New Technology Allows Control in Each Finger of Bionic Hand

For the first time, a person with an arm amputation can manipulate each and every finger of a bionic hand as if it was his own.

Prosthetic limbs are a common solution to regain function and appearance after losing an extremity, but they may be hard to control and are often limited to a couple of movements.

A study in Science Translational Medicine describes the first case of an individual whose body was surgically modified to incorporate implanted sensors and a skeletal implant. Artificial intelligence algorithms then translated the user’s intentions into the movement of the prosthesis.

The new prosthesis allows the patient to perform daily tasks, such as holding a cup, grabbing a piece of paper, or using a screwdriver, without prior training.

Remnant muscles in the residual limb are the preferred control source for bionic hands. However, at higher amputation levels, such as above the elbow, there are much fewer remaining muscles to command the many robotic joints needed to truly restore the function of an arm and hand.

A team of researchers reconfigured the residual limb and integrated sensors and a skeletal implant to connect with a prosthesis electrically and mechanically. By dissecting the peripheral nerves and redistributing them to new muscle targets used as biological amplifiers, the bionic prosthesis can now access much more information so the user can command many robotic joints at will.

The researchers attached the bionic hand using a titanium implant placed within the residual bone, which becomes strongly anchored, a technology known as osseointegration. Such skeletal attachment allows for a comfortable and more efficient mechanical connection of the prosthesis to the body, compared to using a socket that compresses the residual limb.

“A key feature of our work is that we have the possibility to clinically implement more refined surgical procedures and embed sensors in the neuromuscular constructs at the time of the surgery, which we then connect to the electronic system of the prosthesis via an osseointegrated interface. A.I. algorithms take care of the rest,” says lead researcher Professor Max Ortiz Catalan, Founding Director of the Center for Bionics and Pain Research (CBPR) in Sweden and Head of Neural Prosthetics Research at the Bionics Institute in Australia.

Research from 2020 ed by Ortiz Catalan describes cases of three patients living with mind-controlled arm prostheses. The cutting-edge bionic limbs were the first ones allowing amputees to experience a sensation of touch.

Bionic prostheses, however, remain costly and are associated with certain health risks, such as infections and bone fractures. Nevertheless, they are rapidly becoming more functional and reliable, giving hope to millions of people with amputations worldwide.