Contact-free Infrared Thermography for Assessing Effects during Acupuncture: A Randomized, Single-blinded, Placebo-controlled Crossover Clinical Trial

Abstract

Background Although evidence of its effects is tentative, acupuncture has long been used in the treatment of multiple maladies. So far, it has not been possible to discriminate the effects of the venue from specific results of needling itself, thus physicians merely depend on patients' statements. The authors investigated the efficacy of infrared thermography in distinguishing response to true acupuncture as compared to nonacupoint cutaneous and muscular needling (sham or minimal acupuncture), as well as without manipulation. Methods Thermographic imaging was performed in 50 healthy volunteers randomly assigned to four groups: Acupuncture of Hegu (LI 4), needling of a cutaneous and a muscular point where no acupuncture point has been described yet, and without manipulation. In a crossover protocol, each proband completed all four arms of the protocol in a random order. Infrared thermograms were gathered at defined points in each group. Results A significant increase in surface temperature occurred within 2 min after needling the acupuncture point Hegu (from 30.1 +/- 2.7 degrees C [SD] to 31.2 +/- 3.0 degrees C and to 31.9 +/- 2.5 degrees C after 10 min, P < 0.001), whereas needling of the cutaneous and muscular point, as well as without any manipulation resulted in a decrease of temperature in the monitored area. Conclusion Contact-free infrared thermographic imaging is a reliable and easy-to-handle tool to distinguish between needling at Hegu and needling of a nonacupoint ("sham" acupuncture).