A new study in the journal Pain suggests that hand pain may be reduced simply by crossing your arms, thereby confusing the brain's spatial mapping. It was a very small study, but it does give some interesting clues as to processes the brain uses to interpret pain.
Study Design and Results
Two experiments were performed using eight healthy volunteers. First, a laser was used to administer brief pain-producing pin pricks on the hands of the participants. Then the subjects crossed their arms and the pin pricks were repeated.
Participants rated their pain themselves and an electroencephalography (EEG) measured their brains' responses. Both measurements showed that there was less perception of pain when the arms were crossed.
In the second experiment, electrically evoked non-painful sensations were administered. Again, the researchers found that crossing the arms reduced the perception of the sensations.
Why would crossing your arms result in reduced pain perception? The scientists think it is because of conflicting information from two of the brain's image maps. For example, the brain has one map of the right hand itself and a second map of the external space around the right hand. The same is true for the left hand. When the arms are crossed, the maps become mismatched, with the right hand in the left hand's space and vice versa. As a result, the brain's information processing ability becomes weaker and there is less perception of stimuli like pain or touch.
Other than studies showing relief of phantom limb pain using mirrors, this study is the first evidence that it is possible to reduce pain by impeding the processes by which the brain localizes a harmful stimulus.
I'm always fascinated by any research that gives us a peek into how the brain works. We know that all pain comes from the brain, regardless of where in our bodies we feel it. So anything we can learn about how the brain processes pain is going to be helpful in developing new and more effective ways to reduce pain – whether it is through better medications or new therapies like mindfulness meditation.
Mirror therapy for phantom limb pain was the first clue that we might be able to trick or confuse our brains into thinking there is no pain. (You can see an interesting video demonstrating mirror therapy here: Treating 'phantom limb pain' with mirror therapy). This new study provides additional evidence that we may be able to change or retrain the brain when it comes to pain perception.
Before we get too excited, though, we have to remember:
- This was a very small study, using only eight people.
- All of the volunteers were healthy. None had a history of chronic hand pain.
- The painful stimulus was administered externally. It was not already existing internal pain.
- The degree of pain reduction was small.
I can't help but wonder whether crossing your arms would help pain from something like carpel tunnel syndrome. Since I don't have hand pain, I can't put that to the test. If you do, perhaps you could give it a try and let us know if you noticed any difference.
While crossing your arms might not be the answer for all – or even any – hand pain, I do think the research is useful in providing another small piece of the pain processing puzzle.
Gallace A, et al. The analgesic effect of crossing the arms. Pain. 2011(Jun);152(6):1418-1423.
Published On: October 26, 2011