Examining Brain Changes Using Functional Magnetic Resonance Imaging (fMRI) in Amputees With Phantom Limb Pain Following Mirror Therapy

Almost everyone who has a traumatic limb amputated will experience a phantom limb - the vivid impression that the limb not only still is present, but also in many cases, painful. Preliminary data from study WRAMC WU# 05-71034, "Pilot study to assess the efficacy of mirror-box and mental visualization treatments on phantom limb pain" demonstrates that 4 weeks of mirror therapy is effective for treating phantom limb pain (PLP) and suggests that vision is a key component modulating PLP and may be the explanation for the efficacy of mirror therapy, as subjects view the reflected image of their intact limb while attempting to move the amputated, or phantom, limb. We propose conducting a study using functional magnetic resonance imaging (fMRI) to identify brain regions critical for the mirror effect and to study the relationship of visual activation to the sensation of phantom pain. Subjects will have an fMRI scan prior to starting therapy, 2 weeks after starting mirror therapy and again after 4 weeks of mirror therapy. Data will be gathered daily on the number of episodes of phantom limb pain, the average length of episodes, and the average intensity of pain.