NEW YORK, May 17 (Reuters Health) -- Extensive use of a myoelectric prosthetic limb may help prevent 'phantom' limb pain, unpleasant sensations that seem to originate in an amputated limb, German researchers report.
The findings are promising because phantom limb pain is of unknown origin, and is difficult to treat.
Myoelectric prostheses involve the use of electrodes that receive signals from certain muscles and transmit those signals to a motor that operates the prosthesis. They are more complicated than a simple, cosmetic prosthesis, but they also offer the patient more function, such as a better ability to grasp objects.
Of 14 people who reported experiencing phantom limb pain after they lost an arm, those who used myoelectric prostheses for more than 8 hours a day had less phantom limb pain over time than those who did not use this type of prosthetic limb or who used one less frequently, according to a study from Dr. Martin Lotze of the University of Tubingen, Germany, and colleagues, published in the June issue of the journal Nature Neuroscience.
Brain scans also showed that patients who used a myoelectric prosthesis demonstrated less cortical reorganization than those who did not use one. Cortical reorganization, the reorganization of the "brain map" that governs how the brain registers sensations from various parts of the body, may be responsible for phantom limb pain.
The investigators write that "ongoing stimulation, muscular training of the stump, and visual feedback from the prosthesis may have a beneficial effect."
"Our data strongly suggest that extended use of a myoelectric prosthesis might reduce both cortical reorganization and phantom limb pain, a still relatively treatment-resistant disorder," the researchers conclude.
SOURCE: Nature Neuroscience 1999;2:501-502.
