Bionic hand allows amputee to feel again

[Buster's Uncle]

Bionic hand allows amputee to feel again
Reuters
By Ben Hirschler  2 hours ago



LONDON (Reuters) - Dennis Aabo Sorensen lost his left hand when a firework rocket he was holding exploded during New Year's Eve celebrations 10 years ago, and he never expected to feel anything with the stump again.

But for a while last year he regained his sense of touch after being attached to a "feeling" bionic hand that allowed him to grasp and identify objects even when blindfolded.

The prototype device, which was wired to nerves in the 36-year-old Dane's left arm, blurs the boundary between body and machine and scientists hope it could one day revolutionize the lives of many amputees.

There is still work to be done in miniaturizing components and tidying away trailing cables that mean the robotic hand has so far only been used in the lab, but Sorensen said the European research team behind the project had got the basics right.

"It was a great experience. It's amazing to feel something you haven't been able to feel for so many years," he told Reuters in a telephone interview. "It was pretty close to having the same feeling as in my normal hand."

Details of his month-long use of the bionic hand, including results from a week of concentrated daily tests, were reported by researchers from Italy, Switzerland, Germany, Britain and Denmark in the journal Science Translational Medicine on Wednesday.

Alastair Ritchie, a bioengineering expert at the University of Nottingham, who was not involved in the research, said the device was a logical next step but more clinical trials were now needed to confirm the system's viability.

"It's very exciting preliminary data but it's a one-case study and we now need to see more cases," he said.

Despite notable advances with prosthetic limbs, current artificial hands fall down when it comes to providing sensory feedback - a key element in human dexterity.

In his everyday life Sorensen uses a commercial prosthetic hand that can detect muscle movement in his stump to open and close his hand, but provides no sense of touch and requires him to watch constantly to prevent objects being crushed.

The new so-called LifeHand 2 prosthesis is far more sophisticated in combining intra-nerve wiring, robotics and computer science to create life-like feeling.


IMPLANTED ELECTRODES

Ultra-thin electrodes the width of a human hair were surgically implanted into the ulnar and median nerves of Sorensen's arm before he was attached to the robotic hand, which is equipped with various artificial sensors.

These sensors measure the tension in man-made tendons on each finger to assess the force used to grasp different objects, while computer algorithms transform this information into an electrical signal that the nerves can interpret.

The result is real-time sensation, including a gradation in feelings that allowed Sorensen in tests to detect both shape and consistency. In a series of experiments, he was able to recognize the basic shapes of objects, such as the cylinder of a bottle, and also feel differences in the stiffness between a mandarin orange and a baseball.

It is a big advance on an initial LifeHand 1 device unveiled in 2009, which was less refined and was not implanted on the patient but only connected through electrodes.

There is still a need for further work, however, in order for the new hand to differentiate between more detailed textures, as well as between hot and cold.

Silvestro Micera, an engineer at the Ecole Polytechnique Federale de Lausanne and the Cuola Superiore Sant'Anna in Pisa, said the challenge now was to ensure the system could remain implanted on multiple patients for "many months".

"Our final goal is to have this in clinical practice in five, six or seven years time - but the next step is to show in two to three years that this can work long term not just in one patient but in several patients," he said.

Assuming further clinical trials go well, the research team is likely eventually to bring in a commercial partner, although Micera said this was not on the cards just yet.

One big unknown is cost. The high-tech device will not be cheap but Micera said the surgery to implant the electrodes was relatively straightforward, which should limit hospital bills.


http://news.yahoo.com/bionic-hand-allows-amputee-feel-again-190742826.html

[Buster's Uncle]

Man Gets First Prosthetic Hand That Can Feel
LiveScience.com
By Tanya Lewis, Staff Writer  1 hour ago



The first prosthetic limb to give wearers sensory feedback has been described as "amazing" by an amputee who has just tested the device for the first time. The prototype hand is being developed by researchers in Switzerland and Italy



Nine years ago, Dennis Aabo Sørensen severely wounded his left arm in a fireworks accident, and had to have it amputated. Now, a bionic hand has restored his ability to feel, the first time this has ever been done.

Researchers embedded electrodes in Sørensen's arm, and touch sensors in a prosthetic hand to stimulate his remaining nerves. With the hand, Sørensen was able to recognize different objects by their feel, and grasp them appropriately, according to the study detailed online today (Feb. 5) in the journal Science Translational Medicine.

"I could feel things that I hadn't been able to feel in over nine years," Sørensen, who lives in Denmark, said in a statement.

So far, Sørensen is the only person to test the prosthesis, and he's had it for only a short time, but if proven to work over the long term in more people, the system could vastly improve the function of current prosthetic limbs and the quality of life for their users.


Restoring touch

The ability to feel is critical for the dexterity humans need to perform basic tasks with their hands. Tactile information tells a person how much force to use when grasping objects as rigid as a coffee mug or as delicate as a grape.



Amputee Dennis Aabo Sørensen wearing sensory feedback enabled prosthesis in Rome, March 2013.


"Without sensory feedback from our hands, we would have difficulties performing even the most basic activities of daily living," said Sliman Bensmaia, a neuroscientist at the University of Chicago, who was not involved in the research.

Many researchers are developing prosthetic systems aimed at restoring people's ability to control their arms or legs after amputation, spinal cord injury or disease. And increasingly, scientists are also working on incorporating touch-sensitive feedback. The new study is the first to demonstrate such feedback successfully in a human patient.

Silvestro Micera, a neural engineer at the Scuola Superiore Sant'Anna in Italy and the Swiss Federal Institute of Technology Lausanne in Switzerland, led the team that developed the feeling bionic hand. Micera and his team connected touch sensors in the artificial hand to electrodes surgically embedded in the remains of nerves in Sørensen's upper arm. Computer algorithms converted the signals from the sensors into a form the nerves could detect.

In a month-long clinical trial, Sørensen tested the hand, sometimes wearing a blindfold and earplugs so he could rely only on his sense of touch when using the hand. Sørensen was able to control how forcefully he grasped objects, and feel their shape and stiffness. He could tell the differences among hard, medium and soft objects, and identify the shapes of specific objects such as a cylindrical bottle or round baseball.

Sørensen told researchers that the artificial sense of touch was similar to the natural feeling he experienced in his other hand.


Better prostheses

In contrast with previous approaches to replace a lost sense of touch by, for example, vibrating the skin, the new approach provides "anatomically appropriate feedback," researchers said.

"By directly stimulating the nerves, it's possible that you can appropriately restore that sensory feedback," said Levi Hargrove, an electrical engineer at the Rehabilitation Institute of Chicago, who was not involved in the research.

Both Hargrove and Bensmaia noted that the study is preliminary, because it involved only a single person. Furthermore, in order to be a safe and useful device, the system would need to be fully implantable under the skin, and would need to keep working over a long time, they said.

Although it will probably be years before a system like the one Micera and colleagues developed is ready for clinical use, it is "certainly a major step in the right direction," Hargrove told Live Science.


http://news.yahoo.com/man-gets-first-prosthetic-hand-feel-202300302.html