"This is a beautifully designed study that shows, without a doubt, that patients are helped by the mirror," says Vilayanur Ramachandran, a neuroscientist at the University of California at San Diego, who invented mirror treatment 11 years ago.
Tsao's study is the first to test the mirror approach in such a rigorous way - a key step for establishing scientific proof.
"It amazes me that nobody ever did follow-up studies" on Ramachandran's work, says Tsao, an associate professor of neurology at the Uniformed Services University of the Health Sciences, the military's medical school in Bethesda. A key reason was the scarcity of amputees in any one place. But with a steady stream of injured veterans from the wars in Iraq and Afghanistan, Walter Reed had enough for a study, Tsao said.
Ramachandran says Tsao's research could increase the popularity of the treatment, which is not widely used.
"People are suffering needlessly because they're not getting this treatment," says Ramachandran. "Given how easy and inexpensive this is, it's worth trying."
Since the study appeared, Tsao has heard from doctors and therapists around the country interested in trying mirrors with their patients.
The technique is remarkably simple. The patient sits on a flat surface with his legs straight out. He puts a rectangular, 6-foot-long mirror lengthwise between his legs, with the reflective side facing the intact limb.
He then moves his good leg and watches the movement in the mirror. The reflection creates the illusion of two whole limbs moving in unison. As this is happening, the patient imagines moving the amputated leg in the same way as the uninjured one.
Patients go through this process for 15 minutes a day for a month, using a range of leg movements.
Sitting on an exercise bench in Walter Reed's rehabilitation center, Paupore says mirror therapy saved him.
"The pain wasn't something I could learn to live with," he says.
A gentle man with a crew cut, Paupore joined the Army in 2004 out of a sense of patriotism. Before enlisting, he worked in a wine and beer warehouse in Traverse City, Mich.; he hopes to find work as a civil servant for the federal government.
The mechanisms behind phantom limb pain remain mysterious. The problem could stem from a kind of cortical confusion. The brain has specific regions devoted to receiving sensory input from the body. In an uninjured person, this information - temperature, position in space, hardness and so on - flows steadily from nerve endings to cortex.
