The world’s most advanced bionic hand

 

---

NEBIAS

A prosthetic hand, which provides a sense of touch acute enough to handle an egg, has been completed and is now exploited by the NEBIAS project after 10 years of EU-funded research. The world's most advanced bionic hand was tested with the help of amputee Dennis Aabo Sørensen who was able to grasp objects intuitively and identify what he was touching, while blindfolded.

Researchers have created a new neural interface to provide sensory information from an artificial hand to the brain. This interface is able to link the patient's nervous system with the artificial sensors, embedded in the prosthesis, enabling the user to control complex hand and finger movements.

Mr Sørensen, whose hand was amputated ten years ago, has been participating in the project's experiments, 'They gave me a baseball to hold and for the first time in a decade I could feel I was holding something round in my prosthetic hand.'

To make it possible for Mr Sørensen to feel the shape of the object he was holding, the researchers first had to develop a selective, implantable neuro-interface. 'Selective means, for example, that when I'm talking to you in a crowd, I'm not talking to a guy sitting close to you. In other words, the electrodes have an interface with some areas of the nerves and not with others close by,' explains project coordinator Dr Silvestro Micera . Micera and his team enhanced the artificial hand with sensors that detect information about touch, which is sent in real time to the patient, allowing for the natural control of the hand.

With the prototype passing its initial tests with flying colours, the next stage is to identify two or three people to test the prosthesis over some years, with all the elements being portable, wearable or implanted. If that works, in five or six years from now the final stage would be a large-scale clinical trial to establish if the prosthesis can be used widely. Dr Micera firmly believes the prosthesis will be available in ten years time.

Necessity of long-term funding

NEBIAS is a continuation of intensive multi-disciplinary research in this field which started many years ago with the CYBERHAND  (Future and Emerging Technologies) (FET) FP5 Project (2002-2005). While CYBERHAND was able to demonstrate a mechanical hand, the task of direct interfacing to the nervous system to enable natural control proved to be beyond the project's reach. Efforts to connect robotic artefacts to the nervous system were pursued notably under FP6 and FP7, with successful testing of a prototype electrode without sensory feedback and investigation on how electrodes could be implanted into a patient's nerve. The sensory feedback challenge was overcome only recently, and NEBIAS, also an FET funded project, is now fully exploiting the prosthesis and further developing the technology to bionic arms.

Building on the results of successive projects allows to overcome the various challenges and to refine the technology, resulting in ground breaking innovation that may well enhance the lives of amputees across Europe and beyond.

Innovation through collaboration

This multi-disciplinary research brought together researchers from materials, computer and neuro-sciences, biomedical microtechnology and electronic engineering. Over these different EU funded projects, scientists from 29 different institutions, involving 7 EU countries (and even a participation from USA) worked together with just one goal -- to make a prosthetic hand that can enable natural sensation and motion.

'This is one of the things I love about the EU,' says Dr Micera. 'These transnational projects are amazing. You can draw on a pool of over 500 million inhabitants to find the best researchers in different fields.'

NEBIAS, also, was launched at the start of November 2013 and will run for four years. It receives EUR 3.4 million from the European Commission's 7th Framework Programme .

---

Story Source:

The above story is based on materials provided by European Commission, CORDIS. Note: Materials may be edited for content and length.

---

 

Mind-controlled prosthetic arms that work in daily life are now a reality

 

---

For the first time, robotic prostheses controlled via implanted neuromuscular interfaces have become a clinical reality.

For the first time, robotic prostheses controlled via implanted neuromuscular interfaces have become a clinical reality. A novel osseointegrated (bone-anchored) implant system gives patients new opportunities in their daily life and professional activities.

In January 2013 a Swedish arm amputee was the first person in the world to receive a prosthesis with a direct connection to bone, nerves and muscles. An article about this achievement and its long-term stability will now be published in the Science Translational Medicine journal.

"Going beyond the lab to allow the patient to face real-world challenges is the main contribution of this work," says Max Ortiz Catalan, research scientist at Chalmers University of Technology and leading author of the publication.

"We have used osseointegration to create a long-term stable fusion between man and machine, where we have integrated them at different levels. The artificial arm is directly attached to the skeleton, thus providing mechanical stability. Then the human's biological control system, that is nerves and muscles, is also interfaced to the machine's control system via neuromuscular electrodes. This creates an intimate union between the body and the machine; between biology and mechatronics."

The direct skeletal attachment is created by what is known as osseointegration, a technology in limb prostheses pioneered by associate professor Rickard Brånemark and his colleagues at Sahlgrenska University Hospital. Rickard Brånemark led the surgical implantation and collaborated closely with Max Ortiz Catalan and Professor Bo Håkansson at Chalmers University of Technology on this project.

The patient's arm was amputated over ten years ago. Before the surgery, his prosthesis was controlled via electrodes placed over the skin. Robotic prostheses can be very advanced, but such a control system makes them unreliable and limits their functionality, and patients commonly reject them as a result.

Now, the patient has been given a control system that is directly connected to his own. He has a physically challenging job as a truck driver in northern Sweden, and since the surgery he has experienced that he can cope with all the situations he faces; everything from clamping his trailer load and operating machinery, to unpacking eggs and tying his children's skates, regardless of the environmental conditions (read more about the benefits of the new technology below).

The patient is also one of the first in the world to take part in an effort to achieve long-term sensation via the prosthesis. Because the implant is a bidirectional interface, it can also be used to send signals in the opposite direction -- from the prosthetic arm to the brain. This is the researchers' next step, to clinically implement their findings on sensory feedback.

"Reliable communication between the prosthesis and the body has been the missing link for the clinical implementation of neural control and sensory feedback, and this is now in place," says Max Ortiz Catalan. "So far we have shown that the patient has a long-term stable ability to perceive touch in different locations in the missing hand. Intuitive sensory feedback and control are crucial for interacting with the environment, for example to reliably hold an object despite disturbances or uncertainty. Today, no patient walks around with a prosthesis that provides such information, but we are working towards changing that in the very short term."

The researchers plan to treat more patients with the novel technology later this year.

"We see this technology as an important step towards more natural control of artificial limbs," says Max Ortiz Catalan. "It is the missing link for allowing sophisticated neural interfaces to control sophisticated prostheses. So far, this has only been possible in short experiments within controlled environments."

More about: How the technology works

The new technology is based on the OPRA treatment (osseointegrated prosthesis for the rehabilitation of amputees), where a titanium implant is surgically inserted into the bone and becomes fixated to it by a process known as osseointegration (Osseo = bone). A percutaneous component (abutment) is then attached to the titanium implant to serve as a metallic bone extension, where the prosthesis is then fixated. Electrodes are implanted in nerves and muscles as the interfaces to the biological control system. These electrodes record signals which are transmitted via the osseointegrated implant to the prostheses, where the signals are finally decoded and translated into motions.

More about: Benefits of the new technology, compared to socket prostheses

Direct skeletal attachment by osseointegration means:

• Increased range of motion since there are no physical limitations by the socket -- the patient can move the remaining joints freely
• Elimination of sores and pain caused by the constant pressure from the socket
• Stable and easy attachment/detachment
• Increased sensory feedback due to the direct transmission of forces and vibrations to the bone (osseoperception)
• The prosthesis can be worn all day, every day
• No socket adjustments required (there is no socket)

Implanting electrodes in nerves and muscles means that:

• Due to the intimate connection, the patients can control the prosthesis with less effort and more precisely, and can thus handle smaller and more delicate items.
• The close proximity between source and electrode also prevents activity from other muscles from interfering (cross-talk), so that the patient can move the arm to any position and still maintain control of the prosthesis.
• More motor signals can be obtained from muscles and nerves, so that more movements can be intuitively controlled in the prosthesis.
• After the first fitting of the controller, little or no recalibration is required because there is no need to reposition the electrodes on every occasion the prosthesis is worn (as opposed to superficial electrodes).
• Since the electrodes are implanted rather than placed over the skin, control is not affected by environmental conditions (cold and heat) that change the skin state, or by limb motions that displace the skin over the muscles. The control is also resilient to electromagnetic interference (noise from other electric devices or power lines) as the electrodes are shielded by the body itself.
• Electrodes in the nerves can be used to send signals to the brain as sensations coming from the prostheses.

Amputees discern familiar sensations across prosthetic hand

 

---

Medical researchers are helping restore the sense of touch in amputees.

Even before he lost his right hand to an industrial accident 4 years ago, Igor Spetic had family open his medicine bottles. Cotton balls give him goose bumps.

Now, blindfolded during an experiment, he feels his arm hairs rise when a researcher brushes the back of his prosthetic hand with a cotton ball.

Spetic, of course, can't feel the ball. But patterns of electric signals are sent by a computer into nerves in his arm and to his brain, which tells him different. "I knew immediately it was cotton," he said.

That's one of several types of sensation Spetic, of Madison, Ohio, can feel with the prosthetic system being developed by Case Western Reserve University and the Louis Stokes Cleveland Veterans Affairs Medical Center.

Spetic was excited just to "feel" again, and quickly received an unexpected benefit. The phantom pain he'd suffered, which he's described as a vice crushing his closed fist, subsided almost completely. A second patient, who had less phantom pain after losing his right hand and much of his forearm in an accident, said his, too, is nearly gone.

Despite having phantom pain, both men said that the first time they were connected to the system and received the electrical stimulation, was the first time they'd felt their hands since their accidents. In the ensuing months, they began feeling sensations that were familiar and were able to control their prosthetic hands with more -- well -- dexterity.

To watch a video of the research, click here: http://youtu.be/l7jht5vvzR4.

"The sense of touch is one of the ways we interact with objects around us," said Dustin Tyler, an associate professor of biomedical engineering at Case Western Reserve and director of the research. "Our goal is not just to restore function, but to build a reconnection to the world. This is long-lasting, chronic restoration of sensation over multiple points across the hand."

"The work reactivates areas of the brain that produce the sense of touch, said Tyler, who is also associate director of the Advanced Platform Technology Center at the Cleveland VA. "When the hand is lost, the inputs that switched on these areas were lost."

How the system works and the results will be published online in the journal Science Translational Medicine Oct. 8.

"The sense of touch actually gets better," said Keith Vonderhuevel, of Sidney, Ohio, who lost his hand in 2005 and had the system implanted in January 2013. "They change things on the computer to change the sensation.

"One time," he said, "it felt like water running across the back of my hand."

The system, which is limited to the lab at this point, uses electrical stimulation to give the sense of feeling. But there are key differences from other reported efforts.

First, the nerves that used to relay the sense of touch to the brain are stimulated by contact points on cuffs that encircle major nerve bundles in the arm, not by electrodes inserted through the protective nerve membranes.

Surgeons Michael W Keith, MD and J. Robert Anderson, MD, from Case Western Reserve School of Medicine and Cleveland VA, implanted three electrode cuffs in Spetic's forearm, enabling him to feel 19 distinct points; and two cuffs in Vonderhuevel's upper arm, enabling him to feel 16 distinct locations.

Second, when they began the study, the sensation Spetic felt when a sensor was touched was a tingle. To provide more natural sensations, the research team has developed algorithms that convert the input from sensors taped to a patient's hand into varying patterns and intensities of electrical signals. The sensors themselves aren't sophisticated enough to discern textures, they detect only pressure.

The different signal patterns, passed through the cuffs, are read as different stimuli by the brain. The scientists continue to fine-tune the patterns, and Spetic and Vonderhuevel appear to be becoming more attuned to them.

Third, the system has worked for 2 ½ years in Spetic and 1½ in Vonderhueval. Other research has reported sensation lasting one month and, in some cases, the ability to feel began to fade over weeks.

A blindfolded Vonderhuevel has held grapes or cherries in his prosthetic hand -- the signals enabling him to gauge how tightly he's squeezing -- and pulled out the stems.

"When the sensation's on, it's not too hard," he said. "When it's off, you make a lot of grape juice."

Different signal patterns interpreted as sandpaper, a smooth surface and a ridged surface enabled a blindfolded Spetic to discern each as they were applied to his hand. And when researchers touched two different locations with two different textures at the same time, he could discern the type and location of each.

Tyler believes that everyone creates a map of sensations from their life history that enables them to correlate an input to a given sensation.

"I don't presume the stimuli we're giving is hitting the spots on the map exactly, but they're familiar enough that the brain identifies what it is," he said.

Because of Vonderheuval's and Spetic's continuing progress, Tyler is hopeful the method can lead to a lifetime of use. He's optimistic his team can develop a system a patient could use at home, within five years.

In addition to hand prosthetics, Tyler believes the technology can be used to help those using prosthetic legs receive input from the ground and adjust to gravel or uneven surfaces. Beyond that, the neural interfacing and new stimulation techniques may be useful in controlling tremors, deep brain stimulation and more.