By Ross Charles, M.D.
A constant, unrelenting, burning pain. This is what 73-year-old Ture J. experienced for 48 years after losing his right arm in a car accident.
Ture – who asked to be identified by his first name only – had what doctors call phantom limb pain or PLP. It’s what happens when the brain struggles to interpret the loss of a limb and fails. The absence of sensation is interpreted as pain – a clenching of a fist that no longer exists.
Over the years, various methods have arisen to help amputees deal with this condition. But for Ture, who tried multiple medications, as well as the famous “mirror therapy” that fools the brain by simulating the presence of the missing limb using a mirror box, nothing provided relief.
Nothing, that is, until he volunteered to be part of an experiment to test a new approach.
Doctors attached electrodes to the nerve endings in what remained of his arm. They used a video camera to project an image of Ture onto a television screen in front of him.
And then they created his new arm.
This new, computer-generated arm existed only in the pixels of the television screen. But Ture could control it with the nerves he had not been able to use for decades.
And with the use, came relief. After 12 weekly sessions, he reported a decrease in pain by more than 75 percent. In addition, for several weeks after the sessions, he remained completely pain free.
“After these 48 years, it is the first time I haven’t had pain at all. It’s fantastic,” he said. “Sometimes at night, when I lay in my bed and have no pain, it so, so fantastic. It’s indescribable.”
The Swedish team behind the findings, published Tuesday in the journal Frontiers in Neuroscience, hopes that this approach will make a difference for many more with PLP, which is estimated to affect more than 70 percent of amputees.
The virtual reality “trick” they employ involves creating virtual arm movements by translating the electrical activity in muscle into a computerized image – a technique called augmented reality. A patient spends up to an hour per week in front of the screen, utilizing various games and application engaging the virtual limb.
“We are making the rehab process fun and engaging,” said Max Ortiz-Catalan, the primary author of this study and a PhD candidate at Chalmers University of Technology. “A patient can be sitting for a couple of hours playing games.”
“This shows great promise,” said Dr. Vilayanur Ramachandran, director of the Center for Brain and Cognition at the University of San Diego, who was not involved with the study. “It is a really ingenious technique that they’ve used. It requires a larger and more extensive study, as the authors themselves acknowledge.”
Still, like other approaches to PLP, it may not work for everyone. Ortiz-Catalan said the technology is only useful for patients who have enough muscle remaining above the site of amputation. So it may not work for those with high amputations, such as shoulder amputations.
But more research is coming, he said. A clinical study is underway with three other regional hospitals and various clinics across Europe.
For the time being, it is difficult to say for sure what the future holds for this approach. But while the evidence presented in this study is limited to one person, the availability of this tool to combat the problem may one day be a welcome addition for the millions of amputees suffering from this common condition.
More research is needed. But for many like Ture, the clinical trials which are already underway may point the way to relief.