Researchers report an amputation method that enabled greater precision of movement and a reduction in pain in a prospective study. Typical amputation procedures disrupt neuromuscular relationships and trigger reorganization of motor circuits, potentially impairing motor coordination and leading to significant pain. Shriya S. Srinivasan, Hugh Herr, and colleagues explored the effects of an amputation approach called the agonist-antagonist myoneural interface (AMI). This surgical procedure couples a muscle pair for each joint below the amputation, restoring the physiological feedback produced when one of the pair contracts, in an attempt to mimic the reciprocal muscle relationships of a limb. In a nonblinded study, the authors compared outcomes for 15 individuals with AMI with seven patients who had undergone a traditional form of below-the-knee amputation in approximately the same time frame. Measures of muscle activity via electromyography revealed significant temporal coordination between activation of the muscle pair and intended movement of the phantom joint in individuals with AMI, an effect not present in most traditional amputation recipients. In surveys, individuals with AMI reported less pain than traditional amputation recipients. According to the authors, the AMI procedure could improve control of bionic prostheses for below-the-knee amputations and offers benefits regardless of the type of prosthetic chosen.
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Article #20-19555: "Neural interfacing architecture enables enhanced motor control and residual limb functionality postamputation," by Shriya S. Srinivasan et al.
MEDIA CONTACT: Shriya S. Srinivasan, Massachusetts Institute of Technology, Cambridge, MA; email: < shriyas@mit.edu >
Proceedings of the National Academy of Sciences