Using mirror illusion to self-treat pain is feasible, Oregon study finds
Published: Tuesday, March 13, 2012, 7:00 AM
Olivia Bucks/The Oregonian
In mirror therapy, people who’ve lost a limb hold a mirror across the body so that it hides the missing limb and reflects an image of the intact, opposite-side limb in its place.
With a bit of trickery, most people readily succumb to the illusion that a rubber hand has replaced their own living appendage. When people who have lost an arm or leg view a mirror image of their intact limb, they can feel vivid sensations of touch and movement as if they were coming from the missing body part.
Studying such illusions is helping scientists understand the brain – and find new approaches for treating chronic pain and other neurological problems. Mirror therapy, for example, is proving to be an effective and simple treatment for phantom limb pain after amputation.
The technique is unbelievably simple: Patients hold a mirror across the body so that it hides the missing limb and reflects an image of the intact, opposite-side limb in its place. Patients are supposed to spend about 25 minutes a day moving the intact limb in the mirror, experiencing views of a functioning, pain-free limb. The illusion can powerful and startling, a patient told The Oregonian in a 2009 interview:
“When I pointed my toe, I felt a distinct sensation that my other heel was dragging across the bed covers,” she says. While rotating her left foot in circles, her big toe accidentally touched the mirror. But instead of feeling cool glass, “it felt as if my two toes were touching,” she says. “At some level, I know that didn’t happen, but I would vouch for that sensation as being real.”
A recently completed study at Oregon Health & Science University in Portland suggests that motivated individuals can use mirror therapy to treat themselves at home without the expense and inconvenience of having to visit a therapist for each session.
Psychologist Beth Darnall and physician Hong Li enlisted forty people with amputations and moderate to severe phantom pain. After two months, participants’ self-rated pain decreased by about 15 percent. (Subjects with more years of education reported better results: 37.5 percent median pain score reduction, compared with 4.1 percent among those with less education.)
A few early studies suggests that mirror therapy may help stroke patients recover function in paralyzed limbs, and reduce the symptoms of complex regional pain syndrome.