Aug 26 2011

Acupuncture and Acoustic Waves

Here is yet another study claiming to show “how acupuncture works” when in fact it does nothing of the kind. The bias of the researchers is so obvious in this study it’s astounding that it was published in a peer-reviewed journal. Of course, the mainstream media is dutifully reporting the biased claims of the researchers without any independent verification or analysis.

There are numerous fatal problems with this study. The first, like in many physiological studies that purport to be about acupuncture, is that the connection to acupuncture is tenuous. The researchers claim that they are testing the effects of an acupuncture needle – but what makes a needle an acupuncture needle? Other such studies were ultimately just seeing the effects of local tissue trauma. The fact that this trauma was induced by an “acupuncture needle” is not necessarily relevant.

This study is far worse, because it is simply using the acupuncture needle as a mechanism for inducing an unrelated physiological stimulus. This is similar to “electroacupuncture” where electrical current is applied through an acupuncture needle – what you are actually studying is the effects of electricity, not “acupuncture.”

This is the most significant fatal flaw of this study. What the researchers did was use an”acupuncture needle” (i.e. a needle) to apply a mechanical vibration (through a piezoelectrical device – one that converts electricity to mechanical force, or vice versa)  to the tissue. They justify this procedure by likening the vibration to manual manipulation that acupuncturists will do to the needle after insertion.

However – they were vibrating the needle at up to 50 hz – 50 times per second. There own data shows that lower frequencies have no physiological effect. Essentially the researchers were measuring acoustic shear waves (ASW) – in the tissue in response to this vibration. This is less than shocking – vibrational waves in tissue in response to vibration. Wow. But they also measured the release of calcium by the cells. They argue that the ASW cause the local cells to release calcium which then in turns triggers the release of endorphins – and that’s how acupuncture works.

What they actually showed, if anything, is that acupuncture does not work through this mechanism. They proved the opposite of what they claim, because their own data shows that the calcium release is present at 40hz, it is barely present at 20hz, and completely absent at 10hz and 5hz. So, to be generous, unless the acupuncturist is continuously vibrating the needle at 20 times per second, the physiological mechanism they are seeing is not relevant. It’s impossible, using just your hands, to vibrate a needle at 20hz. Further – acupuncturists don’t vibrate the needle, they may twist them or move them up and down, but not at anything approaching 20hz. The authors themselves state:

In studying acupuncture, an important and frequently overlooked procedure is the manual needle manipulation performed by acupuncturists after needle insertion. The needle manipulations are typically a series of rapid bidirectional rotation or up-and-down piston movements.

The authors failed in the most basic sense to demonstrate that their physiological model is at all relevant to acupuncture; they failed to note the relevance of the frequency of the vibrations they were using or the plausibility that this relates to the “rapid” movements of the needle that acupuncturists sometimes make.

The study also looked at the acoustic waves themselves and claim that they were more pronounced when the needle was inserted at an acupuncture point than when at a non-acupoint. I find this result frankly unbelievable. A review of the research does not support the notion that acupuncture points or meridians exist. Further, the clinical research shows that there is no difference in effect between needling acupuncture points or non-points (sham vs “true” acupuncture). About this the authors write:

Along with it is a system of tracks called meridians by the practitioners but invisible anatomically.

By “invisible anatomically” they mean – there is no evidence they exist. Meridians are the floating, invisible heatless dragons of Carl Sagan.

The fact that these researchers found results that depend on the existence of acupuncture points seriously calls into question their methods. Their results should be viewed  as the equivalent of N-rays or Bem’s future cognition results – likely artifacts of sloppy research and researcher bias.

It should also be noted that this study did not even look at clinical effects from acupuncture, so they were unable to correlate any of the physiological parameters they were looking at with any putative effect. Therefore there are good reasons for thinking the effects they are seeing are not relevant to acupuncture, and the researchers provide no evidence that they are.

The flaws outlined above are enough to render this study useless as support for acupuncture, but I think it’s also worthwhile to consider the bias of the researchers. I usually don’t spend time doing this, but there are a few points worth making with respect to this study. This study comes out of Hong Kong. There is a Columbia University author, but he is a non-MD electrical engineer who provided only technical assistance, and is not a medical researcher. This is relevant because a prior review of acupuncture research published in 1998 showed that 100% of the acupuncture studies coming out of Hong Kong (and several Asian countries) were positive. This is in stark contrast to acupuncture studies from the West or overall.

The most reasonable conclusion to draw from this is that there is extreme researcher and/or publication bias in these countries. Proponents might argue that Asian researchers know how to do acupuncture properly, but that explanation is not credible, and doesn’t apply to physiological studies like the current one.

I also note that one of the lead authors, Siu Kam Lam, was convicted of stealing 3.8 million dollars in donations while in public office and served jail time for this crime. Facts like this are always difficult to deal with. Withholding this information from this article seems like an omission, as this might be relevant in putting the honesty of the researchers into context. But it can also be interpreted as poisoning the well. In any case – I see it as full disclosure, and the reader can make of it what they will.

I will also note that the authors, in their introduction, give a glowing review of acupuncture, and shamelessly cherry pick the evidence to make it seem as if there is good published support for acupuncture. The opposite is true – systematic reviews show that there is no specific effect from acupuncture. It is nothing more than a ritualized placebo.


There is no evidence for any of the underlying claims of acupuncture – not even the existence of acupuncture points. The clinical research shows that acupuncture does not work – in order words, that it does not matter where or even if you stick the needles. Acupuncture is a placebo treatment.

Acupuncture proponents, however, continue to study the non-specific local physiological effects of sticking needles into tissue, and often even producing a physiological stimulus through the needle that has nothing to do with how acupuncture is practiced. They then claim that “finally” they have discovered how acupuncture works.

This current study is no exception. But interestingly, this study may be the first that actually proved that they found a mechanism by which acupuncture cannot work. The effect they found was only present when the needle was vibrated at 20hz or more – something which is not done and seems impossible for the acupuncturist to achieve.

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