Thought control brings pain into line
Brain imaging helps pain patients learn to reduce their own pain.
Researchers have managed to teach people suffering chronic pain to reduce their own discomfort simply by controlling their thoughts.
It's unclear how long the effect lasts, but the researchers hope that this approach could one day be used to treat chronic pain, which affects tens of millions of people in the United States alone and is a major reason for sick leave.
The team, led by Christopher deCharms, showed eight patients real-time functional magnetic resonance imaging, or fMRI, of the activity in their rostral anterior cingulate cortex (rACC), a part of the brain known to be involved with pain control. They asked participants to try to increase or decrease activity in this area, by focusing on their pain or by distracting themselves from it.
This isn't the first time that people have been shown to be able to control their brain activity simply through thought. Last year, Rainer Goebel, a brain researcher at the University of Maastricht in the Netherlands, showed that people could control a table-tennis computer game simply by watching fMRI brain scans (see ' Mental ping-pong could aid paraplegics'). But Goebel thinks deCharms's work is also important: "It's really new that they not only let people change their own brain activity but that they use that to treat pain patients," he says.
"I was struck by how the chronic pain patients were able to see the pain and take control of it," says Sean Mackey, an anaesthesiologist at Stanford University and co-author of the study.
One patient, 31-year old Laura Tibbitts, has been suffering from chronic pain in her shoulder blade area since she was thrown off a horse seven years ago. She says she sometimes felt reduced pain for hours after a session in the scanner. She can even reproduce the effect at home to some extent, she says, although it takes a lot of concentration to do so.
Patients used different strategies to reduce their rACC activity. Sometimes, Tibbitts says, she tried to focus on areas of her body where she didn't feel any pain. At other times, "I would literally imagine tiny people marching in my back and scooping the pain out," she says.
To test the possibility that people felt less pain simply because they were distracted while doing the experiment, the researchers asked some to reduce activity in a brain area not involved in pain perception. But these patients reported no improvement in their condition.
But the authors caution that the treatment didn't work equally well for everyone. "This means we have a lot of work to do before this can even be talked about as a possible therapeutic tool," Mackey says. He adds that the rACC isn't the only area known to be involved in pain perception. "Maybe for different people we should be looking at different brain regions," he says.
Whatever the case, the most important thing for Tibbitts was to see that chronic pain is real and can be controlled. "It was very validating and empowering," Tibbitts says.
The team is currently investigating the long-term effects of repeated fMRI training. DeCharms's company Omneuron, a biotech group in Menlo Park, California, has patents pending on real-time fMRI-based training methods.
- deCharms C., et al. Proc. Nat. Acad. Sci., 102. 18626 - 18631doi:10.1073/pnas.0505210102 http://www.pnas.org/cgi/doi/10.1073/pnas.0505210102 (2005).
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