April 18, 2011 -- An optical illusion that harnesses the power of suggestion might one day deliver drug-free pain relief to arthritis sufferers, British researchers say.
Analgesic and anti-inflammatory pills and physical therapy are among traditional approaches to reducing or eliminating the aches and pains of chronic osteoarthritis, common among men and women older than 50. In recent years, many sufferers have tried complementary and alternative approaches such as yoga, massage and acupuncture to counter the pain and stiffness of the wear and tear on their joints.
Now, psychologists at the University of Nottingham say that they might have serendipitously stumbled upon a new, non-invasive way of turning down the pain dial by tapping into brain-body connections.
Arthritis Pain: Illusion Fools the Brain
They achieve relief by fooling the brain with something they call "illusory manipulation." It's similar to the "mirror therapy" administered to reduce phantom pain some amputees experience where their missing limbs used to be. A mirror and lens optically "resurrect" the missing limb; shrinking the image lessens the pain.
At an open house last April, University of Nottingham psychologists Roger Newport and Catherine Preston were demonstrating Mirage technology, which they developed to study how the brain processes visual and other sensory signals. Curious children took turns sticking their hands into the Mirage box and watching cool-looking illusions that make them seem to be wider, narrower, longer or shorter -- much like what happens when you stand in front of body-distorting mirrors in a fun house -- except that Mirage uses real-time video and computer-generated images projected onto a screen.
Youngsters can watch on-screen as one of the researchers gently pushes or pulls at their fingers. Through the magic of mirrors and computer effects, the on-screen image seems to show their fingers growing longer just as they're feeling the researcher pull, or shrinking as they feel the researcher push.
At one point, "the grandmother of one of the children wanted to have a go, but warned us to be gentle because of the arthritis in her fingers," said Preston, a psychologist now at Nottingham Trent University. "We were giving her a practical demonstration of illusory finger stretching when she announced, 'My finger doesn't hurt anymore' and asked whether she could take the machine home with her. We were just stunned. I don't know who was more surprised, her or us."
Arthritis Support-Group Volunteers Put Mirage to the Test
Intrigued by the grandmother's reaction, Preston and Newport, an associate psychology professor at the University of Nottingham, wanted to investigate further. They contacted a local osteoarthritis support group to find volunteers who might help determine more scientifically whether Mirage's effects were real, or just an illusion.
They recruited 20 volunteers, average age 70, with painful arthritis. With a hand in the Mirage box, volunteers' brains processed both the sensations they felt and what they saw on the screen. When they rated their pain, 85 percent of participants on average said it was halved. Pain vanished for six patients.
The results appeared in a letter to the editor in the March 29 online edition of the journal Rheumatology. In it, Newport and Preston suggested their method might prove useful "for promoting therapeutic exercise normally prevented by painful movement."
In a Mirage demonstration broadcast by BBC News, arthritis patient Pam Tegerdine said, "It was a very weird sensation, but as my finger was being 'stretched,' it felt more and more comfortable. I just wanted it to stay like that, to keep that image in my head. If this could lead to a drug-free treatment for arthritis, then that would be fantastic."
Arthritis Pain: Mirage Box Works, but How?
Although Newport and Preston didn't report how long the relief lasted, "such dramatic improvements must be considered good news, even if they provide only a temporary respite," Candida S. McCabe, who works at the Bath Centre for Pain Services at the Royal National Hospital for Rheumatic Diseases, wrote in an accompanying editorial.
She noted that although there was no control group, changes in pain levels occurred only when the researchers manipulated the painful areas of volunteers' hands. Manipulating the entire hand or non-painful areas had no effect, suggesting that "distraction alone did not influence patients' perception of pain."
The co-authors still cannot say how the device produces relief, nor could they rule out the placebo effect, but nope to learn more from additional studies. Although they didn't measure range of motion before and after using the box, some study subjects reported that they were able to move their fingers more freely after using Mirage.