Is an acupuncture point identifiable with skin electrical resistance measurement?

INTRODUCTION One of the basic beliefs of traditional acupuncture is that needling and massaging on certain skin areas called acupuncture points (AP) help to treat medical conditions. While acupuncture is widely accepted as a useful non-pharmacological method for pain reduction, the mechanism of acupuncture is still debated— whether it works through the mechanical stimulation of skin and muscle nociceptors or through anatomically invisible APs and meridians. Some researchers have found that the electrical resistance of the skin over an AP is lower than that over a non-AP, and proposed the finding as indirect evidence of the existence of APs. However, the precision of skin electrical resistance measurement can be influenced by numerous factors such as dryness of skin, skin thickness, size of the sensing electrode, pressure applied on the electrode, interelectrode distance, room temperature and humidity. Most of the previous studies on AP identification were done with the sensing electrode being stabilised by hand; however, it is likely that small motions of the hand-held electrode could alter the reading of skin resistance and even bias the measurement. In the present investigation, the AP LI4 and an adjacent skin site were selected for skin resistance measurements. The measurements were conducted under stringent control in a laboratory setting. The collected data were analysed for the potential difference in the electrical resistance between the AP and non-AP.