A Novel Therapy for Treating Phantom Limb Pain
Mirror therapy has the potential to relieve the discomfort felt by many who have lost a limb, including injured service members returning home from military conflicts overseas.
Each year, scores of service members return home from military conflicts as amputees. Some have lost more than one limb, and all have to learn to readjust as they begin to rebuild their lives back home. Unfortunately, many of these individuals (as well as people who’ve lost a limb in accidents or for other reasons) suffer from a condition called phantom limb pain (PLP), whereby the patient feels pain in the lost limb.
“Phantom limb pain continues to be a common problem for most individuals with acquired limb amputation, including many of our wounded soldiers,” said Paul F. Pasquina, MD, chair, Department of Physical Medicine and Rehabilitation, F. Hebert School of Medicine, Uniformed Services University of the Health Sciences in Bethesda, Maryland. “The severity of phantom limb pain seems to be very variable depending on the person.”
Basically, PLP is perceived pain from a limb that no longer exists. In terms of the amount of pain that a patient experiences, there appears to be no correlation with the location or the level of the amputation, Dr. Pasquina said. “While there have been some reports that it might be more problematic for individuals with upper limb or hand loss, we have not observed this in our wounded warriors,” he added.
Aggressive pre- and post-operative pain management strategies that encompass a combination of different therapies have been effective in treating the pain, he noted. Besides medication, non-pharmacological strategies include acupuncture, meditation, physical modalities such as heat, ice, and electrical stimulation (TENS), and getting back to function using a prosthesis.
“Generally, most of our patients report decreasing pain over time and with therapy,” Dr. Pasquina said.
One treatment, called mirror therapy, holds promise for treating PLP, he explained. “We have found benefit from the use of mirror therapy,” he said. “And it is offered to all our service members who we see with phantom limb pain.”
How This Simple Technique Works
Since the limb no longer exists, the brain improperly processes where the pain is coming from and as a result can't stop it. In mirror therapy, patients view the reflection of their good limb in a mirror and move it. When the brain observes the intact limb moving, the reflection gives the brain visual feedback it wasn't receiving previously and relieves the pain.
Put another way, say a patient has pain from a perceived cramp in a tightly-clenched fist that no longer exists. By watching the action of the still intact hand clenching and unclenching in the mirror, the brain receives the visual feedback it needs to "unclench" the non-existent/phantom hand. It's a little like scratching an itch that couldn't be accessed.The image stops the pain.
In a controlled trial to investigate the use of mirror therapy to treat PLP, CDR Jack Tsao, MD, DPhil, Director of Traumatic Brain Injury Programs for the US Navy Bureau of Medicine and Surgery in Washington, DC (pictured above), and his colleagues divided this form of therapy into three versions: full mirror, covered mirror (so that the reflection of the intact limb was blocked), and mental visualization of the phantom limb moving.
After a month of treatment, 100% of the patients in the mirror group reported a decrease in their pain. But only 17% of the participants in the covered mirror group and 33% of the participants in the mental visualization group reported a decrease in their pain.
David Shepetofsky, a physical therapist at Staten Island University Hospital in Staten Island, New York, says mirror therapy has been used successfully on a handful of his patients. “The greatest use and positive effect of mirror therapy is more of a body image use rather than a pain-decreasing modality,” he said.
Mr. Shepetofsky theorizes that in terms of pain reduction with mirror therapy, it may be that when patients visualize the lost limb while “moving” it might result in a slight decrease in the way the patient perceives the pain. “I am not convinced but I do think there are great psychological benefits from the patient having the experience of mirror therapy,” he explained.
Despite mirror therapy and other forms of treatment, phantom limb pain continues to be a problem for some patients. “Therefore we are actively pursuing additional research to better understand the central and peripheral nerve changes associated with acquired limb loss,” Dr. Pasquina explained. “We hope that by better understanding the underlying mechanisms behind the pain, we might be better able to target future treatments.”
To view a video of an amputee experiencing mirror therapy, click here.