Bionic hand allows amputee to feel with prosthetic fingers

European researchers created a bionic hand that gave an amputee a sense of touch through prosthetic fingers for the first time, it was reported this week. The experiment is part of a growing body of research that aims to develop advanced, lifelike prosthetics.

The experiment with LifeHand 2 lasted only a week, but it let Dennis Aabo Sorensen, 36, of Aalborg, Denmark, feel that different objects — a bottle, a baseball, some cotton, a mandarin orange — were hard or soft, slim or round, and intuitively adjust his grip.

"It was just amazing," said Sorensen, who lost his left hand in a fireworks accident and volunteered to pilot-test the bulky prototype. "It was the closest I have had to feeling like a normal hand."

This isn't the first time researchers have tried to give a sense of touch to artificial hands; a few other pilot projects have been reported in the U.S. and Europe. This latest effort, however, by Swiss and Italian researchers, is among the most advanced.

A report of their findings, published in the journal Science Translational Medicine on Wednesday, explains just how the prosthesis worked.

First, doctors at Rome's Gemelli Hospital implanted tiny electrodes, about the width of a human hair, inside two nerves — the ulnar and median nerves — in the stump of Sorensen's arm.

Those nerves would normally allow for certain sensations in a hand. When researchers zapped them with a weak electrical signal, Sorensen said it felt as if his missing fingers were moving, showing the nerves could still relay information.

Meanwhile, the team put sensors on two fingers of a robotic hand to detect information about what the artificial fingers touched.

For one week, cords snaked from a bandage on Sorensen's arm to the artificial hand, and the electrodes zapped the nerves in proportion to what the sensors detected, allowing him to respond to feeling in real time.

To be sure that Sorensen used touch, and didn't cheat by looking or by hearing telltale sounds, he wore a blindfold and headphones as researchers handed him different objects to touch.

"It was interesting to see how fast he was able to master this," engineer Silvestro Micera of Switzerland's Ecole Polytechnique Federale de Lausanne, who led the research team, told The Associated Press. "He was able to use this information immediately in a quite sophisticated way."

Still, the team says it will take years of additional research and development before an artificial hand that feels is available to the public that needs prosthetics. The team needs to prove that the nerve implants it used can last. For safety reasons, Sorensen's were surgically removed from his arm after the experiment was over.

The researchers also hope to improve the device by making it possible for users to differentiate between more finely detailed textures, as well as between hot and cold.

Al Jazeera and wire services