Bionic hand restores amputee's sense of touch

A bionic hand that allows its wearer to actually feel what the prosthetic is touching has been tested for the first time, with a Danish amputee able to tell the strength of his grasp, along with the shape and consistency of objects he picked up. The hand, developed by teams at EPFL in Switzerland and SSSA in Italy, is wired into nerves in the wearer's upper arm, with stress in the artificial tendons running through the fingers translated into electrical impulses delicate enough to be fed into the body.

Dennis Aabo Sørensen lost his left hand nine years ago in a firework accident, and became the first to try out the surgically-fitted bionic hand. Despite concerns that the remaining nerves in his arm might have degraded to the point that the technology would not work, the sensations fed in from the prosthetic apparently reawakened them.

"The sensory feedback was incredible, I could feel things that I hadn't been able to feel in over nine years" Sørensen said of the tests, in which he was given objects to pick up and manipulate while blindfolded and wearing earplugs.

Although the technology in the hand itself is new, the team also had to develop a new type of electrode to be fitted to Sørensen's arm. Dubbed transneural electrodes, they're capable of passing the weak electrical signals the hand produces into the nervous system.

While the process to surgically implant them took a full week, the electrodes had to be removed after a month due to clinical trial rules.

That's an artificial limitation, however, the researchers behind the system argue, suggesting that in fact they could safely remain operational for years before needing to be replaced. Unfortunately commercial versions are said to be "years away," not least because the electronics that accompany the system need to be shrunk down to a point where they're portable for the wearer.

VIA MedicalXpress