Electrical potential of acupuncture points: use of a noncontact scanning Kelvin probe.

Objective. Acupuncture points are reportedly distinguishable by their electrical properties. However, confounders arising from skin-to-electrode contact used in traditional electrodermal methods have contributed to controversies over this claim. The Scanning Kelvin Probe is a state-of-the-art device that measures electrical potential without actually touching the skin and is thus capable of overcoming these confounding effects. In this study, we evaluated the electrical potential profiles of acupoints LI-4 and PC-6 and their adjacent controls. We hypothesize that acupuncture point sites are associated with increased variability in potential compared to adjacent control sites. Methods. Twelve healthy individuals were recruited for this study. Acupuncture points LI-4 and PC-6 and their adjacent controls were assessed. A 2 mm probe tip was placed over the predetermined skin site and adjusted to a tip-to-sample distance of 1.0 mm under tip oscillation settings of 62.4 Hz frequency. A 6 × 6 surface potential scan spanning a 1.0 cm × 1.0 cm area was obtained. Results. At both the PC-6 and LI-4 sites, no significant differences in mean potential were observed compared to their respective controls (Wilcoxon rank-sum test, P = 0.73 and 0.79, resp.). However, the LI-4 site was associated with significant increase in variability compared to its control as denoted by standard deviation and range (P = 0.002 and 0.0005, resp.). At the PC-6 site, no statistical differences in variability were observed. Conclusion. Acupuncture points may be associated with increased variability in electrical potential.