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.
Prosthetics have made amazing advances in recent years – and are slowly changing people’s attitudes to disability. By Patrick Kane
I was born with the usual set of limbs. When I was nine months old, I contracted meningococcal septicaemia, a dangerous infection of the blood, which very nearly killed me. I survived, but because I had sustained major tissue damage, it became necessary to amputate my right leg below the knee, all of the fingers on my left hand and the second and third digits on my right hand. I learned to walk on a prosthetic leg at the age of 14 months, and have gone through my life wearing a succession of artificial limbs.
As time has passed and technology has advanced, so too have my limbs. Like our mobile phones, prostheses have become lighter, faster and more efficient. When I was nine, I was fitted with a lifeless silicone hand, a useless thing that was purely cosmetic, and so clumsy that I refused to wear it after the first day. Now, at 21, and a student in my third year at Edinburgh University, I wear a bionic arm with nimble fingers that move independently, which I operate using controlled muscle movements in my forearm, as well as an app on my phone. As a child I wore a stiff artificial leg attached with straps that frequently fell off; earlier this summer, I took delivery of a new dynamic right leg with shock absorption and carbon fibre blades.
Prosthetics have been around for more than 3,000 years: wooden toes, which strapped on and were specifically designed to work with sandals, were found on the feet of Ancient Egyptian mummies. For most of history, prosthetics have been designed to make life more comfortable for adults, to afford the wearer some limited movement, and to avoid drawing attention to their disability (by filling an empty jacket sleeve, or concealing a stump). It is only recently, as advances in robotics and computing power have been incorporated into artificial limbs, that function has become paramount, and the needs of active disabled people, especially children, have begun to influence design.
Until May this year, the leg I wore was fairly simple: a carbon fibre socket fastened with a pin, and a titanium pole attached to a waterproof foot. It certainly got me around, but it had its limitations, especially on uneven surfaces such as cobbled streets, pebbled beaches and any significant slopes – which, incidentally, describes most of Edinburgh.
In April 2016, I started working with Össur, a prosthetics developer that makes hi-tech joints and limbs for amputees, and has pioneered a new kind of attachment that helps balance and weight-bearing. Two years later, on a bright and chilly May morning, I drove to the Pace Rehabilitation centre in Stockport, where a physiotherapist would fit me with a new leg. I was a little nervous, since I had been going to the same prosthetics centre in Hampshire since I was two, but now that I spend a lot of my time in Scotland, the drive had become too long. Paul, my new prosthetist, met me at the door. I had spoken to him at an Össur training day some months before, and there was no danger of forgetting him. He has tattooed sleeves down both arms, long hair tied back in a ponytail and a strong Geordie accent, but what I remembered most was how many questions he asked.
Paul and a physiotherapist asked a ton of questions and filmed me walking the length of the room several times. They noticed that my old right leg was about an inch too short, a fact that had never occurred to me. When they were satisfied that they had all the information they needed, they made a full plaster cast of my leg. Just three hours later, a simple test socket had been mounted on to the new technology. As Paul described each component and how it is designed to help me move, it was hard to not start planning a marathon in my head.
The top of the new leg has a carbon fibre socket and is attached by vacuum. This evenly distributes the pressure, and won’t tug on any part of my stump, meaning I will no longer have the permanent, painful love-bite where the pin used to pull too hard on my skin. Below a titanium connecting component, there is a large hollow rubber sphere, which provides torsion – the ability to rotate. Dual carbon fibre blades curl into the hollow plastic foot. The blade in the foot is split in half, along where your big toe is. This is so the foot can deal with uneven ground (it also means I can wear flip flops). A small carbon fibre lever rests on top of the blade within the foot. Each time I take a step, my body weight bends the foot slightly, pushing the lever and drawing air out of the socket. It is designed to mimic a human foot as closely as possible, and it all looks very cool.
My first steps in the new leg were unsteady. As I put my weight through the prosthesis, I felt the heel compress and naturally rolled my weight on to the front of my foot, which then pushed me off with the toes. It turned out that I had been putting a lot of effort into walking on my right leg. All of a sudden, my new leg was putting effort back into me. It was extremely comfortable, and I left the clinic after five hours with a spring in my step. I even fancied going for a stroll. Previously, walking was a considerable effort and I wouldn’t do it unless it was necessary, but that evening, I found myself walking around my friend’s garden for the sheer pleasure of it, for the first time I can remember.
I had been a healthy baby, and the first sign that anything was wrong with me came after an unsettled night’s sleep. This was nothing too alarming for a baby of nine months, and my parents went to work that morning as normal, leaving me with my nanny, Sandra. By the afternoon, I was vomiting, floppy and drowsy. Within a few hours I would be fighting for my life.
My mother was at work, and booked a taxi to take Sandra and me to the GP, which was near our house in west London. The GP did not think it was anything too serious, and recommended Calpol: the liquid paracetamol that is a staple in every family’s medicine cabinet. Not quite content with this, my mother, still on the end of the phone, got the taxi to take me to the clinic at St Mary’s hospital in Paddington, less than a mile away. This geographical accident, and my mother’s persistence, saved my life.
At the hospital, I was received by Dr Parviz Habibi, one of the founders of the paediatric intensive care unit at St Mary’s. I spoke with Habibi recently, and he talked me through my arrival with such clarity that you would have thought it happened a couple of weeks ago. Within an hour, I had developed a meningococcal rash, which spread over my entire body. Habibi and his team recognised the signs and hooked me up to a catheter inserted in a large vein in my chest, to give my body the fluids it needed. But the intesive care unit’s medical devices were just not designed for a child that young, and my skin began to stretch and split as fluid leaked from my capillaries. I ballooned to four times my weight in a matter of hours.
Six hours after my arrival, multi-organ failure set in, affecting my kidneys first, then my blood, heart and lungs. Habibi recalled that it was in these first hours that most of the damage was done to my body, and the rest of my nine-week stay in hospital was spent solving the problems caused on the first day. My baptism was originally set for St Patrick’s Day, but because my parents were afraid I would die, it was dragged forwards to the evening of my second day in hospital, with close family and friends awkwardly huddled between the tubes and blinking machinery keeping me alive.
It was among these beeping boxes and flashing lights that my mother slept, vowing not to leave hospital until I did. People handle these traumatic situations differently, and my mother’s way of coping with it was to master the machinery of my care. She made it her mission to understand every tube’s purpose, know which light meant what, and alert a nurse as soon as there was a change on the monitors. I have no recollection of ever being ill, and had no sense of “fighting” the disease; however, I do often think of the strength shown by my mother in those months as an inspiration. When my five-year-old sister, Rosie, decided this had all gone on long enough, she stormed into my room and shouted, “Wakey wakey, Patrick!” For the first time in almost a month, my eyes flickered open.
Over the following days and weeks, different problems arose. I had become addicted to morphine, which I had been given for pain relief. My father vividly remembers seeing my body going into spasms of withdrawal. Once I was weaned off the drug, which took a few days, I was stable enough to be transferred from intensive care to a high-dependency ward. This, strangely, was the most testing time for my family. My mother had taken comfort in understanding the medical machinery and on the new unit, there was none. Without the monitors for reassurance, she felt lost and helpless.
Moving out of intensive care also meant I was well enough to undergo surgery again. Over the weeks, a few of my fingertips had become blackened and gangrenous, because not enough oxygenated blood was getting to them, and my family had expected me to lose some of them. But the blackening spread, including to both of my legs. Somehow, my left leg returned to normal after a few hours, but the right leg stayed black. When this happened, it meant the tissue was dead, so there was no choice but amputation. Each time I went into theatre, my parents would see me return with yet another bandaged stump hanging from me.
My entire life, people have been asking what happened to me, and when I tell them the story they always respond “poor you, how awful”. I have never seen it this way. The fact that I had come so close to death at such a young age had a profound effect on my parents’ attitude to my disability: because they were aware that things could have gone much worse, they did not have, and did not pass on, a “poor me” attitude. I have no memory of those months: I was not the one experiencing the stress and trauma of my illness. It was not until I was much older that I realised what the impact must have been on my family.
Prosthetic legs don’t have barcodes. My mother and I discovered this on a trip to the supermarket when I was about two years old. I used to sit in the child seat of the trolley, with my cumbersome prosthetic leg held on with several straps. Between the frozen produce and the fresh fish my mother heard a clunk, following by loud gasps from everyone else in the aisle who had just witnessed my leg falling off. This was common enough; my mother picked it up and put it in the trolley with the groceries. It would be too much hassle to put it back on there and then, so it could wait until we were in the car. At the till, one item after another went through the scanner, until the cashier’s hand reached for the leg, its little shoe still on. The poor woman was stunned.
I had a normal childhood. It was only in moments like this that we realised it was not quite so normal for everybody else. Three months after I left hospital, when I was 15 months old, we all went on a family holiday to Marbella. My arms and legs were healed up by then, and I was getting the hang of using my stumps to crawl around and hoist myself up on to tables and chairs. One day my sister came running to my mother, crying. One of the other children had told her that her little brother was “disgusting”.
It was not long after that holiday that I was fitted with my first prosthetic leg, and by the time I was 18 months old, I could walk. But it’s hard to design legs for babies. The first ones I used were awkward, and often fell off. My parents found Dorset Orthopaedic, a private clinic near Salisbury that was able to tinker with the standard procedure, initially adapting an arm socket for my leg, to get a better fit. These new prosthetics were up to the task of keeping up with my daily habits, and were designed to look as much like my leg as possible. The flesh-coloured “skin” had the consistency and texture of a fabric bandage, which punctured or tore easily with a fall. I would grow out of one every six months between the ages of three and 18. They weren’t waterproof, but I would always use my most recently discarded leg to go in the water to swim. By the time I was done with a leg, it often looked like I had been attacked.
The legs allowed me to play however I chose. But the prosthetics, and the private clinic, were very expensive. They were only available to me due to another incredible stroke of good fortune. At the time, my father was working for Sunday Business, a weekly financial newspaper, which was owned by the Barclay brothers – the British billionaire twins who also own the Daily Telegraph. Sir David Barclay read about my illness and wanted to help, so he set up a fund to pay for my prosthetics. I am acutely aware that most amputees do not have this possibility. The NHS simply can’t afford to support the cost of this technology.
My parents’ attitude was that I should do everything my siblings did, and when I went to pre-school, I was expected to do everything the other kids could. This meant that I could discover my own limits, rather than have them defined for me by others. It turns out, apart from wearing only shoes with Velcro straps and being slightly less gifted on the recorder, I didn’t have too many issues.
In my first “show and tell” at school, I brought in a sack of prosthetic legs, and it was received as a cool, exciting thing, rather than something to hide. I was fearless, and my choice of legs soon began to reflect this – going from fleshy imposters to bright blue and covered in postage stamps, and even a waterproof leg decorated in leopard print.
I discovered early on that I didn’t want to fit in, if it was at the cost of my own ability to function. While I used a series of prosthetic legs, I carried on using the stump of my left hand effectively, learning to touch type and single-handedly beating my friends at Fifa. When I was about nine, I tried a false arm. My left arm is short, due to damaged growth plates, and all of the fingers are amputated at the knuckle. It looks like half an arm, but it has always been useful, allowing me to hold objects against my body, or to push with. The false arm had a silicone cosmetic glove that fitted over my stump, complete with wrinkles and realistic nails. It was a beautiful looking thing, but I hated it. It was entirely passive, and just sat there. I found that it removed the function I had with my stump, such as typing or catching a ball, and was only there to appease other people’s idea of “wholeness”. I wore it for one day and then never again. I think it was some time before my family understood my decision.
This all changed in 2010, when I was 13, and my stepfather saw an advert in the newspaper for the i-limb pulse, which claimed to be the most advanced prosthetic hand in the world. He phoned the Scottish company that made it, Touch Bionics, and we arranged to meet them. I was doubtful about the benefits of a fake arm: I was functioning very well with Velcro shoe straps, and I could always get family members to cut up my food.
The team from Touch Bionics demonstrated how the hand worked, and checked the muscles in my forearm that control the hand.
They showed me the different looks the hand could have, including skin-toned silicone. I wasn’t interested in imitation flesh, and asked if they had anything that showed off the technology better. They pulled out a semi-transparent thin glove with pointed fingers, through which the robotic components can be seen. It looked perfect.
The hand has slender, elegant black fingers powered by individual motors, which allows each finger to move separately from its neighbours, and to wrap around unusually shaped objects, just as a real hand does. The hand attaches to the socket with a twist motion, and can be removed by rotating it a full 360 degrees. The socket, containing the batteries, wires and electrodes, extends just past my elbow.
The whirring noise of the motors was pure science-fiction. The team from Touch kept telling me I shouldn’t get my hopes up, as there was a chance I wouldn’t be able to use the technology, but it was proving impossible not to get excited about becoming the Terminator. I was fitted with the arm a few months later, and aged 13, became the youngest person in the world with a bionic arm.
My life was transformed by my new arm. Everything got easier. I used to open bottles of water by clamping them between my thighs and twisting with both hands, but now I simply hold the bottle in my firm bionic grip and twist with the other. I noticed that it also changed how others perceive me. No longer did I get looks of pity when walking in public. Instead, the looks I got changed to genuine curiosity at this robotic device. People would approach me to say, “I just have to know what this is and how it works.” I have discovered that people would much rather talk about these things – they just don’t know if it’s allowed. The non-realistic look of the hand is a message to others that I am happy to talk about it.
The hand operates very simply. There are two electrodes that touch my skin when I place my arm into the socket. One of them is responsible for opening the hand, the other for closing it. All I have to do is send a muscle signal. I had a week’s training when I was first fitted with the hand, to teach me how to separate the signals, by twisting and bending my wrist, so I could send each one separately and clearly.
I would upgrade to newer generations of the hand as they emerged, every few years, each better than the last. But I would also need to get a new socket every year or so, as the shape of my arm changed as I grew. My current hand, the i-limb quantum, has titanium digits for increased weight bearing. An app on my iPhone sets the fingers into one of 36 different grip patterns, allowing me to get the right configuration for a specific task, from using a spray cleaner to operating a computer mouse. After more than eight years of practice, I can control the arm to the extent that I can hold a grape between my thumb and forefinger, and squish it on command.
By the time I was 13, my stepfather took over paying for my prosthetics. These devices cost around £20,000 and I was extremely fortunate that my family could afford it. The biggest cause of amputation in the UK is vascular disease, although in younger people, trauma is more often caused by accidents, especially in cars. Sophisticated knee joints have recently become available through the NHS, and the hope is that, in the future, multi-articulating prosthetic hands could become routinely available. But for the moment, they remain out of reach for most people.
I’m acutely aware that my position is extremely privileged, so I see it as an obligation to speak about what happened to me. In 2013 I became an ambassador for the UK Sepsis Trust, and help them to raise awareness by giving talks and doing interviews. In 2015, I became an ambassador for Touch Bionics. I receive free upgrades to the hand in return for helping with research and development of the device. I give them feedback about specific things – such as which grip patterns I use, or how long the charge lasts (two days). I have told them I won’t be fully happy until I can juggle – and I’m only half joking. The hand currently goes from fully open to fully closed in 0.8s, so we still have a way to go.
As an ambassador, I regularly meet other amputees, usually at conferences, where they are looking at the different products. In 2016, Touch Bionics was bought by the Icelandic prosthetics company Össur, founded in 1971 by Össur Kristinsson, the inventor of a revolutionary silicone interface for prosthetic sockets. When I was working with Össur representatives in China, one of them said something I had never considered before: “We have a duty to our customers that other businesses do not, because nobody chooses to need our products.”
The vast majority of amputees do not have access to either the technology or the expertise needed to fit these sophisticated devices. In China, on a visit representing Össur, I spoke to many people who couldn’t afford the latest technology, and had ill-fitting sockets, or limbs they had grown out of, sometimes causing discomfort and injury. “Recycling” old limbs is always difficult, because every person’s residual limb is unique. With more than 1 million new amputees each year globally, the need to make these resources more widely available is increasing. Fortunately, the continued advance of technology such as 3D printing has the potential to bring prostheses to parts of the world where there are no specialist prosthetic teams.
Although I lost part of my right leg and left arm as a baby, it’s only recently that I’ve learned that I am disabled. For most of my childhood, I avoided the word, scared of having it pinned on me. Disabled things are broken and they don’t work. When you enter the password incorrectly too many times on your iPhone, it becomes disabled. I always preferred to be called an amputee, as this says what happened to me without making assumptions about my ability.
The greatest ambition of amputees used to be to fit in, and be normal. I have noticed that it’s partly a generational thing: older people generally aim to make their prostheses as lifelike as possible, and there can be an amazing level of detail involved in making them look lifelike, complete with hairs, moles and tattoos. But for a lot of young people, the priority is function. The new generation of prostheses don’t look like human limbs, and they’re not supposed to blend in. Some of the legs I have seen over the years have had flames, football logos and even speakers. The running blades developed for use in sport are made of woven carbon fibre in a large C-shape, which looks nothing like a leg, but functions very well indeed.
Technology is key to changing perceptions, and does far more than previous generations of well-meaning awareness-raising campaigns have done. The portrayal of bionic characters as superhuman and powerful is helping to shape society’s attitudes towards disability. The change may be slow, but as technology continues to improve, perceptions are evolving. I am sure there will come a time when there won’t have to be a trade-off between function and looks, but even then, will we want these devices to look normal? The more closely something imitates real life, the more jarring it looks. I still enjoy standing out from the crowd.
Although I have made a great effort not to let myself be sidelined by disability, I have also learned that it’s important not to distance myself from a marginalised group just because privilege has taken me somewhat out of it. The sobering truth is that I am – as many disabled people are – just one incident away from seriously struggling. In January I dislocated my knee, and since I can’t use crutches, I couldn’t leave my flat for three days. I had flatmates to bring me food from the shops, but I could not help but think about how helpless I would have been if I was living alone.
While doing research for this piece, I came across one written by my father in 1999. “This time last year my nine-month-old son, Patrick, was as close to death as it is possible to be,” it began. Reading that piece today, it’s hard not to be struck by how far we have come in the 19 years since it was written. The overriding tone was one of worry about what the future might hold for me, and how my life would be difficult. One line in particular stood out: “Barring major advances in medicine, he will never be able to use his left as a normal hand.” When I asked my father about that article recently, he said: “I was wrong, on two counts. Prosthetic technology has been more innovative than I could have imagined. And you have been far more resilient and determined then even I could have known back then.”
Technology is playing an important role in redefining disability, but attitudes are going to have to adapt, too. There are more than 13 million disabled people in the UK, yet a recent survey by Scope reports that 67% of the British public feel uncomfortable talking to disabled people: 21% of 18- to 34-year-olds admit they have avoided talking to disabled people because they were unsure how to communicate with them.
Occasionally I am reminded of the gap between the way I see my disability, and how the rest of the world sees me. When I was 18, I was contacted by an assistant TV producer who had seen my TEDxTeen talk about disability and wanted to know if I would appear on the dating show she was working on. She sent over an email promising it would be shot tastefully and “sensitively portray my search for love”. Wary of the voyeurism of this kind of show, I declined. I later learned that I had been invited to appear on the astoundingly named Too Ugly for Love? The show ran for three seasons, which says a lot about how much work is still needed to change attitudes towards disability.
Advanced prosthetic technology will force a change in public attitudes, as they blur the gap between disability and ability. We have Olympians arguing that legless amputees should not be allowed to compete against them, in case they have an unfair advantage, which would have been tough to imagine at the time of the first Paralympic Games in 1960. Blind people are having their vision restored by cameras, paraplegic people are learning to walk again with powered exoskeletons and I can control my bionic hand with an app on my phone. But sometimes really significant change is more straightforward. It can be as simple as me being able to tie my own shoelaces, and walk away.