Original paper Acupunct Med 2011;29:47–50. doi:10.1136/aim.2010.002485 47 ABSTRACT Objective The aim of this study was to test whether acupuncture could modify the threshold of tolerance to thermal and electrical stimuli. Methods A randomised placebo-controlled single-blind trial was conducted in 36 healthy volunteers randomly distributed to control (no treatment), conventional acupuncture and sham acupuncture groups. The subjects were blind to the group allocation. The authors measured before and after treatment the pain threshold with the Painmatcher (Cefar Medical AB, Lund, Sweden) and the cold tolerance with the cold pressor test, together with the Visual Analogue Scale pain score. Results Electrical stimulation threshold and cold pressor tolerance both increased significantly in the control and the true acupuncture groups, but not the sham group. The changes in the true acupuncture group were highly statistically significant and amounted to 24% (pain threshold) and 44% (cold tolerance) increases in threshold. The changes in the true group were significantly greater than the control group but not significantly different from the sham group. The changes in the sham and control groups were not significantly different from each other. Conclusion Acupuncture at true, appropriate points was more effective than no intervention in raising pain threshold and tolerance in volunteers, and acupuncture at inappropriate points had an intermediate effect which was not significantly different from either. Thus acupuncture analgesia may not be a point specific effect. INTRODUCTION Various non-invasive techniques are used to test variations in pain threshold. In this ran- domised controlled single-blind trial, a non- acupuncturist experimenter has observed whether needle insertion could modify thresh- old of tolerance to thermal and electrical stimuli. Acupuncture (or electroacupuncture) is used as a complementary or alternative treatment of acute and chronic pain. 1 Its effectiveness is sometimes questioned 2–3 or even rebutted. 4 Specific electrical, 5 histological 6–7 and physio- logical 8 properties of classical acupuncture points have been discussed and the existence of the meridians 7 remains hypothetical. 5 Recent Acupuncture effect on thermal tolerance and electrical pain threshold: a randomised controlled trial Marc Amand, Florence Nguyen-Huu, Costantino Balestra Department of Environmental & Occupational Physiology, Haute École Paul-Henri Spaak, I.S.E.K. (Institut Supérieur d’Ergothérapie et de Kinésithérapie), Brussels, Belgium Correspondence to Mr Marc Amand, Department of Environmental & Occupational Physiology, Haute École Paul-Henri Spaak, ISEK (Institut Supérieur d’Ergothérapie et de Kinésithérapie), Avenue Schaller, 1160, Brussels, Belgium; marcamand@skynet.be Accepted 27 September 2010 Published Online First 7 December 2010 studies reveal that acupuncture seems to stim- ulate immune defences, 9 generate a decrease in substance P 10 and modulate the endogenous opioid systems (enkephalins, β-endorphin and endomorphins). 11 Sham acupuncture seems to have different effects: positron emission tomography scanning suggests that classical acupuncture induces an increase in opioid receptor activity both in long and short terms, which does not occur with sham acupunc- ture. 11 Scanning with fMRI shows a reduced activity in the limbic system with classical acu- puncture stimulation. 12 The penetration of the needle leads to a significant reduction of blood flow in the ipsilateral frontal gyrus and, during the manual stimulation of the needle, changes are observed in the contralateral putamen with classical acupuncture group but not with the sham group. 13 Our study aim was to test whether acupunc- ture induces hypoalgesia as measured by the cold pressor test (CPT) and electrical stimula- tion test (EST) using the Painmatcher (Cefar Medical AB, Lund, Sweden). MATERIALS AND METHODS Thirty-six subjects (16 women and 20 men), students in physiotherapy, healthy volunteers have been recruited from the Institut Supérieur d’Ergothérapie et de Kinésithérapie in Brussels. The study was approved by the Academic Ethical Committee (CE-2009-03-23-vs1), Brussels and informed consent form was obtained from each participant. The subjects were assigned by computer software (GraphPad StatMate V.1.0) in three groups: control, test acupuncture and sham acupuncture. The sub- jects had never had acupuncture training or treatment and met the inclusion criteria, for example, no recent or former upper limb trauma, or neurological disorders. They pre- Summary points ▶ Acupuncture is used to treat pain. ▶ We tested its effect on pain threshold in volunteers. ▶ Acupuncture at true points was superior to no intervention, but not significantly different from acupuncture given at non-point locations. on 22 July 2018 by guest. Protected by copyright. http://aim.bmj.com/ Acupunct Med: first published as 10.1136/aim.2010.002485 on 7 December 2010. Downloaded from