Beyond Ramachandran's mirror: A simple video-based intervention for phantom limb pain in unilateral and bilateral amputees -- David Peterzell, School of Psychology, Fielding Graduate University
Ramachandran and others have shown, in well-known studies, that viewing a mirror reflection of one's moving intact limb reduces phantom limb pain in some single-limb amputees. Also, mirror interventions may enhance recovery from unilateral hemiparesis following stroke and other conditions. However, mirror therapy is ineffective for some single-limb amputees, and cannot treat bilateral amputations or paralysis. Additionally, many single-limb amputees with weak or damaged remaining limbs become fatigued by moving limbs during treatment. I find that a simple video may achieve effects similar to the mirror without causing fatigue, and can extend to bilaterals. First, a video was created of an intact individual's legs and feet, with the individual flexing his ankles, feet, and toes up and down. This flexing was periodic with each cycle occurring every 2 seconds. The flexing was filmed from a subjective point of view, looking down from eye level upon the legs and feet. Patients observed the repeating video loop on a 13-inch laptop computer for ten minutes. Each observer placed the computer on his or her lap and imagined that the flexing limbs were his or her own, and that he or she was causing the flexing. When individuals experienced the illusion of internal (egocentric) locus of control, they experienced strong phantom sensations (paresthesias) and a sense of movement in the missing or paralyzed legs. The intervention led to significant measurable, apparently permanent pain reduction in two bilateral amputees, and two unilateral amputees who had not benefitted from using the simple mirror. A stroke patient reported sensing movement in his paralyzed legs. Some non-amputee normals experience some of the following in their legs while observing the video: tingling, numbness, tickling, pressure, heat, cold, or involuntary movement. It seems likely that video clips mimic the effects of Ramachandran's mirror therapy, and work for the same reasons. Preliminary results, however, suggest that this video technique may extend mirror-like treatment to individuals who cannot benefit from the simple mirror.
Peterzell, D.H. (2012) Beyond Ramachandran's mirror: A simple video-based intervention for phantom limb pain in unilateral and bilateral amputees. Vision Sciences Society 12th Annual Meeting, Naples FL, May 16, 2011.