Yet Another Acupuncture Experiment Overblown

Acupuncture being performed. From Wikipedia

A presentation is being given today at the 96th Scientific Assembly and Annual Meeting of the Radiological Society of North America.

A couple of media outlets have jumped on this presentation, titled “Influence of Acupuncture on Pain Modulation during Electrical Stimulation: An fMRI Study“.

The headline in the Telegraph reads: Acupuncture’s effect ‘isn’t just psychological’

In the Daily Mail it reads: Acupuncture is no placebo and does relieve pain, say scientists

The Telegraph headline is misleading, and the Daily Mail headline is just plain wrong. And, as I’ll point out, both are overstating the findings of the study, as are the scientists who performed it.

So first off, fMRI stands for Functional Magnetic Resonance Imaging. It is a type of MRI scan which can determine which parts of the brain become “activated” by measuring the amount of blood flow to each part of the brain.

It is a fascinating field of study, and in a future post I will explain the physics of MRI, but for now lets just say that fMRI is (somewhat) able to tell which parts of the brain “turn on” when you do certain tasks.

So what happened in this particular study is this: the authors got 18 healthy volunteers and shocked their ankle with an electric shock to induce pain. At the same time, they imaged their brain using fMRI.

Next, they took the same 18 people, performed acupuncture on them, and then shocked their ankle again and took another fMRI of their brain.

They compare the two images, before and after the acupuncture, to see which parts of the brain light up (or don’t) to see if they could see any differences in how the brain reacts to pain stimuli with and without acupuncture.

And wouldn’t you know it? They did see a difference. Their conclusion:

Activation of brain areas involved in pain modulation was significantly reduced or modulated under acupuncture and the majority of the detected areas were not influenced by the analyzed covariate. However, left anterior insular cortex and orbitofrontal / superior frontal gyrus activation was modulated by stimulus intensity. We hypothesize that insula activation seems to be correlated to the stimulus and pain intensity while the importance of frontal activation increases during acupuncture and may be an acupuncture specific effect.

Essentially, they found that after the acupuncture, parts of the brain which control pain were not activated as strongly. Not only that, but the affective response to pain (the frontal cortex) was changed after the acupuncture as well. Pretty convincing right?

No. It’s not . First off, a similar response has been shown by Wager et al. in 2004 that placebos induce the same effect.

Second, it has also been shown that expecting pain can alter one’s response to pain. This study had the volunteers get their ankle shocked first, then they got acupuncture and had to be shocked again. They were expecting the pain, so this may have affected the results.

Third, there was no control group. A proper study should have had a placebo type of acupuncture, such as pricking the skin with toothpicks (which has been done before) or placing the needles at non-acupuncture points. Or they should have tried some other type of pain relief, like massage or relaxation prior to the second shock, to see if there was any difference.

Fourth, the study only had 18 volunteers. To make a claim that acupuncture works based on such a small group is irresponsible.

Fifth (geez, five points?!) fMRI is not easy to gather accurate conclusions from. The workings of the brain are affected by many things and brain responses can be non-localized.

I am not refuting the results of the study, only the conclusions drawn by the authors and the media. The data itself is not surprising. In fact, it is exactly what you would expect since placebos have shown similar results. But to draw the conclusion that this is an acupuncture specific effect from this data is fallacious.