Free Press Journal

Bionic hand allows patient to feel objects in real time


London: Scientists have developed a revolutionary new prosthetic hand which allows the amputee to feel life-like sensations from their fingers.

Dennis Aabo Sorensen from Denmark is the first amputee in the world to feel sensory rich information – in real-time – with the prosthetic hand wired to nerves in his upper arm.

The 36 year-old man could grasp objects intuitively and identify what he was touching while blindfolded.

Nine years after an accident caused the loss of his left hand, Sorensen became the first amputee to feel – in real-time – with a sensory-enhanced prosthetic hand that was surgically wired to nerves in his upper arm.

Silvestro Micera and his team at EPFL (Switzerland) and SSSA (Italy) developed the revolutionary sensory feedback that allowed Sorensen to feel again while handling objects.

“The sensory feedback was incredible. I could feel things that I hadn’t been able to feel in over nine years,” said Sorensen.

In a laboratory setting wearing a blindfold and earplugs, Sorensen was able to detect how strongly he was grasping, as well as the shape and consistency of different objects he picked up with his prosthetic.

“When I held an object, I could feel if it was soft or hard, round or square,” he said.

Micera and his team enhanced the artificial hand with sensors that detect information about touch.
This was done by measuring the tension in artificial tendons that control finger movement and turning this measurement into an electrical current. But this electrical signal is too coarse to be understood by the nervous system.

Using computer algorithms, the scientists transformed the electrical signal into an impulse that sensory nerves can interpret.

The sense of touch was achieved by sending the digitally refined signal through wires into four electrodes that were surgically implanted into what remains of Sorensen’s upper arm nerves.

“This is the first time in neuroprosthetics that sensory feedback has been restored and used by an amputee in real-time to control an artificial limb,” said Micera.

“We were worried about reduced sensitivity in Dennis’ nerves since they hadn’t been used in over nine years,” said Stanisa Raspopovic, first author of the study.

These concerns faded away as the scientists successfully reactivated Sorensen’s sense of touch.

The study was published in the journal Science Translational Medicine. P