September 24, 2010

Study Claims Touching Injuries Could Reduce Pain

When a person grabs their hand, leg, or shoulder after an injury, it may not just be a gut reaction--it could actually reduce the amount of pain he or she feels, according to a new study.

In a study that was published online Thursday in the journal Current Biology, researchers from the University College, London (UCL) Institute of Cognitive Neuroscience report that by touching an injured limb or area, a person allows his or her brain to put together an updated picture of the body as a whole. This, then, can help reduce the perceptions of acute pain, they claim.

"Pain is quite an important, but also complicated, experience and can be caused in many different ways," UCL professor and study co-author Patrick Haggard said in a statement. "We show that levels of acute pain depend not just on the signals sent to the brain, but also on how the brain integrates these signals into a coherent representation of the body as a whole."

To test the phenomenon, Haggard and his colleague Marjolein Kammers used a technique known as thermal grill illusion (TGI), which can simulate pain without actually causing physical injury.

"The TGI is one of the best-established laboratory methods for studying pain perception," Haggard said. "In our version, the index and ring fingers are placed in warm water and the middle finger in cold water. This generates a paradoxical feeling that the middle finger is painfully hot."

In their study, Haggard and Kammers induced TGI on both hands of each subject, and found that when the three fingers that were used in the process from one hand were touched together with the corresponding fingers on the other, the sensation of painful heat in the middle figures was reduced by nearly two-thirds (64%).

"That relief didn't come when only one hand was placed under TGI conditions," according to a press release posted to the UCL website. "Partial self-touch in which only one or two fingers were pressed against each other didn't work either. Nor did it work to press the affected hand against an experimenter's hand that had also been warmed and cooled in the same way."

In fact, according to their study, "TGI was reduced only when thermosensory and tactile information from all three fingers was fully integrated. That is, TGI reduction required a highly coherent somatosensory pattern, including coherence between tactile and thermal patterns and coherence of stimuli between the two hands."

According to BBC News, Haggard and Kammers are now looking for ways to apply this information in order to help duplicate the effects in other parts of the body. Furthermore, as the UCL press release says, the research may help lead to "a better understanding of the brain mechanisms involved in chronic pain as well."


On the Net: