The Effect of Real and Sham Acupuncture on Thermal Sensation and Thermal Pain Thresholds

Abstract

Downs NM, Kirk K, MacSween A. The effect of real and sham acupuncture on thermal sensation and thermal pain thresholds. Arch Phys Med Rehabil 2005;86:1252–7. Objective To compare the effect of real and sham acupuncture and a control intervention on thermal sensation and thermal pain thresholds. Design Single-blind, randomized controlled, repeated-measures trial. Setting Laboratory. Participants Eighteen acupuncture naive, healthy subjects with no history of upper-limb pathology or acupuncture contraindications. Intervention Subjects were randomly assigned (blind card allocation) to 1 of 6 possible orders of application of the interventions, which consisted of 25 minutes each of control, real, and sham acupuncture. Main Outcome Measures Thermal sensation and thermal pain thresholds measured with a thermal sensory analyzer before and after each intervention. Results There were increases in cold and hot pain and cold sensation thresholds with real acupuncture. The level of increase did not differ significantly from the changes that occurred with sham acupuncture and control interventions. Conclusions Although we observed a trend toward a decreased sensitivity to thermal pain and thermal sensation with real acupuncture, this trend did not differ significantly from the changes with control or sham interventions. Therefore, no support was provided for analgesic or placebo effects of acupuncture. The trend, combined with the relatively low power of the inferential tests applied does, however, suggest that further research is merited.