and the mixed frequency in the form of sweep is also available in the system.4) The acupuncture points can be exactly located in the system: this article proposed an accurate acupuncture points positioning method. Firstly, an integrate electrode array on a flexible circuit board was made. Secondly, the location of acupuncture points is decided by the characteristic of lower electrical impedance which acquired from the multiple channels.2. By using the impedance detecting system, preliminary experiments about meridians were done, especially, the meridian impedance spectra and dynamic property experiments.1) The meridian impedance spectroscopy experimentsThe frequencies of the alternating constant current source in the logarithm equivalently distributed mode, and the characteristic parameters of impedance spectra was extracted by iterative least squares method. The results showed that the impedance for acupuncture points and adjacent points are similar in complex plane,but the distribution is different. In addition, the characteristic parameters R₀ and R_∞are sensitive to the variation of meridian impedance.2) The meridian impedance dynamic property experimentsThe measurements for dynamic features of meridian impedance were taken on healthy people in 150 minutes. The results indicated that the impedance decrease slowly as time goes by while the rate of increasing becomes slow.The results of this article pave the way for further study on relationship between meridian's electrical impedance property and diseases, and eventually, the disease diagnosis.