Mirrors used to treat amputees’ pain

In his mind, Senior Airman Christian Ivory, 22, still clutches the grenade that blew up his right hand in November.

Though the grenade destroyed his hand, which had to be amputated, he said the sharp, burning sensation that runs through his missing limb can’t be just his imagination.

“It feels like my hand is still holding something, like I’m still gripping something,” he said. “You know how when your hand falls asleep and it burns when it’s starting to wake back up? It’s like that, only about 20 times worse. It hurts like hell.”

A neurologist working with amputees at Walter Reed Army Medical Center believes he has “rediscovered” a cure for the phenomenon known as “phantom limb pain,” as well as a theory for what causes it.

“My feeling is if something works, there has to be a scientific explanation for it,” said Navy Cmdr. Jack Tsao, associate professor of neurology at the Uniformed Services University of the Health Sciences.

Sitting on a bench at Walter Reed with a mirror between his knees, Christian opens and closes his right hand so he can see it reflected in the mirror. In the mirror, it looks as if his missing right hand is also opening and closing. On the other side of the mirror, where he can’t see it, Christian works to “open” and “close” the missing hand.

“When I first got here, I couldn’t move the muscles in my arm,” he said, because he feared the pain. “The mirror helps. It doesn’t hurt to move it anymore.”

Tsao recalled reading about mirror therapy in graduate school. Vilayanur Ramachandran, a neuroscientist at the University of California, had done a study that found mirrors helped people who had lost their upper limbs recover from their phantom pain through a visual illusion that recreated the missing limb.

“Just by watching it, it would induce the physical feeling of movement,” Tsao said.

Ramachandran didn’t know why the method worked, and he was unable to test the theory further for lack of funding and amputees. However, he did find that the therapy worked even 15 years after a person had lost a limb.

No one had done a controlled study since Ramachandran’s work in the mid-1990s, Tsao said.

Tsao, unfortunately, has no shortage of amputees. He put in a proposal and received funding.

Mirrors are cheap and can be used anywhere, so money was not an issue. Because Ramachandran had worked with upper-limb amputees, Tsao decided to try the therapy on troops who had lost lower limbs. The first study began in January 2006.

Tsao had one group of six amputees try to move their phantom foot using the mirror. Though the patients obviously couldn’t move what wasn’t there, the muscles that caused the movement were often still there — and in the mirror, the missing limb appeared to be moving.

For a second group, he covered the mirror and had the service members try to move their missing foot without being able to see their reflection.

Tsao had the last six amputees try to move their missing foot while blindfolded.

Everyone in the mirror group improved: The phantom pain either went away or decreased. But those in the other two groups stayed the same, and a few actually got worse.

“Initially, we thought all the therapies might be equally effective,” Tsao said. “We did not expect anyone to get worse.”

After the study, some of the amputees who had not used the mirror therapy in his study did it voluntarily, and all but one improved.

Then Tsao went to work on his theory. Basically, a person’s brain sends a signal to cause the hand to do something — make a fist, catch a ball, pull back from heat. In amputees, he said, the brain doesn’t understand that the limb is gone and continues to send a signal.

In Ivory’s case, that last signal seems to be stuck. He and some friends were messing around with a homemade grenade near his base in Italy after a Veterans Day barbecue. One of his buddies had made it, he said, with three quarter-sticks of dynamite wrapped in black powder.

Ivory brought his arm back to throw it, but the grenade exploded during the windup. He said it feels as if he’s still holding it, which causes painful cramping.

Tsao said treating phantom pain visually might work because visual feedback may tamp down other signals the brain receives.

He said most amputees have phantom pain, and it often feels to them as if they’re stuck in their last action with that limb. For example, a Marine he treated lost his hand while firing his rifle. He feels as if his finger is eternally pulling the trigger.

Tsao theorizes that the memory “is so traumatic that it burns into the memory bank. The mirror clears the memory bank and neurons start making new connections.” He calls the theory “pro-perceptive memory.”

He is now working with nine patients, including Ivory, for a study of upper-limb amputees. Ivory’s therapy will last for four weeks, with 15-minute sessions each day.

Tsao is also working with double amputees, with his research assistants Katie Hughes and Lindsay Hussey using their own limbs to re-create patients’ missing limbs.

Next, Tsao wants to compare before and after MRI scans of amputees who have gone through mirror therapy to see if there are visible changes as the brain adjusts to the new signals.

About once a week, Tsao said, he receives e-mails from patients or doctors who want to know about the therapy, and he thinks it could be of great use to land-mine victims in Third World countries such as Cambodia, because the therapy is cheap and easy.

“It’s personally very gratifying to see people get better in this clinic,” he said. “To see it go from experimental to an actual treatment they use is a testament to the open-mindedness of this staff and the patients.”

Source - Marine Corps Times

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