Tag Archives: prosthetic

A high-tech prosthetic hand allows users to experience touch. Credit: University of Utah.

Scientists develop prosthetic hand that enables users to feel touch

A high-tech prosthetic hand allows users to experience touch. Credit: University of Utah.

A high-tech prosthetic hand allows users to experience touch. Credit: University of Utah.

An electrical accident 17 years ago claimed Keven Walgamott’s hand. Now, researchers at the University of Utah have fitted the man with an innovative prosthetic arm whose fingers not only move with his thoughts but are also capable of relaying sensations. Essentially, this is a prosthetic hand that feels. It’s so sensitive that Walgamott was able to hold an egg between his fingers without breaking it by squeezing it too hard.

The prosthetic hand that feels

The technology was developed by a team led by biomedical engineering associate professor Gregory Clark. The backbone of the prototype is the Utah Slanted Electrode Array (USEA), which is an interface between the prosthetic hand and the patient’s remaining sensory and motor nerves in the arms.

USEA consists of hundreds of electrodes that are surgically implanted next to the nerve fibers. The electrodes pick up the ‘chatter’ of nearby nerve fibers, forming a connection between the prosthesis and the nervous system.

The prosthetic — called “LUKE” after the prosthetic Luke Skywalker wore in Star Wars — was fitted to Walgamott in 2017. Since then, he has been training closely with the researchers at the University of Utah to perform extremely delicate tasks that would have been otherwise impossible using metal hooks or claws prosthetics.

“It almost put me to tears,” Walgamott said. “It was really amazing. I never thought I would be able to feel in that hand again.”

Scientists have been working on the LUKE arm for more than 15 years. It’s mostly made of metal motors and parts which control finely articulated fingers, along with an external battery that’s wired to a computer. Sensors cover the hand that sends signals to the nerves via the microelectrode array, mimicking the feeling you feel in your hand when picking up something.

Star Wars-inpired

One huge breakthrough in developing LUKE’s touch involved understanding and recreating how the brain interprets first touching something.

“Just providing sensation is a big deal, but the way you send that information is also critically important, and if you make it more biologically realistic, the brain will understand it better and the performance of this sensation will also be better,” said Clark.

Although the quality of touch that Walgamott can feel with his new prosthesis isn’t nearly as sensitive as a real hand, this is still a huge leap from nothing at all. With it, Walgamott can distinguish between touching something soft or hard, the kind of sensitivity that allows him to live a fuller life. For instance, the researchers claim that the man is now able to perform complex movements such as picking grapes or stuffing a pillow into its case.

For Walgamott, these training sessions have been incredibly emotional.

“One of the first things he wanted to do was put on his wedding ring. That’s hard to do with one hand,” says Clark. “It was very moving.”

Next, Clark and colleagues plan to improve the design of the prosthetic to make a mobile version. Right now, it can only be used in the lab where it has to be hooked up with all sorts of bulky machinery.

Clark hopes that in 2020 or 2021, three participants will be able to take their arms home, as long as they receive FDA approval.

It’ll take years, though, before such devices are commercially available. Nevertheless, it’s incredibly inspiring to see technology truly in service of the people.

Bioprosthetic ovary.

Female mice birth and nurse healthy offspring after being grafted with prosthetic ovaries

A team of researchers from the Northwestern University Feinberg School of Medicine and McCormick School of Engineering has developed a process to create for fully-organic, 3D-printed ovarian bioprosthesis. Trials on mice showed that females implanted with the ovary could ovulate normally, even give birth to healthy pups and successfully nurse them, the team reports.

Bioprosthetic ovary.

Image credits Northwestern University.

The research stands out in regards to the prosthesis’ architecture and of the team’s choice of ‘ink’. They used gelatin, a hydrogel made from processed collagen, to create a scaffold-like structure which is safe to use in living organisms. Gelatin is a lot more resilient than other hydrogels, meaning the prosthetics can be made porous while staying hardy enough to be handled during surgery.

“We found a gelatin temperature that allows it to be self-supporting, not collapse, and lead to building multiple layers. No one else has been able to print gelatin with such well-defined and self-supported geometry,” said Ramille Shah, assistant professor of materials science and engineering at McCormick and of surgery at Feinberg.

Holesome prosthetics

That porosity is a critical element for a functioning ovarian replacement. The team was the first to show that the hormone-producing cells of the ovaries, called follicles, the same cells which surround and care for immature eggs/ova, have a much better chance of surviving in a scaffolding-like structure than on a solid platform.

Ovarian scaffolding structure.

Image credits M. Laronda et al., Nature Communications, 2017.

Creating the prosthetics is similar to building a house of logs, said Alexandra Rutz, co-lead author of the study and a former biomedical engineering graduate fellow in Shah’s Tissue Engineering and Additive Manufacturing (TEAM) lab at the Simpson Querrey Institute. You lay the logs at right angles to form the overall structure, and simply leave more space between them when you want a window or a door. Similarly, the printer lays down filament-like structures. By altering the distance between them as well as the angle between successive layers, the team can create any arrangement of pores of variable sizes.

They designed this prosthetic based on the structure of the “ovary skeleton”, and liken it to the scaffolding that surrounds buildings undergoing repairs or those still under construction. But unlike traditional scaffolding, it’s meant to be permanent. The prosthetic is meant to be implanted into a female, where it will promote and guide the development of new follicles, and then keep these cells and the developing eggs safe and happy to boost their effectiveness. Because the prosthetic is mostly open space, there’s enough room for blood vessels to grow and shuttle hormones and nutrients to and from the rest of the body. It also ensures there’s enough space for eggs (which are some of the largest single human cells at 0.12 millimeters) to mature in.

Printing for posterity

The bioprosthetic scaffolding should help restore fertility and normalize hormone production for women who risk infertility and hormone-associated developmental issues following childhood or adult cancer treatments. Some patients’ ovaries can partially or completely shut down following treatment and need to undergo hormone replacement therapies to maintain a normal developmental pattern — such as triggering puberty, for example. The prosthetics should offer an alternative long-term treatment for these patients, who didn’t have any alternative apart from ovarian transplants (usually from cadavers) address their condition until now.

“The purpose of this scaffold is to recapitulate how an ovary would function. We’re thinking big picture, meaning every stage of the girl’s life, so puberty through adulthood to a natural menopause,” said Monica Laronda, co-lead author of the paper.

Mice females who had their ovaries replaced with the scaffolding had healthy pups and showed normal nursing behaviors, suggesting a normal hormone balance. Successful creation of 3D-printed implants which can replace complex soft tissue could significantly aid future research into soft tissue regenerative biomedicine, the team notes.

The full paper “A bioprosthetic ovary created using 3D printed microporous scaffolds restores ovarian function in sterilized mice” has been published in the journal Nature Communications.

Company reveals 3D printed superhero prosthetics for kids

Sometimes, it’s not just about the functionality of a prosthetic, but the hope and morale it brings. With this in mind, Open Bionics, a startup working to provide affordable, 3D printed prosthetic hands for amputees has revealed prosthetic arms for kids inspired from Iron Man, Frozen or Star Wars.

Based in Bristol, UK, Open Bionics first began its collaboration with Disney when it was selected for the 2015 Disney Accelerator program. The prosthetics they develop come at the relatively low cost of $500 and are fully robotic and responsive to the user’s movements. They were thrilled to have this opportunity of working with Disney, in making the world a better (or at the very least, a nicer) place.

“This is a once in a lifetime opportunity to get support and mentorship,” says Samantha Payne, COO of Open Bionics. However, according to Open Bionics CEO Joel Gibbard, pursuing one’s passion does not require the support of a multinational corporation. “If someone wants to get involved with something they’re interested in, the best way to do that is just to start doing it,” says Gibbard. “Follow tutorials, start making things, engage with communities. The more you do that, the better you’ll become and eventually you’ll get lucky like me and find yourself doing what you love for a living!”

To make things even better, their designs are fully open source, and their non-Disney hands can go as low as $100, weighing under 300 grams.

All images via Open Bionics.

Paralyzed man becomes the first person to feel physical sensations through a prosthetic hand directly connected to his brain

A 28-year old who has been paralyzed for more than a decade following a spinal cord injury has become the first person to be able to “feel” physical sensations, through a special prosthetic developed by DARPA – the Defense Advanced Research Projects Agency, a US agency responsible for the development of emerging technologies, mostly for military purposes. The prosthetic hand is connected directly to his brain, allowing him to feel sensations in it.

“We’ve completed the circuit,” said DARPA program manager Justin Sanchez. “Prosthetic limbs that can be controlled by thoughts are showing great promise, but without feedback from signals traveling back to the brain it can be difficult to achieve the level of control needed to perform precise movements. By wiring a sense of touch from a mechanical hand directly into the brain, this work shows the potential for seamless bio-technological restoration of near-natural function.”

This is not the actual prosthetic DARPA used. The volunteer’s identity has been kept secret for privacy reasons. Image via Tech Times.

Electrodes were placed into the volunteer’s cortex, and a special array was placed on his motor cortex, the part of the brain responsible for movements. Then, wires from his motor cortex were connected to a mechanical hand developed by the Applied Physics Laboratory (APL) at Johns Hopkins University. Firstly, this allowed him to move the hand with his thoughts – a remarkable achievement, but something which had already been done.

But then, DARPA breached new ground. They provided the volunteer with a sense of touch! The prosthetic hand contains a vast and sophisticated array of torque sensors that can detect when pressure is being applied, and can convert those physical sensations into electrical signals which are then passed on directly to the brain. In other words, they gave the patient a sense of touch in his 3rd, prosthetic arm.

The feeling, he reported, was as if his own hand was being touched. When blindfolded, the volunteer could determine which finger on the hand was touched with nearly 100% accuracy. Even when the team tried to trick him, he caught on to it.

“At one point, instead of pressing one finger, the team decided to press two without telling him,” said Sanchez, who oversees the Revolutionizing Prosthetics program. “He responded in jest asking whether somebody was trying to play a trick on him. That is when we knew that the feelings he was perceiving through the robotic hand were near-natural.”

Restoring memories

Image via io9

The restoration of sensation is one of several neurotechnology-based advances emerging from DARPA’s 18-month-old Biological Technologies Office, Sanchez said.

“DARPA’s investments in neurotechnologies are helping to open entirely new worlds of function and experience for individuals living with paralysis and have the potential to benefit people with similarly debilitating brain injuries or diseases,” he said.

This is tightly connected to another DARPA project, restoring memories (especially to soldiers and veterans).

“Traumatic brain injury (TBI) is a serious cause of disability in the United States. Diagnosed in more than 270,000 military service members since 2000 and affecting an estimated 1.7 million U.S. civilians each year, TBI frequently results in an impaired ability to retrieve memories formed prior to injury and a reduced capacity to form or retain new memories following injury,” their website reads.

The end goal of this project is to develop a wireless, fully implantable neural-interface medical device that would allow humans to retrieve memories currently inaccessible to them, which to me, is simply mind blowing. We’ve reached a stage where we can not only create prosthetics we can control with our hands, but we can also create sensations in them, and we can tap into how our brain accesses memories. These are truly remarkable times we are living in.

 

Three Austrian men become real-life Cyborgs

Bionic hands – artificial limbs controlled through thought power – they’re as awesome as they sound, and now they’re a much needed reality. Three Austrian men have become real-life cyborgs after having losing their hands to injury and then undergoing innovative surgery, receiving bionic hands.

The three Austrian men suffered injuries to the brachial plexus, a critical network of nerves which links the arm and shoulder to the spine and brain. Although a part of their hand was still there, it was pretty much useless.

“In effect, brachial plexus avulsion injuries represent an inner amputation, irreversibly separating the hand from neural control. Existing surgical techniques for such injuries are crude and ineffective and result in poor hand function,” explains Professor Oskar Aszmann, Director of the Christian Doppler Laboratory for Restoration of Extremity Function at the Medical University of Vienna

Three months ago, in a landmark surgery, all three of them underwent bionic reconstruction – their useless limb parts were replaced with artificial components. Today, for the first time in years, all three were able to accomplish everyday tasks such as picking up a ball, drinking water, cutting with a knife and opening their buttons using their bionic, thought-controlled hands.

“The decision to let go of his own hand is definitely not an easy one. Why? Because the patient still has a hand. But you must not forget that these patients have lived without hand function for about ten, 15 years and they know what it means to live without hands,” explained Professor Oskar Aszmann.

In order to do this, the surgical team transplanted nerves and muscles from their legs to their arms.

Image via BBC

 

While there have been many advancements in the field of smart prosthetics, this is still the first time this type of surgery has been done. The fact that it was done on three patients and was successful in all cases is extremely encouraging, but we still have to wait a while before assessing the long term impact.

“So far, bionic reconstruction has only been done in our centre in Vienna,” added Professor Aszmann, “However, there are no technical or surgical limitations that would prevent this procedure from being done in centres with similar expertise and resources.”

The problem when you try to integrate biological functions with mechanical functions is that in time, the cooperation tends to drop in time. Professor Simon Kay who carried out the UK’s first hand transplant, and Daniel Wilks from Leeds Teaching Hospitals NHS Trust, Leeds, UK believe this type of procedure will raise significant challenges in the future:

“The present findings—and others—are encouraging, because this approach provides additional neural inputs into prosthetic systems that otherwise would not exist. However, the final verdict will depend on long-term outcomes, which should include assessment of in what circumstances and for what proportion of their day patients wear and use their prostheses. Compliance declines with time for all prostheses, and motorised prostheses are heavy, need power, and are often noisy, as well as demanding skilled repair when damaged.”

Either way, no matter how you look at it, the fact that we are now able to create artificial limbs which we can control with our brains is absolutely spectacular.

The study detailing the procedure was published in The Lancet.

The video game-esque Exo prosthetic developed by New York based designer William Root. Credit: William Root

Meet the slickest, meanest 3-D prosthetis yet

The video game-esque Exo prosthetic developed by New York based designer William Root. Credit: William Root

The video game-esque Exo prosthetic developed by New York based designer William Root. Credit: William Root

Prosthetic limbs can cost tens of thousands of dollars onward, but thanks to 3-D printing many people can now recover part of their missing limbs for a fraction of the cost. Previously, we reported how a $42,000 prosthetic hand was replaced by 3D printed counterpart worth $50. Another prosthetic hand costs $10. Both models are open source and free to print by anyone at home. But a prosthesis shouldn’t necessarily be solely pragmatic, and  William Root, a recent graduate from the Pratt Institute in New York City, cared to demonstrate an alternate route. By combing biomechatronics and aesthetics, Root developed a prototype that’s a custom fit for each wearer, uses a minimal amount of top class materials and assures high mobility, all while looking as fit it came off a SciFi movie.

The model can be 3-D printed with  titanium or steel, making it lightweight and durable. Image: William Root

The model can be 3-D printed with titanium or steel, making it lightweight and durable. Image: William Root

“In my research it became clear to me that there is a lot wrong with how designers typically try to approach a prosthetic limb and how the industry goes about making prostheses,” says Root. “Prostheses are not aesthetically pleasing, extremely expensive, and difficult to produce.”

MIT’s FitSocket technology helps build prosthetics that suit a patient’s height, weight, and muscle mass. Illustration: MIT Mechatronics Lab

MIT’s FitSocket technology helps build prosthetics that suit a patient’s height, weight, and muscle mass. Illustration: MIT Mechatronics Lab

The road to building the Exo prosthetic first starts with modeling the wearer’s anatomy. A device developed at  MIT’s Biomechatronics lab called FitSocket uses an array of pressure sensors displaced in a circular pattern to determine the stiffness and softness of the remaining tissue. Using this pressure data, a 3D model with a near-perfect fit socket is made for maximum comfort and stability. The same data is then used to extrapolate a 3-D model of the actual prosthetic based on how the rest of the leg should have looked like. Stress analysis tools turn the model into fine meshes and carves the model until it “has the maximum strength for the least amount of material with the added benefit of looking really slick,” says Root.

The FitSocket. Image: William Root

The FitSocket. Image: William Root

Ultimately, the model is printed from sintered titanium powder or high-strength plastic. Durability, comfort and aesthetics.

“Prosthetic limbs are stigmatized because they are so inhuman; most aftermarket companies that try to address this problem attempt to create a realistic-looking leg, which crosses into the uncanny valley,” says Root.

“With prostheses you are essentially designing a person, their body already dictates the form,” he says. “Each leg needs to be as unique as its owner.”

Image: WILLIAM ROOT

Image: WILLIAM ROOT

Root says that the 3-D printed elements of his leg cost just $1,800, however the knee and ankle joints cost extra since these are high specialized components. According to Wired, Exo does not yet support a wearer’s full weight, but is in the process of gaining an approval from the FDA based on future, refined models. To pass the FDA strict guidelines, the Exo might both end up looking different and more expensive. Personally, I’m really excited about it and looking forward to seeing it work in the real world.

“With the Exo, the cost of the limb would be reduced almost to just the cost of printing it,” says Root. “As 3-D printing technology advances and becomes more mainstream those costs have nowhere to go but down.”

Dog born without front legs can walk thanks to 3D Printing

Unfortunately, Derby the husky cross wasn’t born like other dogs. While her back paws are normal and well developed, a deformity caused him to be born with small and very twisted forelegs. He couldn’t walk at all. But Derby caught a break when she was adopted by Tara Anderson, who works for a 3D printing company called 3D Systems. Tara teamed up with an animal orthotist, Derrick Campana, and together, the two 3D Printed prosthetic legs for Derby to use and walk on, as you can see below.

“We’re using a variety of 3D technologies, and that allows us to get in there and really modify the organic digital models quickly and easily, and start to do the sort of designs that Derrick wants us to do,” one of the team, Kevin Atkins from 3D systems says in the video above.

The approach was a total success, and Derby now runs over 5 km a days he’s much happier.

“This is what 3D printing is about,” Anderson told Jeff Parsons at The Mirror. “To be able to help anybody; a dog, person, whoever, to have a better life, there is no better thing to be involved in.”

In order to create the prosthetics, Derrick and Tara first scanned the husky’s front legs, and within hours, they built custom ‘arms’ for him. These arms also incorporate rubber treads to soften the impact when Derby is running, rigid spokes, and straps that hold them in place on his body.

This is not the first time 3D Printing has been used to help an animal walk. Just a few days ago we were telling you about a turtle who is able to walk thanks to a custom-built LEGO wheelchair. The technology is hitting the world, and hitting it hard… in a good way.

 

smart-skin

Time for the prosthetic skin: granting touch where its been lost

Brain-computer interfaces have helped prosthetics go a long, long way. ZME Science showed you a couple of such examples, like the case of a mechanical arm remotely controlled by a man using only using thoughts or the mind-blowing high-tech prosthetic by DARPA that empowered a veteran who had lost him limb to perform all sorts of complex tasks previously unimaginable for a prosthetic. The trend is to develop mechanical replacements that mimic the real limb as closely as possible, however, beyond their practical use our limbs are important for another important reason – sensing. South Korean researchers are at the very frontline of this line of research; they report a smart prosthetic skin instrumented with ultrathin, single crystalline ​silicon nanoribbon (SiNR) strain, pressure and temperature sensor arrays. This artificial skin can be stretched across a whole prosthetic and might one day complete the whole array of needs a prosthetic must meet: practicality, aestheticism and sensation.

Prosthetic touch

smart-skin

Credit: Seoul National University

In the paper’s abstract, the Seoul National University team acknowledges that while significant progress has been made  “understanding the neural circuits underlying mechanical and thermal sensation, replicating these capabilities in artificial skin and prosthetics remains challenging.” For instance, ZME Science reported last year how another team, this time from the University of Chicago in the US,  demonstrated a viable prosthetic that relays back sensory input in real time. This way, if you instruct the prosthetic arm to squish a ball with your thoughts, you also get a signal back from the arm to the brain so that you know if you need to keep squeezing or loosen. It’s a fantastic display of feedback. Like the system developed by the Americans, the South Korean smart skin also relies on highly sensitive sensors.

[ALSO SEE] Learning how to use brain-computer interfaces is as easy as waving a hand

After much careful planning, the sensor array was designed to have geometries that will allow it to stretch. This way, the whole array can be easily stretched and people might feel both humidity and temperature where the sensor comes into contact with matter, be it air or some surface like a hot plate. This ‘sensation’ is then transmitted from the sensor to the body through ultrathin stretchable nanowire-based electrodes.

smart-skin2

Credit: Seoul National University

The researchers also recognize that our tactile or haptic abilities aren’t the same throughout the surface of the skin. The skin is more sensitive in some parts than others, like the fingertips and lips since these areas have more receptor cells. As such, the team is considering  “location specific optimization of sensors and actuators in artificial skin and prosthetics”.

Ultimately, though, the skin needs to relay sensitivity to prosthetic’s user. This is also the most challenging part.  To achieve this goal, the signals captured across various sensor arrays must be processed and transmitted to stimulate the corresponding peripheral nervous system. For this to work, the charge delivered to the nerves must be delivered from low impedance in the multi-electrode array. There are also quite a few mechanical and biological challenges. The skin is subjected to tremendous amounts of strain and other mechanical motions. The smart skin needs to preserve mechanically conformal contacts and prevent scar formation arisen from mechenical mistmatch between the biological tissues and the electrode arrays.

The stretchable was described in the journal Nature.

hugh_herr_ted_talk

Bionic prosthetic allows disabled to run, climb and even dance – watch this TED talk!

hugh_herr_ted_talk

Hugh Herr, head of the Lab’s Biomechatronics research group, spoke at TED 2014 on March 19 about his group’s work in creating bionic prosthetic limbs, and their goal to eliminate human disability through technology.  For Herr, his work and involvement is deeply personal, having lost both his lower limbs in a climbing accident 30 years ago.

huge_herr_mit

hugh_herr_ted_talk

 

hugh_herr_ted_talk2

As he took the stage, Herr dazzled the audience as he walked to and fro wearing the latest bionic prosthetic limbs developed at his lab. Were it not for their mechanical appearance, surely no one could have noticed he had lost both his legs. His talk is deeply inspiring and extremely fascinating, as Herr lays out the work he and his group has performed over the years to reach this level of performance.

hugh_herr_ted_talk

hugh_herr_ted_talk

To the end of his talk, Herr welcomed to the stage Adrianne Haslet-Davis, a professional ballroom dancer who lost part of her leg in the Boston Marathon bombing. Herr and his team at MIT have been working for the past 200 days to build a new prosthetic limb for Adrianne.  She took to the stage with a partner and danced a rumba on her new leg—her first onstage performance since the attack.

$42,000 Prosthetic Hand OutPerformed By $50 Printed Cyborg Beast

Over the last few months, we’ve written a lot about some fantastic 3D designs which can be very useful in medicine – a cranium replacement, 3D printed skin, and especially bone and limb prosthetics. Now, 3D universe, a website dedicated to 3D printing, published an article comparing a $42.000 conventional prosthetic, with a $50 3D printed one.

Jose Delgado was born without his left hand, and in his 53 years, he’s tried several options to support his disability, recently moving onto more advanced prosthetics. For over a year, he had been using a $42,000 myoelectric prosthetic device, which took signals from the fibers in his forearm and translated them into electric signal, moving the fingers of the prosthetic hand. He was lucky enough – his insurance covered the costs, but most people in the world don’t have this luxury.

Jeremy Simon of 3DUniverse met up with Jose, and printed him a 3D prosthetic from Cyborg Beast. These are the open source 3D printed hands – anyone can take the design for free and print his or her own prosthetic. It’s really worth checking out if you or someone close to you is suffering from such a disability. At $50 for materials, it’s a very affordable financial effort.

It seems really weird to compare one thing to the other – there is a huge price difference (840 times) – both Delgado and Simon were understandably skeptical – but after testing them both, Delgado declared that the $50 one was easily outperforming the counterpart he had been using for over a year. Sure, it’s a little bit more frail, and it will probably break sooner rather than later, but the solutions is simple – you just print a new one! 3D printing is really changing the world – and it’s doing so at lower and lower prices.

Amputee feels in real-time with bionic hand

Dennis Aabo Sørensen is the first amputee in the world to feel sensory rich information (in real time), thanks to a prosthetic hand hard-wired into the nerves in his upper arm.

Credit: Lifehand 2 / Patrizia Tocci

After nine years ago he lost his left hand, Dennis Aabo Sørensen got lucky. Silvestro Micera and his team at EPFL (Switzerland) and SSSA (Italy) developed a revolutionary sensory feedback system that allows Dennis not only to move his artificial hand and fingers, but also to feel through them. A prototype of this bionic technology was tested in February 2013 during a clinical trial in Rome – and it worked out just fine.

“The sensory feedback was incredible,” reports the 36 year-old amputee from Denmark. “I could feel things that I hadn’t been able to feel in over nine years.” In a laboratory setting wearing a blindfold and earplugs, Sørensen 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.”

As my colleague Tibi Puiu wrote before, prosthetic arms (and legs, for that matter), have come a very long way. Cleveland researchers have already developed a prototype that can ‘feel’ pressure on the prosthetic, DARPA is working on solutions for veterans, and a joint team of scientists created a robotic arm that can be controlled through mind power.

Micera and his team enhanced the artificial hand with sensors that detect information about touch. In order to do this, they measured the tension in the artificial tendons that control finger movement and turning this measurement into an electrical current. Basically, they figured out a way to translate the body’s natural signals into an artificial language – and it worked like a charm.

“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,” says Micera.

“We were worried about reduced sensitivity in Dennis’ nerves since they hadn’t been used in over nine years,” says Stanisa Raspopovic, first author and scientist at EPFL and SSSA. These concerns faded away as the scientists successfully reactivated Sørensen’s sense of touch.

The clinical study is one of the first steps towards a true bionic arm – but researchers warn that a true sensory enhanced prosthetic arm is years away from hitting the shelves. The next step involves miniaturizing the sensory feedback electronics for a portable prosthetic. In addition, the scientists will fine-tune the sensory technology for better touch resolution and increased awareness about the angular movement of fingers.

Sørensen’s story is a pretty strange, yet fairly common one – he lost his left hand while handling fireworks during a family holiday. After this accident, he was rushed to the hospital where his hand was immediately amputated.

Scientists devise artificial hand that can feel

Prosthetics have come a long way in recent years alone, mainly due to advancements in brain-machine interfaces. Incredibly articulated artificial limbs can now allow a disabled individual to move an artificial hand (with up to seven degrees of freedom!) and individual fingers just by thinking about the movement the person wants  the limb to perform). While an artificial hand today may seem like a godsend to the bearer, at least compared to the complete lack of the limb or a traditional prosthetic alternative, it’s far from being the same as having a natural hand, very simply because you can’t feel. Sure you can grasp, hold, point, even shake hands, but you can’t feel anything while doing this.

The artificial hand recipient can feel touch at 20 hot spots. (c) Northwestern University

The artificial hand recipient can feel touch at 20 hot spots. (c) Northwestern University

Now, researchers at the Cleveland Veterans Affairs Medical Center and Case Western Reserve University reported they’ve devised an artificial hand that can relay back some sense of touch. We’ve presented haptic systems before, but this one works differently. Throughout the hand there are 20 sensitive hot spots, while implants connect these spots with nerve endings to relay back touch. We need to mention here that these sensitive spots continued to work even 18 months after installation, making for an important milestone since “electrical interfaces to nerve tissue can gradually degrade in performance,” according to the authors.

A firm hand-shake

Arguably, our dexterous hands are what allowed man to become the dominant species on Earth, as we could maneuver tools . Hands not only allow us to manipulate the physical, external world, but they also provide a sensory tool for perceiving reality around us. When you touch or grasp something with your hand you feel a myriad of stimuli that tell you a lot about the object you’re holding  in your hand, from temperature, to texture, to pressure and more. Also, your hands can feel extremely subtle variations of all these parameters. With this in mind, you can imagine devising an artificial hand capable of mimicking a real hand is darn challenging. We’re getting there, though.

For instance, the artificial hand developed at Case Western operates on a feedback-loop similar to neural haptics. In fact, the artificial hand can not only relay simple contact, but texture and more complex pressure sensations. For instance, in the demonstrative video embedded below, a prosthesis wearer uses the artificial hand with “touch” activated and, while blindfolded, interacts with cherries. He is able to say how hard he pressed them and whether or not he believed he squished some of them.

It really looks very promising, and while it still is confined to the lab for research, the authors are confident something similar to this could become available on the market in the next decade.  An estimated 1,715 soldiers suffered amputations in the wars in Iraq and Afghanistan, and along with thousands other sustaining amputations each year due to accidents or disease, could benefit from the artificial hand.

via TechnologyReview

 

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Granting mechanical prosthetics with touch: laying the sensory groundwork

prosthetic_hand

(c) PNAS

Prosthetic limbs have gone an incredible long way in recent years. Brain-computer interfaces, couples with incredibly articulated artificial limbs can now allow a disabled individual to move an artificial hand (with up to seven degrees of freedom!) and individual fingers just by thinking about the movement the person wants to the limb to perform. Powerful and incredible science – the kind you might have read in SciFi novels and futurists’ predictions. The future is now, but we still have a long way before these prosthetics become fully clinically viable. For one, prosthetics are missing haptic feedback. You can send an electrical brain signal to your prosthetic’s chip to instruct the prosthetic to perform an action, but you don’t get a signal back that would relay feelings like touch, pressure, contact maneuvers.  If you can make these work one way, you can sure bet you can turn this sensory communication two-way as well.

This is exactly what scientists at University of Chicago are attempting. They have yet to establish a viable prosthetic that relays back sensory input in real time, but the experiments they’ve done so far lay down the grow-work for the touch-sensitive-prosthetics of tomorrow.

“To restore sensory motor function of an arm, you not only have to replace the motor signals that the brain sends to the arm to move it around, but you also have to replace the sensory signals that the arm sends back to the brain,” said the study’s senior author, Sliman Bensmaia, PhD, assistant professor in the Department of Organismal Biology and Anatomy at the University of Chicago.

“We think the key is to invoke what we know about how the brain of the intact organism processes sensory information, and then try to reproduce these patterns of neural activity through stimulation of the brain.”

Bensmaia and colleagues made a couple of experiments on monkeys, whose neural-sensory inputs are highly similar to those of humans. The purpose of these works was to identify patterns of neural activity that occur during natural object manipulation and then induce  these patterns through artificial means.

The touch of brilliance

In the first experiment, the researchers focused on analyzing and measuring brain activity during contact – when the skin had been touched.  The animals were trained to identify several patterns of physical contact with their fingers. Researchers then connected electrodes to areas of the brain corresponding to each finger and replaced physical touches with electrical stimuli delivered to the appropriate areas of the brain. It was then observed that the animals responded to the artificial stimuli as if it came from a genuine touch.

In a second experiment, the researchers sought to relay back pressure. This time around, the researchers developed an algorithm that fed-back an   appropriate amount of electrical current to elicit a sensation of pressure. Again, the animals’ response was the same whether the stimuli were felt through their fingers or through artificial means.

(A) Upper Trial structure for all of the behavioral tasks: The cross is a fixation target or a response target, and the yellow circles indicate the two stimulus intervals. Lower: One example trial each for the location discrimination and the pressure discrimination task. The size of the cross is proportional to the depth of indentation. (B) Depiction of the triaxial indenting stimulator. (C) Electrode implants in brain areas of one of the three animals (D) Map of the implant area and corresponding hand locations. (Credit: Gregg A. Tabot et al./ PNAS)

(A) Upper Trial structure for all of the behavioral tasks: The cross is a fixation target or a response target, and the yellow circles indicate the two stimulus intervals. Lower: One example trial each for the location discrimination and the pressure discrimination task. The size of the cross is proportional to the depth of indentation. (B) Depiction of the triaxial indenting stimulator. (C) Electrode implants in brain areas of one of the three animals (D) Map of the implant area and corresponding hand locations. (Credit: Gregg A. Tabot et al./ PNAS)

In the third and last experiment, the interdisciplinary team of researchers studied contact events – grabbing, gripping, manipulating objects etc. When the monkey’s hand first touches or releases an object, a specific electrical burst is activated in the brain. After mimicking these bursts artificially, the researchers saw that yet again they could elicit a genuine response for an artificial stimuli.

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With this proof of concept, it’s clear one can develop a precise and coordinated set of instructions via brain-interface that can work in both ways: first instruct the prosthetic to perform a certain action (clench, move a finger in a particular way, grab a coffee mug etc.), second send back and analyze the feed-back signal coming from the prosthetic which the prosthetic wearer can translate into sensations.

“The algorithms to decipher motor signals have come quite a long way, where you can now control arms with seven degrees of freedom. It’s very sophisticated. But I think there’s a strong argument to be made that they will not be clinically viable until the sensory feedback is incorporated,” Bensmaia said. “When it is, the functionality of these limbs will increase substantially.”

The University of Chicago ground-breaking work has been described in a paper published online in the journal Proceedings of the National Academy of Sciences. 

The world’s first mind-controlled bionic leg

Prosthetics have been around for a very long time – the first mention of such a device is by the warrior queen Vishpala in the Rigveda, which was written roughtly some 3.500 years ago. But even with the spectacular developments of the past century, only in the past couple of decades did prosthetics really start developing at an entirely new level.

8C9162799-g-cvr-130925-leg-gif-03.blocks_desktop_smallFor 32-year-old Zac Vawter this is really great news; he lost his lower right leg in a motorcycle accident, but he’s got all the reasons to be happy: doctors fitted him with an artificial limb that uses neurosignals from his upper leg muscles to control the prosthetic knee and ankle. Basically, he was given a thought-controlled prosthetic leg which works just fine, as reported by scientists at the Rehabilitation Institute of Chicago.

“This is a groundbreaking development,” says lead author Levi Hargrove, a biomedical engineer and research scientist at RIC. “It allows people to seamlessly transition between walking along level ground and going up and down stairs and slopes.”

The technology is not really new, as it has been used for thought-controlled bionic arms several times, but it’s the first time a leg was developed using it. When the patient wants to move his leg, his brain emits an electric signal which travels through his spinal cord and the nerves in his upper leg, until it is picked up by electrodes in the bionic leg. Then, the electrodes pick up the signal from the hamstring muscles, where the nerves that had run through Vawter’s lower leg were redirected during the amputation. So when he is thinking about walking or just moving his ankle, his hamstring muscles contract, just like they would do during walking.

The prosthesis allows a normal, smooth gait regarldless of the incline.

“It makes a phenomenal difference,” says Vawter, a software engineer from Yelm, Wash., whose right leg was amputated through the knee in 2009 after he crashed his motorcycle. Aware of the institute’s work on bionic arms, Vawter and his surgeon contacted Hargrove and the team developing the pioneering prosthesis. For nearly three years ending in October, 2012, Vawter would travel to the institute periodically.

prosthetics

Although the first experiments didn’t go out just smoothly, after several software and mechanical revisions, Vawter can now walk just like he did before the accident – even up and down the stairs.

“My sound leg goes up every step first, and I’m just dragging the prosthetic leg along behind me.” But with the bionic leg, “I go leg over leg,” he says. “The bionic leg listens to the various signals from my nerves and responds in a much more natural way.”

This is just a prototype and it’s unclear just how much it would cost, though estimates range anywhere between $20.000 and $120.000. However, careful and efficient engineering can make it even more affordable.

infrared

Rats given ‘sixth sense’ after they recognize infrared light

infraredMost brain-machine prosthetic research today is focused on supplementing a missing sense, like medical devices that restore hearing or sight. In a novel research, however, scientists at  Duke University Medical Center have literally granted rodents a sixth sense after they implanted them with an experimental prototype that allows rats to “touch” invisible infrared light.

At first, six rats were trained to stick their snouts in one of the three holes in the side of a chamber from which light was emitted. Whenever the rat went to the correct  hole from which the light was emitted, it was rewarded with a sip of water.

Then  the researchers fitted the rats with an infrared detector connected to microscopic electrodes that were implanted in the part of their brains that processes tactile information. Then the same experiment was repeated, only this time light was replaced by infrared, which rats, like humans, can not sense inherently. It’s worth noting that this doesn’t necessary work with infrared only. According to the researchers a new degree of sensing could be achieved with other signals as well.

“We could create devices sensitive to any physical energy,” said Prof Nicolelis, from the Duke University Medical Center in Durham, North Carolina. “It could be magnetic fields, radio waves, or ultrasound. We chose infrared initially because it didn’t interfere with our electrophysiological recordings.”

In the first tries, the rats would seemingly hit holes at random, failing to sense the correct hole, since he part of their brains that normally process touch was interpreting the electrical signals for visual cues. This theory is backed by the fact that the rats scratched their faces when infrared was switched on, indicating the animals were interpreting the lights as touch.

However, after a while the rats’ behavior gradually changed, until all rants would sense the correct hole every time – remember, the sequence was always random.

“This is a very nice paper that clearly demonstrates the great potential of even the primary sensory cortex, even in a rat, to use completely new information when delivered to the cortex in electrical pulses,” says Jon Kaas, a professor of cell and developmental biology at Vanderbilt University and an expert on sensory and motor system organization. “The authors correctly see that this method of delivery can be used to replace lost sensory inputs and to provide new sensory abilities.”

If the same effects could be transferable to humans with a similar set-up, the possible prospects would be extremely interesting. Imagine being able to sense some forms of energy just as well as you fell temperature for instance, how would you interpret this new feeling?

Check out the video below that shows the rats sensing infrared.

The findings were reported in the journal Nature Communications. 

Researchers Develop Touch-Sensitive ‘e-Skin’

Robotics is developing faster and faster, partially thanks to the technological growth of Japan, which has quite some awesome plans for the not so distant future. This time however, it’s a team of researchers from University of California, Berkeley, led by Ali Javey that is in the spotlight.

You see, it’s not the strength that today’s robots are lacking, it’s the finesse. In order for one to do a relatively delicate task, researchers say, it would require “skin” – that is, pressure sensitive technology that would allow it to estimate the amount of power needed. The team I was telling you earlier about is working on just that.

Nicknamed “e-skin”, this technology is made of hair-thin miniaturized strips of low-voltage nanowire transistors constructed from inorganic materials.

“The idea is to have a material that functions like the human skin, which means incorporating the ability to feel and touch objects,” Javey said in a news release .

Using an innovative fabrication technique, they practically rolled and printed the nanowires onto bendable sheets of poylimide film. The end result was an artificial skin that runs on low amounts of electricity and can detect a range of pressures varying from the pressure required to type, to lifting a heavier object. Scientists hope that in turn, this technology will help develop prosthetic limbs, but this would require other advancements as well. Until then, the team will continue to work on this technology.

“It’s a technique that can be potentially scaled up,” post-doctoral fellow and study lead author Kuniharu Takei said in the release. “The limit now to the size of the e-skin we developed is the size of the processing tools we are using.”