Hypalgesic efficacy of acupuncture on experimental pain in man. Comparison of laser acupuncture and needle acupuncture.

The analgesic effect of acupuncture on cutaneous heat stimuli of 43 degrees C has been evaluated in a controlled experimental study with healthy, informed volunteers. Laser acupuncture was administered to 39 probationers using a helium-neon laser under double-blind conditions. The point Hegu (L.I.4) and Jianqian (Extra.) on both sides were each irradiated for 1 min. Forty probationers were needled with stainless steel needles in the point Hegu (L.I.4) on both sides under single-blind conditions. Pain threshold was measured in terms of the time (in msec) that the probationers needed to perceive the cutaneous heat stimulus of 43 degrees C. The painful stimulus was generated by a computer-controlled standardized procedure. The Wilcoxon test was used for the statistical evaluation. Laser acupuncture did not change the pain threshold. Needle acupuncture did, however, increase the pain threshold compared with the initial value (alpha = 0.1%). The difference compared with the control group, where a placebo point was needled, was also significant (alpha = 5%). This controlled experimental study proves the analgesic effect of needle acupuncture on painful heat stimuli. Laser acupuncture had no effect on pain threshold in this study.