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Does Chinese acupuncture affect the brain's ability to regulate pain? PDF Print E-mail
Swift
Written by Christina Stephens   

A new acupuncture vs. placebo acupuncture study has been making headlines due to results of a study suggesting that there may be a difference in opioid receptor response in acupuncture vs. placebo acupuncture.

Several large-scale studies [1-3] have been released showing that acupuncture and various forms of placebo acupuncture have clinically insignificant differences in the reduction of pain, proponents of acupuncture are now looking at brain-imaging to explore the mechanisms of acupuncture and placebo acupuncture to determine if acupuncture and placebo acupuncture operate via different mechanisms.

In this study [4], researchers hypothesized that long term acupuncture therapy may result in increased opioid receptor availability and that these effects would not be observed in a placebo acupuncture group. Their subjects consisted of 20 women randomly divided into 2 groups of 10 subjects. One group received traditional acupuncture treatment while another group received non-invasive, placebo acupuncture. Results from PET scans using contrast material were taken during a 90-minute period, during which acupuncture treatment or sham acupuncture treatment was administered during the 45-90 minute timeframe. A period followed in which subjects received 7 acupuncture or sham acupuncture treatments, and then the PET scan procedure was repeated, for a total of 9 treatments. Results indicate acupuncture therapy evoked short-term increases in MOR binding potential, in multiple pain and sensory processing regions including the cingulate (dorsal and subgenual), insula, caudate, thalamus, and amygdala. Acupuncture therapy also evoked long-term increases in MOR binding potential in some of the same structures including the cingulate (dorsal and perigenual), caudate, and amygdala. These short- and long-term effects were absent in the sham group where small reductions were observed, an effect more consistent with previous placebo PET studies.

There are several pieces of information regarding this study that were left out of news headlines an abstracts, so I will attempt to summarize them here and then offer my own analysis of the results. However, it should be clear that I am not a neurologist, and thus my knowledge of neurology is somewhat limited.

Subjects were blinded to which treatment group they were in, and they were also asked to guess which treatment group they thought they were assigned to after the first PET scan. There was no significant difference between groups, and thus it can be assumed that the subjects remained adequately blinded, though the study does not mention any blinding of the researchers, making it quite likely that the researchers were unblinded, which could have an effect on the study results.

During the acupuncture treatment, needles were left in during PET scan acupuncture treatment measurement during the 45-90 minute timeframe, while no needles were retained during the sham acupuncture group given that no needle penetration occurred during sham acupuncture. Clearly then, PET scans during that 45-90 minute period involve one group receiving an active treatment (given that needles were in their skin) while the sham group received inactive treatment (given that no needles were present). It seems obvious to me that there will be neurobiological differences between a group of people being measured while needles are inserted into them and a group of people who do not have needles in them, so their results are not surprising. Additionally, even though subjects may have not know which group they were in (they had to have had no prior acupuncture experience to participate), they quite likely were aware of whether or not needles remained in place during the PET scans, especially given the fact that both treatment groups involved placement on the head and ear. This knowledge could provide an explanation for the differences in treatment groups and is not addressed in the study. As such, even though the subjects were ignorant of whether or not they were receiving placebo treatment or not, the same cannot be said of their ignorance of the presence of needles placed in their body during PET scans.

What I find especially interesting about this study is the discussion of opponents of acupuncture in the introduction. The researchers wrote:

"Recent controversy in the field of acupuncture research was generated when several large scale randomized controlled trials in chronic pain patients failed to show superiority of acupuncture over sham acupuncture methods. This has led opponents of acupuncture therapy to suggest that it is no more effective than a placebo intervention."

I fail to see why one needs to be an opponent of acupuncture therapy to suggest exactly what the large scale randomized controlled trials are suggesting - that acupuncture therapy is not superior to placebo intervention. This sentence seems to indicate potential bias on the part of the researchers in this study. The data from these studies are very clear.

If the clinical results between acupuncture and placebo acupuncture are the same, it seems to me that potential side-effects are far more important than the fact that acupuncture and placebo acupuncture potentially operate via different mechanisms. This difference in mechanisms is irrelevant, or at least far less relevant than clinical results or side effects. It could be argued that different types of placebo acupuncture have different neurochemical mechanisms of action as well, but thus far no study has documented these potential differences. This study is weak in that it only compares two different treatments. If the study had used acupuncture and two different types of placebo acupuncture that had already been established through trials to have similar clinical results, and then shown that the mechanism of action for the placebo acupuncture was the same while the acupuncture group had a different mechanism, then the results would be more convincing.

The researchers indicated that previous studies indicated that the neurobiological response to acupuncture was distinct from pain and sham acupuncture, but one of the articles [5] I read in support of this claim (there were three total, and all appeared to be from the same group of people as evidenced by common authors. I read the newest one.) failed to blind subjects to which treatment they were receiving and thus is poor evidence to support their claim. Instead, this seems to support evidence that there is a different neurobiological response in individuals who know they are receiving acupuncture or a placebo, which is to be expected.

Regardless, it seems fairly obvious to me that measuring neurobiological responses in a PET scan while some subjects have needles inserted during the scan and others do not is measuring a neurobiological response to needles being in the skin versus not in the skin.  Sticking needles in subjects would likely provoke a different neurochemical response in subjects when compared to placebo acupuncture, which involved no needle insertion. So, if you do two different physical things to people, this provokes different neurochemical responses. Didn't we already know this? At least this study does not argue that acupuncture and placebo acupuncture have different effects. Instead, it argues that acupuncture and placebo acupuncture have different mechanisms. My less than dignified response is, "So what?"

 

1. Brinkhaus B., Witt CM, Jena S, Linde K, Streng A, Wagenpfeil S, Irnich D, Walther HU, Melchart D, Willich SN. Acupuncture in patients with chronic low back pain: a randomized controlled trial. Arch. Intern. Med. 2006;166:450-457.

2. Linde K, Streng A, Jurgens S, Hoppe A, Brinkhaus B, Witt C, Wagenpfeil S, Pfaffenrath V, Hammes MG, Weidenhammer W, Willich SN, Melchart D. Acupuncture for patients with migraine: a randomized controlled trial. JAMA 2005;293:2118-2125.

3. Melchart D, Streng A, Hoppe A, Brinkhaus B, Witt C,Wagenpfeil S, Pfaffenrath V, Hammes M, Hummelsberger J, Irnich D, Weidenhammer W, Willich SN, Linde K. Acupuncture in patients with tension-type headache: randomized controlled trial. BMJ 2005;331:376-382.

4. Harris RE, Zubieta JK, Scott DJ, Napadow V, Gracely RH, Clauw DJ. Traditional Chinese acupuncture and placebo (sham) acupuncture are differentiated by their effects on μ-opioid receptors (MORs) NeuroImage 2009;47:1077-1085

5. Napadow V, Kettner N, Liu J, Li M, Kwong KK, Vangel M, Makris N, Audette J, Hui KK. Hypothalamus and amygdala response to acupuncture stimuli in carpal tunnel syndrome. Pain 2007;130: 254-266.

 

Christina Stephens, OTD/s blogs at www.ziztur.com

 

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written by MadScientist, August 12, 2009
One item which comes to mind is: *what* is actually being measured by the PET? How is the claimed increased morphioid binding potential measured and is it a specific test? Without such details the claims are essentially just trying to give some credence to the woo-woo by using fancy gizmos.

In Positron Emission Tomography you inject a small amount of a radionuclide which generates positrons. The positron almost instantaneously annihilates itself and an electron and two gamma rays are emitted. It is the gamma radiation which is detected by the instrument. Using geometry and a variety of mathematical models the points at which gamma rays are originating can be estimated and an image produced. If you can somehow get the radionuclide to preferably accumulate in different parts of the brain then you can measure more radiation from that region. That's all that PET does and is all that it can do, so any claims about increased receptor affinity or whatever have to be backed up with a series of (usually other peoples') work demonstrating the claimed specificity.
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written by randi, August 12, 2009
While I am grateful to have Ms. Stephens' thoughtful analysis of the attempted acupuncture defense that has been going on, I'm alarmed that SWIFT may be taken over by this subject...! My personal interest in the acupuncture discussion is understandable, I believe, given my present situation, and resulted in my finding several disturbing endorsements of this quackery by prominent agencies. There are careers, large amounts of money, prestige, and national pride at stake here, and the effort reported and commented on by Ms. Stephens seems - to me - to be yet another desperate attempt to save the "art" of needling from its inevitable doom... Certainly, the fact that this latest effort on which Christina reports was not double-blinded, makes it impotent. That's "impotent," not "important"! Thank you, Christina!
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How sham is sham acupuncture?
written by RobbieD, August 13, 2009
Whilst the sham acupuncture in this new study did not involve penetration of the skin, did the sham acupuncture in the studies which showed no significant different with 'traditional' acupuncture penetrate the skin? And if this sham acupuncture did not penetrate the skin how was it done? How could people think they were getting acupuncture if they were not pricked by needles?
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written by ThinkTank, August 13, 2009
After reading only the title, I assumed that there was a plausible mechanism for this. A long course of acupuncture, with progressively blunter needles.

You'll get used to it eventually smilies/grin.gif
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written by GeekGoddess, August 13, 2009
"Recent controversy in the field of acupuncture research was generated when several large scale randomized controlled trials in chronic pain patients failed to show superiority of acupuncture over sham acupuncture methods. This has led opponents of acupuncture therapy to suggest that it is no more effective than a placebo intervention.


You pointed out the obviously bias in this statement.

This reminds me of a previous discussion where the chiropractic claimed that placebo acupuncture (where toothpicks were used inside of the needle sleeves so that the victim patients were feeling a prick of some kind) were JUST AS GOOD as real acupuncture and could be a viable treatment. He took the lack of difference between real and sham acupuncture to suggested that it validated acupuncture.


smilies/sad.gif
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sham acupuncture
written by garyg, August 13, 2009
I presume that one could produce sham acupuncture by sticking needles (or toothpicks)
in random locations (or locations deliberately chosen not to be along the "meridians"
claimed to exist by acupuncture devotees).

But, like other proponents of woo, some proponents will say you also need moxibustion
(burning herbs) during acupuncture.

They should be told: "how us the meridians! Show us qi!"
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answers
written by ziztur, August 13, 2009
@Randi - True! Typically I decide to write an analysis by checking out headlines on various news sources, but especially ScienceDaily's "alternative medicine" section. Whenever a new article comes out, I pounce on it. So, I'm basically just following a headline trend.

@Robbie - The sham acupuncture in these studies is the same as the sham protocol in Harris et al 2005 ("Treatment of Fibromyalgia with Formula Acupuncture: Investigation of Needle Placement, Needle Stimulation, and Treatment Frequency") and involves non-penetrative superficial skin pricking at non-acupuncture points. The patients were said to be blindfolded during the acupuncture and sham acupuncture sessions, though I still maintain that even with blindfolding, it is likely people could have been aware of whether or not needles were left in them during the 45-90 minute PET scan. Other placebo vs "real" acupuncture studies have used a variety of techniques for the placebo arm - blunt needles that withdraw into the skin placed on acupuncture points, those same needles placed on non-acupuncture points, acupuncture needles being inserted on non-acupuncture points, etc. It doesn't seem to matter where or how exactly you poke people, so long as they are being poked.

Given that, I conclude that it is simply unethical to subject individuals to an invasive procedure such as acupuncture when a non-invasive procedure has the same outcome.
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Knowing about the needles
written by gerastuff, August 13, 2009
As many have already pointed out, it is of vital importance to know wether the needles were left applied to a group of patients and removed in the other, because changes in the PET Scan are precisely what you would expect from leaving a pain stimulus applied.

Let me explain, the nociceptors (neural receptors in charge of reporting pain to the brain) do not "get used" to pain, meaningly they never stop reporting pain to higher levels in the nervous system BUT the Central Nervous system can, and does modulate the answer to pain by activating special spots to release inner opioids and suppress directly the sensation by means of acting in the neurons of the spinal cord that are being stimulated by nociceptors. If this crucial difference about the needles is not disclosed and actually happened it wouldn't surprise me at all the results of this study, in fact it would be only confirming what we know about pain modulation.
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The needles, quote from the article
written by ziztur, August 13, 2009
The needles were in fact left in during the PET scans. To quote directly from the article for ultimate clarification:


After needle insertion and manipulation,
scans from 45 to 90 min during PET1 were used as the short-term
treatment measurement (i.e. treatment1). During minutes 45 to 90,
needles were retained in the TA group, whereas no needles were
present in the SA group since SA did not involve skin penetration.

So gerastuff, you are absolutely correct. Chinese acupuncture does not seem to effect the brain's ability to regulate pain. What we are seeing in this study is the brain regulating pain as it already does on its own.
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...
written by Skemono, August 13, 2009
the study does not mention any blinding of the researchers, making it quite likely that the researchers were unblinded, which could have an effect on the study results.

In fact, it's almost certain. The study indicated that the "real" acupuncture and "sham" acupuncture were delivered at different points on the body--"real" acupuncture had needles penetrating "actual" acupuncture points on the body, while "sham" acupuncture had non-piercing needles (or something) poking points nearby the "actual" acupuncture points.

Since the person administering these would probably know whether it was "real" or "fake", it probably wasn't double-blind.

I suppose they could have made it double-blind if they hired people who didn't know anything about acupuncture, assigned them at random to the groups, and gave them the charts for which points to poke, and the researchers were themselves blinded to who was in what group... but there wasn't any mention of that.

Also, the study indicated (once again) that there's no difference in pain reduction between "real" and "fake" acupuncture. The conclusion says
there were no statistically significant differences in pain reduction between TA and SA (p>0.50).

(TA = Traditional Acupuncture, SA = Sham Acupuncture)
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Headlines
written by RobbieD, August 14, 2009
So the headlines are unsupported by the evidence. More bad science supports alternative 'medicine'.
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written by The SkepDoc, August 14, 2009
Was there an "exit poll" to determine whether patients could guess which group they were in?
Also, the whole rationale of the experiment bothers me. If there was no difference between true and sham acupuncture in previous studies, why did they think they would find a difference in receptors between the groups?
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written by Skemono, August 15, 2009
Was there an "exit poll" to determine whether patients could guess which group they were in?

Yes. Neither group could accurately guess which therapy they had received. The single-blinding did seem to work, but the apparent lack of double-blinding concerns me.
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Accupuncture rules
written by Lower Back Tattoo Art, August 15, 2009
Never tried acupuncture theraphy before...

Lower Back Tattoo Art
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My views and thoughts
written by Trisha11, August 17, 2009
Although I’m a bit skeptical about the form of treatment, but however after observing the progress one of my friend has made from his joint pain problems and muscle fatigues, I’m beginning to put interest in it. My advice is to look for qualified practitioners who have years of experience, so that you can trust and confidence in it.

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written by The SkepDoc, August 17, 2009
Trisha11,
Observing progress does not prove the progress was due to the treatment. Such symptoms typically fluctuate over time and might have improved through the natural course of disease or for other reasons.There is no acceptable evidence that acupuncture is better than placebo for joint pain problems and muscle fatigues.
If a treatment is not better than placebo, the only advantage to finding an experienced practitioner is that he may have learned how to elicit a placebo response more effectively.
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written by Skemono, August 17, 2009
For anyone interested, David Gorski at Science-Based Medicine has a post up about this study now, too:
http://www.sciencebasedmedicine.org/?p=733
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Inacupuncture
written by mjr, August 18, 2009
I don't understand why people care about "sham" acupuncture. Just use needles and put 'em in at random. Because I got interested in acupuncture woo-woo a few years ago, I bought a box of needles on Ebay (they are super cheap!) and some alcohol swabs, and stuck them into my arm in a few places. It's interesting - you instinctively "hunt" for spots where there isn't a nerve as it's going in. I suspect an acupuncturist subliminally monitors for a flinch response. When the needle is twirled, it sort of "drills" in because of the way it's flattened at the tip - it's completely painless. The hole is so small and fine that it leaves only a little dot that fades in 10 minutes or so.

After my short session of self-u-puncture, I was the same; i.e.: still an asshole. So it had no effect that I can report.

Still - time to nip the whole thing in the bud: measure 'acupuncture' against 'a bunch of needles stuck in someone' at random. That'd control out whether there's any actual theory behind acupuncture that means anything. Control that out and it's exposed as bullshit. I don't understand why they can't get 100 patients who'd undergo either acupuncture or random needles stuck someplace - after all, that's what acupuncture is, too.

Has anyone ever studied whether acupuncturists are consistent in their diagnosis, recommendations, and treatment? I.e.: do they all stick their needles in the same spots or do they disagree among eachother?

I can't believe it's 2009 and people are still taking this bullshit seriously.
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Screw medical ethics
written by mjr, August 18, 2009
Comment I forgot to make on previous: several doctors I've discussed this with defend this kind of study by saying that it's against medical ethics to actually perform a full fake "treatment" - i.e.: to actually stick needles in someone. WTF? But these same doctors stand aside and work at hospitals that host acupuncture and other energy medicine woo-woo? What's "medical ethics" about implicitly encouraging something claimed to be a healing practice that is known to have completely empty intellectual underpinnings? You can't have it both ways, doctors!
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written by The SkepDoc, August 18, 2009
Different systems of acupuncture use different acupuncture points and even specify different numbers of meridians. There have been a number of studies comparing needles inserted at acupuncture points to needles inserted at random. It makes no difference where you stick the needle. It makes no difference whether you penetrate the skin or use needles at all. Toothpicks and electric stimulation work just as well. The one thing that seems to make a difference is whether the patient believes he got the real thing.
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