Investigation of the Phenomenon of Propagated Sensation along the Channels in the Upper Limb Following Administration of Acupuncture and Mock Laser

Background: Similar to De Qi psychophysical responses, propagated sensation along the channels (PSC) is considered an important phenomenon in traditional Chinese acupuncture. In acupuncture clinical trials, different acupuncture manipulation techniques are used to enhance the propagation of sensation along the channels to facilitate an optimum therapeutic result. Aim: To examine and compare the PSC reported by participants in a clinical trial following the administration of acupuncture and inactive mock laser. Methods: The study was embedded in a two-arm parallel design multicenter, randomized clinical trial, the Tennis Elbow Acupuncture—International Study—China, Hong Kong, Australia, Italy (TEA IS CHAI). Needle sensations were measured using a validated instrument, the Massachusetts General Hospital Acupuncture Sensation Spreading Scale. Ninety-six participants with lateral elbow pain were randomly allocated into two groups in a 1:1 ratio; the acupuncture treatment group (n = 47) and the mock laser control group (n = 49). Participants in both groups received the intervention at two acupoints, LI10 and LI11, consisting of 2 minutes of either standardized needle manipulation or mock laser at each acupoint with a rest period between each intervention period. Data were collected immediately following the interventions at the first and the ninth session within the clinical trial. Results: Although participants in both groups perceived PSC radiating to similar sites along the upper limb, the frequency of the reported radiation sites among the two intervention groups for both radiation up the limb (p < 0.05) and radiation down the limb (p < 0.001) were statistically significantly different. Among the radiating sensation sites recorded within the two study groups, the sensations were reported as radiating a greater distance down the forearm to the wrist compared to up the arm. Evaluation of PSC across the four study sites revealed a statistically significant difference in frequency of the reported radiation down the limb sites in each study group and radiation up the limb sites only in control group only (p < 0.001). Conclusion: The findings of the study demonstrated that the PSC phenomenon is not just associated with needling but can be perceived when using a mock laser. Trial registration: Australian and New Zealand Clinical Trial Registry reference: ACTRN12613001138774 on 11th of October 2013