Better prosthetics can vastly improve quality of life for people with amputations. (Credit: Imperial College of London)

Scientists implanted electrodes in amputees’ stumps for better prosthetic control — with promising results. The early-stage research involved relocating nerves in patients’ remaining arms before implanting wirelessly chargeable electrodes and fitting new prosthetic arms.

In the two years after surgery, the patients found they could move their prosthetic arms more easily and with better accuracy and precision. This in turn greatly improved their quality of life.

The researchers say their study suggests that combining advanced surgery with cutting-edge technology can benefit people with amputations, and is a promising path for future prosthetic tech.

However, the signals between the stump and the electrodes in the socket are easily disrupted: unusual movement, moisture from sweat, or swelling and rubbing of tissue can all cause malfunction which can be frustrating and embarrassing for patients.

Researchers connected electrodes to nerves and muscles in the stumps to give users more control over movement, and to let the prosthetic ‘feel’ deeper muscles to get a better idea of the precise movements wanted by the user. They found that patients had far better control of their movements, and the prosthetics themselves followed instructions more reliably via their muscles.

They also found that, despite requiring surgery, rehabilitation took far less time than with current prosthetics. Fitting the socket was easier as there was no need to place surface electrodes between sockets and residual limbs, and sweating didn’t influence the level of control patients had over their prosthetics, or the quality and precision of the movements.

In addition, the scientists plan to further improve the man-machine interface by giving prosthetics the power of sensing their environment.