Today’s conventional powered prosthetic arms usually have a few built-in electrodes that make contact with patient skin. These are good enough to open and close a simple claw, but for more nuanced control of prostheses with multiple degrees of freedom and individual fingers, a better approach is required. Implantable electrodes can gather a great deal more data from the electrical signals around the stump, but they require cables that protrude through the skin, a major limitation.
Now, researchers at Medical University of Vienna, Otto Bock Healthcare Products, Alfred Mann Foundation, and Imperial College London have come together to develop an implantable wireless system that allowed three amputees to use robotic arms in ways that are impossible using external electrodes.
The researchers implanted electrodes close to important nerves and muscles within the stumps of the three volunteers, which let them gather much stronger signals and interpret them appropriately. After following the amputees for more than two years, the researchers noted a much improved ability to use powered prosthetic arms and to do so with greater intuition. Moreover, rehab was easier and quicker compared with existing solutions because there’s no need to place and align electrodes nor as much work to adjust to the system. Fitting sockets was also easier since there is no need to consider electrodes and sweat did not affect the quality of the signals obtained.
All three of the amputees loved the new system and wanted to continue using it, which is very promising since most existing powered prostheses are generally still lacking in many aspects.
Study in journal Science Robotics: Long-term implant of intramuscular sensors and nerve transfers for wireless control of robotic arms in above-elbow amputees