Biomedical engineering meets acupuncture - development of a miniaturized 48-channel skin impedance measurement system for needle and laser acupuncture

BACKGROUND Due to controversially discussed results in scientific literature concerning changes of electrical skin impedance before and during acupuncture a new measurement system has been developed. METHODS The prototype measures and analyzes the electrical skin impedance computer-based and simultaneously in 48 channels within a 2.5×3.5 cm matrix. Preliminary measurements in one person were performed using metal needle and violet laser (405 nm) acupuncture at the acupoint Kongzui (LU6). The new system is an improvement on devices previously developed by other researchers for this purpose. RESULTS Skin impedance in the immediate surroundings of the acupoint was lowered reproducibly following needle stimulation and also violet laser stimulation. CONCLUSIONS A new instrumentation for skin impedance measurements is presented. The following hypotheses suggested by our results will have to be tested in further studies: Needle acupuncture causes significant, specific local changes of electrical skin impedance parameters. Optical stimulation (violet laser) at an acupoint causes direct electrical biosignal changes.