Össur Introduces First Mind-Controlled Bionic Prosthetic Lower Limbs For Amputees

Source of the Article: ossur.com, go to the website to see the video on the technology of these new prosthetics.

Össur Technology Adapts To User’s Subconscious, Intuitive Actions

Two amputees are the first people in the world able to control their Bionic prosthetic legs with their thoughts, thanks to tiny implanted myoelectric sensors (IMES) that have been surgically placed in their residual muscle tissue. The IMES, which was provided by the Alfred Mann Foundation, instantaneously triggers the desired movement, via a receiver located inside the prosthesis. This process occurs subconsciously, continuously and in real-time.

The announcement was made today by Jon Sigurdsson, President & CEO of Össur, the global innovator credited with creating the world’s first Bionic prostheses for amputees.

“Mind-controlled Bionic prosthetic legs are a remarkable clinical breakthrough in next-generation Bionic technology,” Sigurdsson said, speaking at the company’s Capital Markets Day in Copenhagen. “By adapting not only to the individual’s intentional movements but to intuitive actions, we are closer than ever to creating prosthetics that are truly integrated with their user.”

How Mind-Controlled Bionic Prosthetics Work

Össur’s commercially available Bionic prostheses are smart limbs capable of real-time learning and automatically adjusting to their user’s walking style (gait), speed and terrain. Walking with a Bionic prosthesis, however, still typically requires some conscious, intentional thought from the user.

According to Dr. Thorvaldur Ingvarsson, M.D., Ph.D, the orthopaedic surgeon who leads Össur’s research and development efforts and spearheaded the mind-controlled prosthetics project, movement in able-bodied individuals generally begins subconsciously, which triggers electrical impulses inside the body that catalyze the appropriate muscles into action. Össur’s new technology replicates that process in an amputee: that electronic impulse from the brain is received by an IMES that was surgically placed by Dr. Ingvarsson into muscles in the amputee’s residual limb.

“The technology allows the user’s experience with their prosthesis to become more intuitive and integrative,” Dr. Ingvarsson said. “The result is the instantaneous physical movement of the prosthesis however the amputee intended. They no longer need to think about their movements because their unconscious reflexes are automatically converted into myoelectric impulses that control their Bionic prosthesis.”

Promising First-In-Man Results

According to Dr. Ingvarsson, the mind-controlled technology works with all current commercially available Össur Bionic prostheses, including the company’s POWER KNEE, RHEO KNEE, PROPRIO FOOT and SYMBIONIC LEG.

Two amputees have participated in the company’s initial First-in-Man research. Both were implanted with the IMES and have been living with Össur’s mind-controlled Bionic prostheses for more than one year. Dr. Ingvarsson notes that feedback from both users has been very positive, and that clinical trials to further assess the technology will continue.

“As a global leader in prosthetics and orthopaedics, we at Össur never stop innovating. We are resolute in our commitment to expand the boundaries of possibility, so that we may help even more people enjoy a life without limitations,” Sigurdsson concluded.

About Össur

Össur (NASDAQ: OSSR) is a global leader in non-invasive orthopaedics that help people live a life without limitations. Its business is focused on improving people’s mobility through the delivery of innovative technologies within the fields of Prosthetic, Osteoarthritis and Injury Solutions.

A recognized “Technology Pioneer,” Össur invests significantly in research and product development—its award-winning designs ensuring a consistently strong position in the market. Successful patient and clinical outcomes are further empowered via Össur’s educational programs and business solutions. Headquartered in Iceland, Össur has major operations in the Americas, Europe and Asia, with additional distributors worldwide. www.ossur.com

New prosthetic foot to help tackle tough terrain

scientists have developed a more stable prosthetic foot which they say could make challenging terrain more manageable for people who have lost a lower

The new design has a kind of tripod foot that responds to rough terrain by actively shifting pressure between three different contact points.

“Prosthetic emulators allow us to try lots of different designs without the overhead of new hardware,” said Steven Collins, an at University in the US.

“Basically, we can try any kind of crazy design ideas we might have and see how people respond to them,” he said, without having to build each idea separately, an effort that can take months or years for each different design.

People with a amputation are five times more likely to fall in the course of a year, which may contribute to why they are also less socially engaged.

A better prosthetic limb could improve not just mobility but overall quality of life as well, according to the study published in the journal IEEE Transactions on

One area of particular interest is making prosthetic limbs that can better handle rough ground.

The solution, researchers thought, might be a tripod with a rear-facing heel and two forward-facing toes.

Outfitted with position sensors and motors, the foot could adjust its orientation to respond to varying terrain, much as someone with an intact foot could move their toes and flex their ankles to compensate while walking over rough ground.

Rather than building a prosthetic limb someone could test in the real world, the team, including graduate student and Alexandra Voloshina, instead built a basic tripod foot.

They then hooked it up to powerful off-board motors and computer systems that control how the foot responds as a user moves over all kinds of terrain.

The team can put their design focus on how the should function without having to worry about how to make the device lightweight and inexpensive at the same time.

The team reported results from work with a 60-year-old man who lost his below the knee due to diabetes.

The early results are promising — making the team hopeful they can take those results and turn them into more capable

“One of the things we are excited to do is translate what we find in the lab into lightweight and low power and therefore inexpensive devices that can be tested outside the lab,” Collins said.

“And if that goes well, we’d like to help make this a product that people can use in everyday life,” he said.

Source of the Article: business-standard.com

The magic touch: bringing sensory feedback to brain-controlled prosthetics

Researchers at the University of Chicago are leading a project to introduce the sense of touch to the latest brain-controlled prosthetic arms. Adding sensory feedback to already-complex neuroprosthetics is a towering task, but offers the chance to radically transform the lives of amputees and people living with paralysis.The future of prosthetics

Source of the Article: medicaldevice-network.com

Solar-powered synthetic skin could give robots a sense of touch and allow amputees to feel again

Synthetic skin capable of touch sensitivity could make smart prosthetic hands more useful for amputees

AI IS FUELING SMARTER PROSTHETICS THAN EVER BEFORE

By Andrea Powell

THE DISTANCE BETWEEN prosthetic and real is shrinking. Thanks to advances in batteries, brain-controlled robotics, and AI, today’s mechanical limbs can do everything from twist and point to grab and lift. And this isn’t just good news for amputees. “For something like bomb disposal, why not use a robotic arm?” says Justin Sanchez, manager of Darpa’s Revolutionizing Prosthetics program. Well, that would certainly be handy.

Brain-Operated Arm

Capable of: Touching hands, reaching out
Mind-controlled limbs aren’t new, but University of Pittsburgh scientists are working on an arm that can feel. Wires link the arm and brain, so when pressure is applied, a signal alerts the sensory cortex.

Hand That Sees

Capable of: Looking for an opportunity
Researchers at Newcastle University have designed a hand with a tiny camera that snaps pics of objects in its view. Then an AI determines an action. Like, grasp that beer and raise it to my mouth.

The Linx

Capable of: Climbing every mountain
Unlike older lower-limb prosthetics, the Linx can tell when it’s sitting in a chair. At just under 6 pounds, it relies on seven sensors that collect data on activity and terrain, helping the leg adapt to new situations.

Bebionic

Capable of: Making rude gestures
It’s the only prosthetic hand with air-bubbled fingertips—great for typing and handling delicate objects (like eggs). And because individual motors power natural movements, wearers can flip the bird in an instant.

The Michelangelo

Capable of: Painting masterpieces
Whereas many prosthetics have a stiff thumb, Ottobock designed this model with a secondary drive unit in the fattest finger—making it opposable. So it’s easier to hold, say, a paintbrush. Big thumbs up!

The LUKE Arm

Capable of: Wielding lightsabers
Yep, LUKE as in Skywalker. The Life Under Kinetic Evolution arm is the first muscle- controlled prosthetic to be cleared by the FDA. With up to 10 motors in the arm, the Force is definitely with this one.

Source of the Article: Wired.com

BIONIC LIMBS ‘LEARN’ TO OPEN A BEER

By Eric Niller

INFINITE BIOMEDICAL TECHNOLOGIES

ANDREW RUBIN SITS with a Surface tablet, watching a white skeletal hand open and close on its screen. Rubin’s right hand was amputated a year ago, but he follows these motions with a special device fitted to his upper arm.

Electrodes on his arm connect to a box that records the patterns of nerve signals firing, allowing Rubin to train a prosthetic limb to act like a real hand. “When I think of closing a hand, it’s going to contract certain muscles in my forearm,” he says. “The software recognizes the patterns created when I flex or extend a hand that I do not have.”

The 49-year-old college professor from Washington, DC, drives several times a month to Infinite Biomedical Technologies, a Baltimore startup company that is using deep learning algorithms to recognize the signals in his upper arm that correspond with various hand movements.

Each year, more than 150,000 people have a limb amputated after an accident or for various medical reasons. Most people are then fitted with a prosthetic device that can recognize a limited number of signals to control a hand or foot, for example.

But Infinite and another firm are taking advantage of better signal processing, pattern recognition software and other engineering advances to build new prosthetic controllers that might give Rubin and others an easier life. The key is boosting the amount of data the prosthetic arm can receive, and helping it interpret that information. “The goal for most patients is to get more than two functions, say open or close, or a wrist turn. Pattern recognition allows us to do that,” says Rahul Kaliki, CEO of Infinite. “We are now capturing more activity across the limb.”

Kaliki’s team of 14 employees are building the electronics that go inside other companies’ prosthetic arms. Infinite’s electronic control system, called Sense, records data from up to eight electrodes on his upper arm. Through many hours of training on the company’s tablet app, the device can detect the intent encoded in Rubin’s nerve signals when he moves his upper arm in a certain way. Sense then instructs his prosthetic hand to assume the appropriate grip.

Last Friday, Infinite’s Kaliki received notice from FDA officials that Sense had been approved for sale in the United States. Kaliki says he expects to begin installing them in prosthetic limbs by the end of November. In 2017, FDA officials approved a similar system by Chicago-based Coapt. Today more than 400 people are using the system at home, according to CEO Blair Lock.

COAPT

Lock started as an engineer 13 years ago at the Rehabilitation Institute of Chicago, an affiliate of Northwestern University. He worked with surgeons who were repairing nerve damage in amputee patients. Over time, he realized that building better prosthetics would be easier if he could figure out a way to pick up better signals from the body, he says. “What’s new is providing a much more natural, more intuitive method of control using [bio-electronic] signals,” Lock says.

In earlier versions of prosthetic devices, electrodes recorded signal strengths “but it was like listening to an orchestra and only knowing how loud the instruments are playing,” Lock says. “It was a significant effort to learn the content and fidelity of the signals.” The Coapt system works inside an amputee’s prosthetic hand and costs about $10,000 to $15,000, depending on the amount of customization needed. Artificial limbs can costs anywhere from $10,000 to $150,000, according to Lock.

Nicole Kelly got a new prosthetic device with the Coapt control system about a year ago. Now the 28-year-old Chicagoan can grind fresh pepper into her food and hold playing cards with friends. She can also open a beer.

“For many things, it wasn’t that I couldn’t do them before, but suddenly I can do them much easier,” says Kelly, who was born without her lower left arm.nHer prosthetic “is not my body, and it’s not 100 percent natural,” she said. “There’s a learning curve of my body communicating with this technology. Even the process of the best way to hold the salt and pepper shakers, I am essentially doing it for the first time.”

Source of the Article: https://www.wired.com/story/bionic-limbs-learn-to-open-a-beer/

DOCTORS WIRED A PROSTHETIC HAND DIRECTLY INTO A WOMAN’S NERVES

JON CHRISTIAN__FILED UNDER: ENHANCED HUMANS
VICTOR TANGERMANN

Sans Hand

In a world first, doctors in Sweden say they’ve wired a prosthetic hand directly into a woman’s nervesallowing her to move its fingers with her mind and even feel tactile sensations.

The hand is an enormous step up from existing prostheses, which often rely on electrodes placed on the outside of the skin — and it could herald a future in which robotic devices interface seamlessly with our bodies.

Nerve Case

Researchers at Chalmers University of Technology and biotech firm Integrum AB created the prosthetic hand as part of DeTOP, an ambitious European research program on prosthetic limbs.

Surgeons anchored the hand to the woman’s forearm bones using titanium implants. They connected an array of 16 electrodes directly to her nerves and muscles, allowing her to control the hand with her mind — and, according to photos, use it to tie shoelaces and type on a laptop computer.

“The breakthrough of our technology consists on enabling patients to use implanted neuromuscular interfaces to control their prosthesis while perceiving sensations where it matters for them, in their daily life,” Chalmers researcher Ortiz Catalan said in a press release.

Virtual Light

Electronics wired straight into a human nervous system allow for mind-bending new ways to interact with technology. A video released by the Swedish researchers even shows the woman using the implant to flex a virtual hand on a computer screen — before the actual physical hand was installed.

For decades, cyborg limbs like those depicted in “Star Wars” or “Neuromancer” seemed relegated to the realm of science fiction. New research shows that they’re already here — just not yet widely available.

Source of the Article: https://futurism.com/the-byte/prosthetic-hand-womans-nerves

Low-cost prosthetic foot mimics natural walking

New design can be tuned to an individual’s body weight and size.

Jennifer Chu | MIT News Office

Prosthetic limb technology has advanced by leaps and bounds, giving amputees a range of bionic options, including artificial knees controlled by microchips, sensor-laden feet driven by artificial intelligence, and robotic hands that a user can manipulate with her mind. But such high-tech designs can cost tens of thousands of dollars, making them unattainable for many amputees, particularly in developing countries.

Now MIT engineers have developed a simple, low-cost, passive prosthetic foot that they can tailor to an individual. Given a user’s body weight and size, the researchers can tune the shape and stiffness of the prosthetic foot, such that the user’s walk is similar to an able-bodied gait. They estimate that the foot, if manufactured on a wide scale, could cost an order of magnitude less than existing products.

The custom-designed prostheses are based on a design framework developed by the researchers, which provides a quantitative way to predict a user’s biomechanical performance, or walking behavior, based on the mechanical design of the prosthetic foot.

“[Walking] is something so core to us as humans, and for this segment of the population who have a lower-limb amputation, there’s just no theory for us to say, ‘here’s exactly how we should design the stiffness and geometry of a foot for you, in order for you to walk as you desire,’” says Amos Winter, associate professor of mechanical engineering at MIT. “Now we can do that. And that’s super powerful.”

Winter and former graduate student Kathryn Olesnavage report details of this framework in IEEE’s Transactions on Neural Systems and Rehabilitation. They have published their results on their new prosthetic foot in the ASME Journal of Mechanical Design, with graduate student Victor Prost and research engineer William Brett Johnson.

Following the gait

In 2012, soon after Winter joined the MIT faculty, he was approached by Jaipur Foot, a manufacturer of artificial limbs based in Jaipur, India. The organization manufactures a passive prosthetic foot, geared toward amputees in developing countries, and donates more than 28,000 models each year to users in India and elsewhere.

“They’ve been making this foot for over 40 years, and it’s rugged, so farmers can use it barefoot outdoors, and it’s relatively life-like, so if people go in a mosque and want to pray barefoot, they’re likely to not be stigmatized,” Winter says. “But it’s quite heavy, and the internal structure is made all by hand, which creates a big variation in product quality.”

The organization asked Winter whether he could design a better, lighter foot that could be mass-produced at low cost.

“At that point, we started asking ourselves, ‘how should we design this foot as engineers? How should we predict the performance, given the foot’s stiffness and mechanical design and geometry? How should we tune all that to get a person to walk the way we want them to walk?’” Winter recalls.

The team, led by Olesnavage, first looked for a way to quantitatively relate a prosthesis’ mechanical characteristics to a user’s walking performance — a fundamental relationship that had never before been fully codified.

While many developers of prosthetic feet have focused on replicating the movements of able-bodied feet and ankles, Winter’s team took a different approach, based on their realization that amputees who have lost a limb below the knee can’t feel what a prosthetic foot does.

“One of the critical insights we had was that, to a user, the foot is just kind of like a black box — it’s not connected to their nervous system, and they’re not interacting with the foot intimately,” Winter says.

Instead of designing a prosthetic foot to replicate the motions of an able-bodied foot, he and Olesnavage looked to design a prosthetic foot that would produce lower-leg motions similar to those of an able-bodied person’s lower leg as they walk.

“This really opened up the design space for us,” Winter says. “We can potentially drastically change the foot, so long as we make the the lower leg do what we want it to do, in terms of kinematics and loading, because that’s what a user perceives.”

With the lower leg in mind, the team looked for ways to relate how the mechanics of the foot relate to how the lower leg moves while the foot is in contact with the ground. To do this, the researchers consulted an existing dataset comprising measurements of steps taken by an able-bodied walker with a given body size and weight. With each step, previous researchers had recorded the ground reaction forces and the changing center of pressure experienced by a walker’s foot as it rocked from heel to toe, along with the position and trajectory of the lower leg.

Winter and his colleagues developed a mathematical model of a simple, passive prosthetic foot, which describes the stiffness, possible motion, and shape of the foot. They plugged into the model the ground reaction forces from the dataset, which they could sum up to predict how a user’s lower leg would translate through a single step.

With their model, they then tuned the stiffness and geometry of the simulated prosthetic foot to produce a lower-leg trajectory that was close to the able-bodied swing — a measure they consider to be a minimal “lower leg trajectory error.”

“Ideally, we would tune the stiffness and geometry of the foot perfectly so we exactly replicate the motion of the lower leg,” Winter says. “Overall, we saw that we can get pretty darn close to able-bodied motion and loading, with a passive structure.”

Evolving on a curve

The team then sought to identify an ideal shape for a single-part prosthetic foot that would be simple and affordable to manufacture, while still producing a leg trajectory very similar to that of able-bodied walkers.

To pinpoint an ideal foot shape, the group ran a “genetic algorithm” — a common technique used to weed out unfavorable options, in search of the most optimal designs.

“Just like a population of animals, we made a population of feet, all with different variables to make different curve shapes,” Winter says. “We loaded them into simulation and calculated their lower leg trajectory error. The ones that had a high error, we killed off.”

Those that had a lower error, the researchers further mixed and matched with other shapes, to evolve the population toward an ideal shape, with the lowest possible lower leg trajectory error. The team used a wide Bezier curve to describe the shape of the foot using only a few select variables, which were easy to vary in the genetic algorithm. The resulting foot shape looked similar to the side-view of a toboggan.

Olesnavage and Winter figured that, by tuning the stiffness and shape of this Bezier curve to a person’s body weight and size, the team should be able to produce a prosthetic foot that generates leg motions similar to able-bodied walking. To test this idea, the researchers produced several feet for volunteers in India. The prostheses were made from machined nylon, a material chosen for its energy-storage capability.

“What’s cool is, this behaves nothing like an able-bodied foot — there’s no ankle or metatarsal joint — it’s just one big structure, and all we care about is how the lower leg is moving through space,” Winter says. “Most of the testing was done indoors, but one guy ran outside, he liked it so much. It puts a spring in your step.”

Going forward, the team has partnered with Vibram, an Italian company that manufactures rubber outsoles — flexible hiking boots and running shoes that look like feet. The company is designing a life-like covering for the team’s prosthesis, that will also give the foot some traction over muddy or slippery surfaces. The researchers plan to test the prosthetics and coverings on volunteers in India this spring.

Winter says the simple prosthetic foot design can also be a much more affordable and durable option for populations such as soldiers who want to return to active duty or veterans who want to live an active lifestyle.

“A common passive foot in the U.S. market will cost $1,000 to $10,000, made out of carbon fiber. Imagine you go to your prosthetist, they take a few measurements, they send them back to us, and we send back to you a custom-designed nylon foot for a few hundred bucks. This model is potentially game-changing for the industry, because we can fully quantify the foot and tune it for individuals, and use cheaper materials.”

This research was funded, in part, by the MIT Tata Center for Technology and Design.

Source of Article: http://news.mit.edu/2018/low-cost-prosthetic-foot-mimics-natural-walking-0627

BIOMEDICAL ENGINEERING BRINGING A HUMAN TOUCH TO MODERN PROSTHETICS

‘Electronic skin’ allows user to experience a sense of touch and pain; ‘After many years, I felt my hand, as if a hollow shell got filled with life again,’ amputee volunteer says

Amputees often experience the sensation of a “phantom limb”—a feeling that a missing body part is still there.

That sensory illusion is closer to becoming a reality thanks to a team of engineers at Johns Hopkins University that has created an electronic skin. When layered on top of prosthetic hands, this e-dermis brings back a real sense of touch through the fingertips.

“After many years, I felt my hand, as if a hollow shell got filled with life again,” says the amputee who served as the team’s principal volunteer. (The research protocol used in the study does not allow identification of the amputee volunteers.)

Made of fabric and rubber laced with sensors to mimic nerve endings, e-dermis recreates a sense of touch as well as pain by sensing stimuli and relaying the impulses back to the peripheral nerves.

“We’ve made a sensor that goes over the fingertips of a prosthetic hand and acts like your own skin would,” says Luke Osborn, a graduate student in biomedical engineering. “It’s inspired by what is happening in human biology, with receptors for both touch and pain.

Luke Osborn interacts with prosthetic hand

Image caption:Luke Osborn interacts with a prosthetic hand sporting the e-dermis

IMAGE CREDIT: LARRY CANNER / HOMEWOOD PHOTOGRAPHY

“This is interesting and new,” Osborn adds, “because now we can have a prosthetic hand that is already on the market and fit it with an e-dermis that can tell the wearer whether he or she is picking up something that is round or whether it has sharp points.”

The work, published online in the journal Science Robotics, shows it’s possible to restore a range of natural, touch-based feelings to amputees who use prosthetic limbs. The ability to detect pain could be useful, for instance, not only in prosthetic hands but also in lower limb prostheses, alerting the user to potential damage to the device.

Human skin is made up of a complex network of receptors that relay a variety of sensations to the brain. This network provided a biological template for the research team, which includes members from the Johns Hopkins departments of Biomedical EngineeringElectrical and Computer Engineering, and Neurology, and from the Singapore Institute of Neurotechnology.

VIDEO: AMERICAN ACADEMY FOR THE ADVANCEMENT OF SCIENCE

Bringing a more human touch to modern prosthetic designs is critical, especially when it comes to incorporating the ability to feel pain, Osborn says.

“Pain is, of course, unpleasant, but it’s also an essential, protective sense of touch that is lacking in the prostheses that are currently available to amputees,” he says. “Advances in prosthesis designs and control mechanisms can aid an amputee’s ability to regain lost function, but they often lack meaningful, tactile feedback or perception.”

That’s where the e-dermis comes in, conveying information to the amputee by stimulating peripheral nerves in the arm, making the so-called phantom limb come to life. Inspired by human biology, the e-dermis enables its user to sense a continuous spectrum of tactile perceptions, from light touch to noxious or painful stimulus.

The e-dermis does this by electrically stimulating the amputee’s nerves in a non-invasive way, through the skin, says the paper’s senior author, Nitish Thakor, a professor of biomedical engineering and director of the Biomedical Instrumentation and Neuroengineering Laboratory at Johns Hopkins.

“For the first time, a prosthesis can provide a range of perceptions from fine touch to noxious to an amputee, making it more like a human hand,” says Thakor, co-founder of Infinite Biomedical Technologies, the Baltimore-based company that provided the prosthetic hardware used in the study.

THE TEAM FOCUSED ON DEVELOPING A SYSTEM CAPABLE OF DETECTING OBJECT CURVATURE (FOR TOUCH AND SHAPE PERCEPTION) AND SHARPNESS (FOR PAIN PERCEPTION).

The team created a “neuromorphic model” mimicking the touch and pain receptors of the human nervous system, allowing the e-dermis to electronically encode sensations just as the receptors in the skin would. Tracking brain activity via electroencephalography, or EEG, the team determined that the test subject was able to perceive these sensations in his phantom hand.

The researchers then connected the e-dermis output to the volunteer by using a noninvasive method known as transcutaneous electrical nerve stimulation, or TENS. In a pain-detection task the team determined that the test subject and the prosthesis were able to experience a natural, reflexive reaction to both pain while touching a pointed object and non-pain when touching a round object.

The e-dermis is not sensitive to temperature—for this study, the team focused on detecting object curvature (for touch and shape perception) and sharpness (for pain perception). The e-dermis technology could be used to make robotic systems more human, and it could also be used to expand or extend to astronaut gloves and space suits, Osborn says.

The researchers plan to further develop the technology and work to better understand how to provide meaningful sensory information to amputees in the hopes of making the system ready for widespread patient use.

Johns Hopkins is a pioneer in the field of upper limb dexterous prosthesis. More than a decade ago, the university’s Applied Physics Laboratory led the development of the advanced Modular Prosthetic Limb, which an amputee patient controls with the muscles and nerves that once controlled his or her real arm or hand.

Posted in Science+Technology

Source of article: https://hub.jhu.edu/2018/06/20/e-dermis-prosthetic-sense-of-touch/

New artificial nerves could transform prosthetics

Source of the Article: www.sciencemag.org

 

Prosthetics may soon take on a whole new feel. That’s because researchers have created a new type of artificial nerve that can sense touch, process information, and communicate with other nerves much like those in our own bodies do. Future versions could add sensors to track changes in texture, position, and different types of pressure, leading to potentially dramatic improvements in how people with artificial limbs—and someday robots—sense and interact with their environments.

“It’s a pretty nice advance,” says Robert Shepherd, an organic electronics expert at Cornell University. Not only are the soft, flexible, organic materials used to make the artificial nerve ideal for integrating with pliable human tissue, but they are also relatively cheap to manufacture in large arrays, Shepherd says.

Modern prosthetics are already impressive: Some allow amputees to control arm movement with just their thoughts; others have pressure sensors in the fingertips that help wearers control their grip without the need to constantly monitor progress with their eyes. But our natural sense of touch is far more complex, integrating thousands of sensors that track different types of pressure, such as soft and forceful touch, along with the ability to sense heat and changes in position. This vast amount of information is ferried by a network that passes signals through local clusters of nerves to the spinal cord and ultimately the brain. Only when the signals combine to become strong enough do they make it up the next link in the chain.

Now, researchers led by chemist Zhenan Bao at Stanford University in Palo Alto, California, have constructed an artificial sensory nerve that works in much the same way. Made of flexible organic components, the nerve consists of three parts. First, a series of dozens of sensors pick up on pressure cues. Pressing on one of these sensors causes an increase in voltage between two electrodes. This change is then picked up by a second device called a ring oscillator, which converts voltage changes into a string of electrical pulses. These pulses, and those from other pressure sensor/ring oscillator combos, are fed into a third device called a synaptic transistor, which sends out a series of electrical pulses in patterns that match those produced by biological neurons.

Bao and her colleagues used their setup to detect the motion of a small rod moving in different directions across their pressure sensors, as well as identify Braille characters. What’s more, they managed to connect their artificial neuron to a biological counterpart. The researchers detached a leg from a cockroach and inserted an electrode from the artificial neuron to a neuron in the roach leg; signals coming from the artificial neuron caused muscles in the leg to contract, they report today in Science.

Because organic electronics like this are inexpensive to make, the approach should allow scientists to integrate large numbers of artificial nerves that could pick up on multiple types of sensory information, Shepherd says. Such a system could provide far more sensory information to future prosthetics wearers, helping them better control their new appendages. It could also give future robots a greater ability to interact with their ever-changing environments—something vital for performing complex tasks, such as caring for the elderly.