Discrimination of real and sham acupuncture needles using the park sham device: a preliminary study.

UNLABELLED Tan C-W, Christie L, St-Georges V, Telford N. Discrimination of real and sham acupuncture needles using the Park sham device: a preliminary study. OBJECTIVE To evaluate the blinding effectiveness of the Park sham acupuncture device using participants' ability to discriminate between the real and sham acupuncture needles. DESIGN The design was a yes-no experiment. Judgments were made on whether the real or sham acupuncture needle was administered. SETTING University laboratory. PARTICIPANTS Healthy, acupuncture-naive university students and staff (N=20; median age, 22y; range, 18-48y) recruited through convenience sampling. INTERVENTIONS Participants made yes-no judgments on whether the real or sham needle was administered to 8 acupoints (4 traditional and 4 nontraditional) along the Pericardium meridian (Pericardium 3 to Pericardium 6) on the dominant forearm. MAIN OUTCOME MEASURES The accuracy index, d', of participants' ability to discriminate between the real and sham needles (discriminability) was computed for the traditional alone, the nontraditional alone, and a combination of both types of acupoints. RESULTS The participants' d' between the real and sham needles was not statistically significant from d' equal to 0 for the combined traditional and nontraditional acupoints comparison and the nontraditional acupoints alone comparison (combined, t(19)=1.20, P=.25; nontraditional, t(19)=.16, P=.87). However, the participants' d' was statistically significant from d' equal to 0 for the traditional acupoints comparison (t(19)=2.096, P=.049). CONCLUSIONS The Park sham acupuncture device appears to be effective in blinding participants to real acupuncture intervention when it is applied to the nontraditional acupoints and when traditional and nontraditional acupoints are combined on the forearm along the pericardium meridian. However, the sham device does not appear to blind participants effectively when traditional acupoints alone are used for the same context.