Researchers have found that a new nerve interface technology endows upper limb amputees with greater control and precision when using prosthetic hands. The interface, which worked for almost a year without adjustments in four limb amputees, could improve the durability of upper limb prostheses and enhance the quality of life for patients with upper limb loss, including by potentially reducing pre-existing pain. Peripheral nerve interfaces control neuroprostheses by registering signals from nerves in the remaining limb and translating them into movements. Nerve interfaces allow people who have lost limbs to intuitively control prosthetic replacements and to sense pressure and touch. However, many interfaces lose their function over time and require readjustment, and most platforms give implanted amputees only a limited range of independent movements. Phillip Vu and colleagues had previously created the regenerative peripheral nerve interface (RPNI) - an implanted interface that offers superior fine motor control of prosthetic hands. The RPNIs consist of a peripheral nerve that has been cut and implanted into a graft of muscle, which then regenerates and develops nerves and blood vessels over three months. In this study, the scientists implanted their RPNIs into four upper limb amputees and tested their durability and function. The RPNIs allowed the participants to make quick and complex finger and thumb movements with a prosthetic hand in real-time. The individuals also performed well in functional tests, such as grasping and moving small objects, and the interface worked for up to 300 days without requiring recalibration. Vu et al. caution that further studies are needed to compare the benefits of RPNIs with other surgical approaches.
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Journal
Science Translational Medicine