Previous studies on acupuncture have focused on the ancient art’s therapeutic effects, but now – for the first time – there is scientific evidence of the response of body tissue to acupuncture needling. Conducted at the University of Vermont College of Medicine, the two-year study takes a major step towards establishing credibility among Western medical practitioners for the therapy long considered “alternative.” A report on the study, titled “Biomechanical response to acupuncture needling in humans,” will be featured in the December issue of the Journal of Applied Physiology.
Much of the skepticism about acupuncture stems from the fact that the insertion of hypodermic needles is routine in Western medicine, and is not itself considered to be therapeutic. The key to acupuncture’s biomechanical effect, says lead investigator Helene Langevin, M.D., assistant professor of neurology and a licensed acupuncturist, is not the insertion of each ultra-fine acupuncture needle, but its manipulation. No previous research has looked at the effect of the manipulation of the acupuncture needle on the tissue.
During an acupuncture session, each acupuncture needle is manipulated in order to elicit the “de qi” (pronounced “day-chee”) response. De qi is traditionally believed to be essential in achieving acupuncture’s therapeutic effect. A phenomenon called “needle grasp” is a component of de qi that is often described by acupuncturists as feeling like a fish tugging on a fishing line. When de qi occurs, patients typically experience an aching sensation.
To establish a scientific basis for acupuncture’s effect, the Vermont researchers sought to measure the force required to overcome the tissue-needle connection that occurs during needle grasp. Using a unique computer-controlled acupuncture-needling device, Langevin and her colleagues found that a much greater pullout force – 167 percent – was required when the needle was rotated in one direction after insertion than when it was not rotated. When the needle was rotated back and forth, the pullout force was 53 percent greater. This clinical study – which had a total of 60 participants – was the first to measure this effect using an objective methodology.
“We now know that needle manipulation has a measurable biomechanical effect on the tissue,” Langevin said. “This effect was present at the control and acupuncture points that we measured, but somewhat more at the acupuncture points.” Though previously believed to be a muscle contraction, Langevin’s research indicates that layers superficial to the muscle – skin and/or subcutaneous connective tissues – may be involved in the body’s response to acupuncture needling. When the needle is pulled back during needle grasp, the biomechanical phenomenon is visibly recognizable as the tissue below the skin maintains its grasp on the needle, causing the skin to “tent.”
“Our working hypothesis right now is that the needle grasp is due to connective tissue winding around the needle,” said Langevin. “We also think that the needle may come into contact with more connective tissue at the acupuncture points identified in ancient texts. This may explain why the pullout force was slightly greater at those points.”
Langevin was also the lead author of a hypothesis paper on research that supplements these findings, titled “Mechanical signaling through connective tissue: a mechanism for the therapeutic effect of acupuncture,” which appeared in the October issue of The FASEB Journal. She and her colleagues plan to focus future research on trying to prove that connective tissue is indeed involved in needle grasp.
Funding for this study was provided by the National Institutes of Health’s National Center for Complementary and Alternative Medicine. In addition to Langevin, the research team included David L. Churchill, Ph.D., Gale Weld and Jason Yandow of the department of neurology; Martin H. Krag, M.D., and James R. Fox, M.S., of the department of orthopaedics and rehabilitation; Gary J. Badger, M.S., of the department of medical biostatistics; and Brian S. Garra, M.D., of the department of radiology.
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