Tag: prosthetics

Categories : Implants and ProsthesesTags :

Prosthetics Technology – Restoring a Life of Mobility, Without Limitations

On By ModernMedia

A new generation of prosthetic digits is transforming the lives of finger amputees.

Whilst small in size, the role of fingers in our overall body mobility is huge. Our fingers play a critical role in the accomplishment of everyday activities, allowing for tactile sensations and multiple fine movements from the grasping and manipulation of objects through to performing complex tasks.

Unfortunately, a significant number of finger amputations occurs each year. In fact, finger amputations account for well over 90% of all upper limb loss. The impact of this often extends far beyond the immediate area of amputation, having a much greater effect on the individual’s entire mobility.  According to the American Medical Association, losing the index and middle fingers mid-metacarpal creates a 40% impairment of the hand, 36% impairment of the upper extremity and 22% impairment of the whole body. The loss of four fingers is equivalent to a leg amputation or the loss of an eye in total impairment. [1]

The role of prosthetics in assisting these amputees to lead a far more mobile and functional life has come a long way. Traditionally, prosthetic fingers were only cosmetic and not functional. However, innovations in prosthetics technology have revolutionised this, enabling partial hand and/ or finger amputees to not only return to work but, as importantly, to a life without limitations. A recent report by the National Library of Medicine, stated that, “Over the past decade, significant advances have been made in 3D-printed prosthetics owing to their light weight, on-site fabrication, and easy customisation.” [2]

“Technology has struggled to provide relevant and fit-for-purpose solutions, leaving a void in the market,” says Ernst van Dyk (Managing Director, Össur South Africa). Össur, a global provider of non-invasive orthopaedics, recently announced its ownership of Naked Prosthetics – a provider of functional devices for partial hand and finger amputees. Making use of traditional machining, injection moulding and 3D printing, Naked Prosthetics develops and makes customised, robust and functional prostheses.

“We offer a fully customisable prosthetic finger design that allows the amputee full finger functionality,” continues van Dyk. These biomechanical prosthetic fingers are designed to replace partial or total loss of the fingers and functions exactly as a finger would. Further, the prosthetic, a non-motorised device, uses the remainder of an amputee’s finger to power the device.

Using sizing rings and photos specific to each amputee, the devices make use of a very high-end 3D printer to create the simple, elegant and fully functional device. Working with physicians, surgeons and prosthetists, each prosthetic finger is customised to the exact needs of each individual patient. Each affected finger receives a custom design to restore digit length, joint spacing and range of motion, accounting for a user’s unique amputation level and joint capability. Beyond the functional design, each has been tested for structural integrity and fatigue life.

Using mass-customisation and novel design, Naked Prosthetics’ fingers restore natural motion, dexterity and strength and are the result of strong collaboration between experienced engineers from aerospace, robotics, prosthetics and product development together with clinicians and patients. A strong focus on engineering design means that the devices are kinematically and structurally optimised to account for both the capabilities of the patient’s driving joints and the conditions under which the devices are used. Each device is designed with a safety factor above and beyond any forces the user will experience and can be used in virtually any environment.

Operated by the user through intuitive movement and driven by remaining intact joints, these prostheses require little acclimation and restore digit dexterity and hand strength without specialised training. Users report that with time these prostheses feel like a part of their bodies.

“Once a customer is fitted with their prosthetic finger, it is only a matter of weeks or months before they are fully functioning,” continues van Dyk. “Although the finger, or a portion of the finger is gone, the vibration of what is left sends a message to the brain allowing it to re-map and bring back function.” These functional, high-quality finger devices aim to restore the user’s ability to perform daily tasks, support job retention and encourage an active lifestyle.

Products such as these were not possible until only a few years ago. Says van Dyk, “Detailed CAD technology and 3-D printing makes it possible to mass-produce mechanical prostheses. It includes our custom body-driven devices (PIPDriver, MCPDriver, and ThumbDriver) that are designed for the unique shape of each patient’s hand and fingers after their amputation as well as the GripLock Finger (a passive, positionable device for those who suffered complete finger amputations or were born with congenital anomalies).” The GripLock Finger weighs in at an industry best of 25 grams and can hold up to 90 kilograms. These prostheses, made from aluminium, stainless steel, and medical-grade nylon (with a conductive tip that works on smart touch screens), are strong and rugged.

“The prevalence of finger and thumb amputations and the impact of this on the lives of these amputees deserves a high level of care,” says van Dyk. “Whilst development of prostheses has been impeded by technical and anatomical challenges, a new generation of practical, durable and body-driven prosthetic digits can enable care teams to address an unmet need and transform the lives of people who have undergone finger amputation.”

[1] April 2021 O&P Almanac by AOPA – Issuu

[1] Functional improvement by body-powered 3D-printed prosthesis in patients with finger amputation – PMC (nih.gov)

Categories : Implants and ProsthesesTags :

Össur South Africa Extends its Range of Non-invasive Prosthetics with Naked Prosthetics for Finger and Partial-hand Amputations

On By ModernMedia

Össur South Africa has announced the availability of Naked Prosthetics to the local market. This range of custom-made prostheses, precisely tailored to the user’s amputation and individual hand structure, positively impacts those with finger and partial-hand amputations by providing functional finger prostheses of high quality.

“Partial hand limb loss is the most prevalent of upper limb loss, with over 90% of upper limb amputations involving the fingers. Finger and partial-hand amputations also accounts for a significant number of amputations each year,” says Ernst van Dyk, Managing Director, Össur South Africa.

Whilst more common amongst working age men, finger and partial-hand amputations occurs regardless of gender or age. “The lack of mobility resulting from a finger and partial-hand amputation is not limited to the area of amputation only. Many amputees experience loss of mobility beyond the area of amputation,” stresses van Dyk. No fewer than 5% experience a resultant impairment of the entire body and as many as 75% of heavy manual labourers are unable to return to work.

“With Naked Prosthetics we are dedicated to positively impacting the lives of finger and partial-hand amputees. We aim to provide them with functional, high-quality solutions that seamlessly integrate into their lives and empower them to not only resume employment but, as importantly, to engage in the activities they love, thereby assisting them to live a life without limitations,” says van Dyk.

Naked Prosthetics’ innovative solutions, the result of strong research and development (R&D) efforts and manufacturing capabilities, has been recognised by Business Insider as one of the medical technologies that are changing people’s lives[1]. It currently offers four custom-designed devices that are fabricated to within millimetres of a patient’s unique anatomy to mimic the complex motion of a finger.

  • The PIPDriver is a body-controlled prosthesis designed for a finger amputation or limb difference on the proximal or distal phalanx. Its design is anatomically adapted to the proximal and distal interphalangeal joints for intuitive and natural movements. Benefits include improved functionality for everyday activities. It is easy to clean and care for, easy to put on and take off and has a cage-like structure that protects the residual finger. Its slim and smooth design allows the prosthesis to be worn on two or more adjacent fingers. It also includes a conductive tip option for touchscreen operation.
  • The MCPDriver is a body-driven prosthesis designed for a finger amputation or limb difference on the MCP joint (also known as the knuckle) of the index, middle, ring, and/or the little finger. It restores the original finger length, thereby helping to imitate natural gripping patterns and excels at restoring pinch, key, cylindrical and power grasps as well as grip stability. Its durable stainless-steel linkages and robust components allow the user to return to a highly demanding lifestyle. Benefits include a silicone pad that cushions the backplate for improved comfort, interchangeable silicone adjustment inserts that can be used to vary the volume and adjusting discs to obtain the best possible fit. Its natural abduction and adduction allow for intuitive use. As a result, the acclimatisation time after the initial fitting can be considerably reduced. It also includes the conductive tip option for touchscreen operation.
  • The ThumbDriver is a body-controlled prosthesis designed for an amputation or limb difference on the MCP joint of the thumb. It can restore two and three-point grips, enable secure gripping patterns with medium to large diameters and improve fine motor functions and skills. It features an adjustable preflex option that allows you to adapt the prosthesis according to the requirements of the task at hand. As a result, functional gripping patterns can be more easily attained.
  • The GripLock Finger is a passive and positionable prosthetic finger designed for a finger amputation or limb difference on the MCP joint of the index, middle, ring, and/or little finger. It is intended for use in conjunction with a custom-made socket adapted by a certified prosthetist. You can flex the finger to various degrees with your other hand or on a hard surface. Subsequently, you can release and fully extend the GripLock Finger by pressing the latch (lever arm) on the back or flexing the finger beyond the last locking position. It restores the original length, supports the use of both hands, prevents a misalignment of the metacarpal bone and provides a valuable tool to master everyday activities.  GripLock Fingers can be combined with our MCPDriver, PIPDriver, and/or ThumbDriver.

Says Kai, a trained plant and machine operator who suffered the loss of his forefinger, middle and ring finger after a work-related accident. “Thanks to the precise adaptation to my individual anatomical conditions, the prosthesis is an irreplaceable everyday companion for me. When I come home at night, I take off the prosthesis in seconds – just like you kick off your shoes after a long day at work. I think it’s important to convey to other people in similar situations that a work accident like mine doesn’t have to mean the end of the world. You can come to terms with many situations and end up living a normal life.”

Similarly, Cara (an active member of the Finger and Partial Hand Amputee Peer & Support Group), lost two and a half fingers on her left hand due to an unforeseen accident. Prior to her accident, Cara was an avid yogi and enjoyed practicing inversions (yoga poses where the heart is higher from the ground than the head) and handstands. “I spent a year doing physical therapy to regain strength in my left hand, but I still felt as though I was struggling to hold and grip my mat as I practiced yoga,” she recalls. Every time she tried to balance her weight, she would fall backwards due to the lack of grip and support. Within one week of receiving her Naked Prosthetics PIPDrivers, Cara was able to hold a side plank during yoga. “You may feel hopeless in the moment, but it does get better. And you will be surprised at what you could learn. I am a different person now and I grew from the experience.”

“We are committed to helping digit amputees discover innovative and life-changing solutions. It’s all about function and getting people back to living full lives, without limitations,” continues van Dyk. “We believe our range of technologically advanced and custom-made prostheses helps to achieve exactly this and we are excited to be able to offer it to local amputees.”

To find out more, please visit: https://www.ossur.com/en-za/prosthetics/np-devices

[1] Naked Prosthetics’ Technology Recognized – The O&P EDGE Magazine (opedge.com)

Categories : Implants and ProsthesesTags :

‘Cyberpunk’ Inspired Finger Prostheses will be Available to All via 3D Printing

On By ModernMedia

A groundbreaking, easy-to-use 3D printable finger prosthesis created by a recent University of Houston graduate could offer amputees a low-cost solution to restore finger functionality. David Edquilang first designed Lunet, which doesn’t need metal fasteners, adhesives or special tools to assemble, as an undergraduate student at the Gerald D. Hines College of Architecture and Design. While standard prostheses can cost thousands of dollars, Edquilang aims to make his design open access on the internet, instead of selling it.

Edquilang explains: “Lunet began when I decided to design and 3D print prototype finger mechanisms for a prosthetic hand for fun in my free time. 2 weeks and 18 prototypes later, I created a mechanism and finger structure that closely replicated the range of motion of real fingers.”

Edquilang’s mentor at UH was Associate Professor Jeff Feng, co-director of UH’s Industrial Design program. Through a partnership with Harris Health System, Feng learned of a patient who had her fingers amputated due to frostbite. Inspired by working on an upper limb prosthesis Edquilang previously developed with student Niell Gorman, working closely with Professor Feng, Edquilang created prosthetic fingers that returned mobility to the patient, allowing her to pick up objects again.

Edquilang continues: “My professor and I were then referred to a finger amputee who lost 3 of her fingers. I applied the mechanism I created to design a finger prosthesis for her. Nearly 40 design iterations and multiple rounds of patient testing were performed to ultimately create a functional prosthesis that fit her.

His “breakthrough” came from a literal break in his design.

“After we finished working with this amputee patient, I continued to tinker with my finger designs. I intentionally broke one of my finger prototypes to see where its structural weakpoint is. It broke at the distal knuckle. This led to me having a breakthrough in the design. I added a linkage that replaces the previously rigid distal knuckle, and I stumbled upon inventing a novel finger mechanism that was more flexible and nearly unbreakable. I then set on refining the design to be more functional, easily 3D printable, and more visually appealing. Inspiration from cyberpunk art and fighter jets influenced the design. 28 design iterations and a myriad of prototypes later resulted in Lunet.”

“It feels great knowing you have the capability to positively impact people’s lives and give them help they otherwise wouldn’t be able to get,” said Edquilang.

“Not every good idea needs to be turned into a business. Sometimes, the best ideas just need to be put out there ,” said Edquilang, who graduated with a Bachelor of Science in Industrial Design last year. “Medical insurance will often not cover the cost of a finger prosthesis, since it is not considered vital enough compared to an arm or leg. Making Lunet available online for free will allow it to help the greatest number of people.”

Lunet wins awards

The prosthetic design garnered Edquilang a 2023 Red Dot: Luminary award, the highest level of recognition accorded at the Red Dot Award: Design Concept. He and Feng took home the coveted accolade at Red Dot’s ceremony last month in Singapore.

“Good results come from dedication. Extraordinary results come from experimentation. Incredible results come from a combination of both,” he said upon winning the award. He has also received a number of other accolades, including iFDesign, and national runner up for the James Dyson Award.

“David’s recent success in winning the most prestigious design awards across the world is the best manifestation of the unparalleled education and training students experience in our Industrial Design program,” Feng said. “Built upon a belief that every student is a creative individual, the program pedagogy focuses on methods of cultivating innovative minds, which is enforced with rigorous professional training.”

Lunet’s geometry inspired its name

Lunet is made up of two common types of 3D printed plastics: polylactic acid and thermoplastic polyurethane. Each finger is made up of four parts held together by plastic pins. Edquilang describes arcs and circular orbits as the foundation for the motion of the finger mechanism. The geometric basis of the design evoked the idea that the prosthesis orbits around the user’s joints like a moon, or lunet, hence the name.

Another element of Lunet’s uniqueness is that it is nearly impossible to break; other finger prosthetics can be complicated and require many parts.

“The problem with higher mechanical complexity is that these designs are less durable,” Edquilang said. “The more parts you have, the more points of failure. You need to make prosthetic fingers robust and as strong as possible, so it doesn’t break under normal use, yet you want the design to be simple. This was one of the greatest challenges in making Lunet.”

He encourages other design students not to be afraid to experiment and fail because that is often how one can learn to improve the most.

“Where the world has an abundance of problems, designers have an abundance of talent, and we should not be selfish with it,” Edquilang said.

Source: University of Houston

Categories : Implants and Prostheses Medical Research & TechnologyTags :

Mastering a Third Robotic Arm is Surprisingly Quick

On By ModernMedia
Interfaces for DoF augmentation (figure by Tobias Pistohl). From Eden at al., Nature Communications. 2022

Busy doctors and nurses may have often found themselves wishing they had an extra arm to help with a patient or help with a difficult suture. Researchers around the world are developing supernumerary robotic arms to help workers achieve certain tasks unaided, or with less strain – but how long would it take to master learning an additional limb? The answer is: not long at all. One hour’s worth of training is enough for people to carry out a task with their ‘third arm’ as effectively as with a partner, according to the results of a new study published in IEEE Open Journal of Engineering in Medicine and Biology.

A new study by researchers at Queen Mary University of London, Imperial College London and The University of Melbourne has found that people can learn to use supernumerary robotic arms as effectively as working with a partner in just one hour of training.

The study investigated the potential of supernumerary robotic arms to help people perform tasks that require more than two hands. The idea of human augmentation with additional artificial limbs has long been a staple of science fiction.

Demonstrating performing a suture with an assistant robotic arm.

“Many tasks in daily life, such as opening a door while carrying a big package, require more than two hands,” said Dr Ekaterina Ivanova, lead author of the study from Queen Mary University of London. “Supernumerary robotic arms have been proposed as a way to allow people to do these tasks more easily, but until now, it was not clear how easy they would be to use.”

The study involved 24 participants who were asked to perform a variety of tasks with a supernumerary robotic arm. The participants were either given one hour of training in how to use the arm, or they were asked to work with a partner.

The results showed that the participants who had received training on the supernumerary arm performed the tasks just as well as the participants who were working with a partner. This suggests that supernumerary robotic arms can be a viable alternative to working with a partner, and that they can be learned to use effectively in a relatively short amount of time.

“Our findings are promising for the development of supernumerary robotic arms,” said Dr Ivanova. “They suggest that these arms could be used to help people with a variety of tasks, such as surgery, industrial work, or rehabilitation.”

Source: Queen Mary University of London

Categories : Implants and ProsthesesTags :

Researchers Recreate Temperature Sense in Prosthetic Arms

On By ModernMedia
Photo by Thisisengineering on Unsplash

Researchers report recreating a sense of temperature for amputees, by heating or cooling a part of their residual limb. The results of their tests are published in Science.

Researchers Silvestro Micera and Solaiman Shokur have been keen on incorporating new sensory feedback into prosthetic limbs for providing more realistic touch to amputees, and their latest study focuses on temperature. They stumbled upon a discovery about temperature feedback that far exceeds their expectations.

“When I touch the stump with my hand, I feel tingling in my missing hand, my phantom hand. But feeling the temperature variation is a different thing, something important… something beautiful,” says Francesca Rossi.

Rossi is an amputee from Bologna, Italy. She recently participated in a study to test the effects of temperature feedback directly to the skin on her residual arm. She is one of 17 patients to have felt her phantom, missing hand, change in temperature thanks to new EPFL technology. More importantly, she reports feeling reconnected to her missing hand.

“Temperature feedback is a nice sensation because you feel the limb, the phantom limb, entirely. It does not feel phantom anymore because your limb is back,” Rossi continues.

Placing a hot or cold object on the forearm of an intact individual, will result in that person feeling the temperature where it was placed. But in amputees, that temperature sensation on the residual arm may be felt­ in the phantom, missing hand.

By providing temperature feedback non-invasively, via thermal electrodes (aka thermodes) placed against the skin on the residual arm, amputees like Rossi report feeling temperature in their phantom limb. They can feel if an object is hot or cold, and can tell if they are touching copper, plastic or glass. In a collaboration between EPFL, Sant’Anna School of Advanced Studies (SSSA) and Centro Protesi Inail, the technology was successfully tested in 17 out of 27 patients.

“Of particular importance is that phantom thermal sensations are perceived by the patient as similar to the thermal sensations experienced by their intact hand,” explains Shokur, EPFL senior scientist neuroengineer who co-led the study.

Towards realistic bionic touch

The projection of temperature sensations into the phantom limb has led to the development of new bionic technology, one that equips prosthetics with non-invasive temperature feedback that allows amputees to discern what they’re touching.

“Temperature feedback is essential for relaying information that goes beyond touch, it leads to feelings of affection. We are social beings and warmth is an important part of that,” says Micera, Bertarelli Foundation Chair in Translational Neuroengineering, professor at EPFL and SSSA who also co-led the study. “For the first time, after many years of research in my laboratory showing that touch and position information can be successfully delivered, we envisage the possibility of restoring all of the rich sensations that one’s natural hand can provide.”

Temperature feedback, from well-being to prosthetics

A few years ago, Micera and Shokur got wind of a system that could provide temperature feedback through the skin of healthy subjects, also developed at EPFL and spun-off by Metaphysiks.

Metaphysiks has been developing neuro-haptic technology, MetaTouch, which connects the body with digital worlds. MetaTouch combines touch and temperature feedback to augment physical products for well-being.

“This breakthrough highlights the power of haptics to improve medical conditions and enhance the quality of life for people with disabilities,” says Simon Gallo, Co-founder and Head of Technology at Metaphysiks.

The EPFL neuroengineers borrowed MetaTouch that provides thermal feedback directly to a user’s skin. With this device, they discovered the thermal phantom sensations and subsequently tested it in 27 amputees.

The Minitouch prototype and tests

For the study, Shokur and Micera developed the MiniTouch, a device that provides thermal feedback and specifically built for integration into wearable devices like prosthetics. The MiniTouch consists of a thin, wearable sensor that can be placed over an amputee’s prosthetic finger. The finger sensor detects thermal information about the object being touched, more specifically, the object’s heat conductivity. If the object is metallic, it will naturally conduct more heat or cold than, for instance, a plastic one. A thermode, one that is in contact with the skin on the amputee’s residual arm, heats up or cools down, relaying the temperature profile of the object being touched by the finger sensor.

“When we presented the possibility to get back temperature sensation on the phantom limb or the possibility to feel the contact with different materials, we obtained a lot of positive feedback. And eventually, we were able to recruit more than 25 volunteers in less than two years,” says Federico Morosato who was responsible for organizing the clinical aspect of the trials at Centro Protesi Inail.

The scientists found that small areas of skin on the residual arm project to specific parts of the phantom hand, like the thumb, or the tip of an index finger. As expected, they discovered that the mapping of temperature sensations between the residual arm and the entire projected phantom one is unique to each patient.

Bionic prosthetics for repairing the human body

Almost a decade ago, Micera and colleagues provided real-time sensory feedback about objects being grasped. They went on to improve touch resolution by providing feedback about an object’s texture and position information in a reliable way. Moreover, they discovered that amputees begin to embody their prosthetic hand if provided with sensory feedback directly into their intact nervous system. The added sensation of temperature feedback is yet another step towards building bionic prosthetics for repairing the human body. Fine-tuning temperature sensations and integrating these into a wearable device that can be mapped out to each patient are part of the next steps.

Source: Ecole Polytechnique Federale de Lausanne

Categories : Implants and ProsthesesTags :

UK Man to Receive World’s First 3D-printed Eye

On By ModernMedia
Photo by Victor Freita on Pexels

A Moorfields Eye Hospital patient in the UK will be the first to benefit solely from a fully digital 3D printed prosthetic eye. Steve Verze, an engineer, will go home from the Old Street hospital with only a printed eye fitted that day. He first tried his eye on November 11 alongside a traditional acrylic prosthetic.

This new 3D printing process avoids the invasive process of making a mould of the eye socket: a procedure so difficult that in children it can require putting them under general anaesthetic.

Steve said: “I’ve needed a prosthetic since I was 20, and I’ve always felt self-conscious about it. When I leave my home I often take a second glance in the mirror, and I’ve not liked what I’ve seen. This new eye looks fantastic and, being based on 3D digital printing technology, it’s only going to be better and better.”

Professor Mandeep Sagoo, consultant ophthalmologist at Moorfields and professor of ophthalmology at the NIHR Biomedical Research Centre at Moorfields Eye Hospital UCL and Institute of Ophthalmology, said: “We are excited about the potential for this fully digital prosthetic eye.

“We hope the forthcoming clinical trial will provide us with robust evidence about the value of this new technology, showing what a difference it makes for patients. It clearly has the potential to reduce waiting lists.”

The printed eye is more realistic, with clearer definition and giving real depth to the pupil. The way light travels through the full depth of the printed eye is more natural than current prosthetics, which simply have the iris hand-painted onto a black disc embedded in the eye, with no light passage through the eye.

The current process can take six weeks but 3D printing halves that time, and the scanning ensures a precise fit. 

Source: Islington Gazette

Categories : Medical Research & TechnologyTags :

New Prosthetic Arm Restores Normal Movements

On By ModernMedia
A prosthetic arm being fitted. Source: This is Engineering on Unsplash

Researchers have developed a bionic arm for patients with upper-limb amputations that allows wearers to think, behave and function like a person without an amputation.

The arm combines three important functions – intuitive motor control, touch and grip kinaesthesia, the intuitive feeling of opening and closing the hand. The developers, led by Clevelend Clinic, published their findings in Science Robotics.

“We modified a standard-of-care prosthetic with this complex bionic system which enables wearers to move their prosthetic arm more intuitively and feel sensations of touch and movement at the same time,” said lead researcher Paul Marasco, PhD, associate professor  in Cleveland Clinic Lerner Research Institute’s Department of Biomedical Engineering. “These findings are an important step towards providing people with amputation with complete restoration of natural arm function.”

The system is the first to test all three sensory and motor functions in a neural-machine interface simultaneously in a prosthetic arm. The neural machine interface sends impulses from the brain to the arm and sensory information back to the brain.

“Perhaps what we were most excited to learn was that they made judgments, decisions and calculated and corrected for their mistakes like a person without an amputation,” said Dr Marasco. “With the new bionic limb, people behaved like they had a natural hand. Normally, these brain behaviors are very different between people with and without upper limb prosthetics.
The researchers tested their new bionic limb on two study participants with upper limb amputations who had previously undergone targeted sensory and motor reinnervation -procedures that establish a neural-machine interface by redirecting amputated nerves to remaining skin and muscles. 

In targeted sensory reinnervation, touching the skin with small robots activates sensory receptors that enable patients to perceive the sensation of touch. In targeted motor reinnervation, when patients think about moving their limbs, the reinnervated muscles communicate with a computerised prosthesis to move in the same way. Additionally, small, powerful robots vibrate kinesthetic sensory receptors in those same muscles which helps prosthesis wearers feel that their hand and arm are moving. The new prosthetic arm feels grip movement sensation, touch on the fingertips, and is controlled intuitively by thinking. Cameras lets the computer see the prosthetic’s position.

While wearing the advanced prosthetic, participants performed tasks reflective of basic, everyday behaviours that require hand and arm functionality, which were compared to people with traditional prosthetics and people without amputations.

According to Dr Marasco, because the limb lacks sensation, people with traditional prosthetics behave differently than people without an amputation when performing tasks. For example, traditional prosthesis wearers must constantly watch their prosthetic while using it, and have difficulty correcting for the correct amount of force needed.

The researchers could see that the study participants’ brain and behavioural strategies changed to match those of a person without an amputation. They no longer needed to watch their prosthesis, they could locate things without looking, and they could more effectively correct mistakes.

“Over the last decade or two, advancements in prosthetics have helped wearers to achieve better functionality and manage daily living on their own,” said Dr. Marasco. “For the first time, people with upper limb amputations are now able to again ‘think’ like an able-bodied person, which stands to offer prosthesis wearers new levels of seamless reintegration back into daily life.”

Source: Cleveland Clinic

Categories : Implants and ProsthesesTags :

Liquid Metal Sensors Recreate a Sense of Touch

On By ModernMedia
Photo by ThisisEngineering RAEng on Unsplash
Photo by ThisisEngineering RAEng on Unsplash

To recreate a sense of ‘touch’, researchers have incorporated stretchable tactile sensors using liquid metal on the fingertips of a prosthetic hand. 

When manipulating an object, humans are heavily reliant on sensation in their fingertips, each of which has over 3000 pressure-sensitive touch receptors. While there are many high-tech, dexterous prosthetics available today, they all lack the sensation of ‘touch‘, resulting in objects inadvertently being dropped or crushed by a prosthetic hand.
To make a prosthetic hand interface that feels more natural and intuitive, researchers from Florida Atlantic University’s College of Engineering and Computer Science and collaborators incorporated stretchable tactile sensors using liquid metal on a prosthetic hand’s fingertips. Encapsulated within silicone-based elastomers, this technology provides key advantages over traditional sensors, including high conductivity, compliance, flexibility and stretchability.

For the study, published in the journal Sensors, researchers used individual fingertips on the prosthesis to distinguish between different speeds of a sliding motion along different textured surfaces. The four different textures had one variation: the distance between the ridges. To detect the textures and speeds, researchers trained four machine learning algorithms. For each of the ten surfaces, 20 trials were performed to test the ability of the machine learning algorithms to distinguish between the different textured surfaces.

Results showed that integrating tactile information from the fingertip sensors simultaneously distinguished between complex, multi-textured surfaces – demonstrating a new form of hierarchical intelligence. The algorithms could accurately distinguish between the fingertip speeds. This new technology could improve prosthetic hand control and provide haptic feedback for amputees to restore a sense of touch.

“Significant research has been done on tactile sensors for artificial hands, but there is still a need for advances in lightweight, low-cost, robust multimodal tactile sensors,” said senior author Erik Engeberg, PhD, an associate professor in the Department of Ocean and Mechanical Engineering. “The tactile information from all the individual fingertips in our study provided the foundation for a higher hand-level of perception enabling the distinction between ten complex, multi-textured surfaces that would not have been possible using purely local information from an individual fingertip. We believe that these tactile details could be useful in the future to afford a more realistic experience for prosthetic hand users through an advanced haptic display, which could enrich the amputee-prosthesis interface and prevent amputees from abandoning their prosthetic hand.”

Researchers compared four different machine learning algorithms for their successful classification capabilities. The time-frequency features of the liquid metal sensors were extracted to train and test the machine learning algorithms. Of these, a neural network algorithm generally performed the best at the speed and texture detection with a single finger and had a 99.2 percent accuracy to distinguish between ten different multi-textured surfaces using four liquid metal sensors from four fingers simultaneously.

“The loss of an upper limb can be a daunting challenge for an individual who is trying to seamlessly engage in regular activities,” said Stella Batalama, Ph.D., dean, College of Engineering and Computer Science. “Although advances in prosthetic limbs have been beneficial and allow amputees to better perform their daily duties, they do not provide them with sensory information such as touch. They also don’t enable them to control the prosthetic limb naturally with their minds. With this latest technology from our research team, we are one step closer to providing people all over the world with a more natural prosthetic device that can ‘feel’ and respond to its environment.”

Source: Florida Atlantic University

Journal information: Abd, M.A., et al. (2021) Hierarchical Tactile Sensation Integration from Prosthetic Fingertips Enables Multi-Texture Surface Recognition. Sensors. doi.org/10.3390/s21134324.

Categories : Implants and ProsthesesTags :

Neural Control of Prosthetic Ankle Can Restore Agility

On By ModernMedia
Female athlete with prosthetic leg relaxes on a sporting field. Photo by Anna Shvets from Pexels

A recent case study demonstrates that, with training, neural control of a prosthetic ankle with a powered joint can restore agility. 

Traditional prosthetic ankle joints result in slower walking and abnormal gaits due to the way they differ from normal human ankles in distributing walking loads. Autonomously controlled powered prosthetic ankles can restore additional function to users by providing the extra work involved in a natural walking gait. However, they are currently only designed to assist walking or standing, and not to tackle specialised tasks such as squatting.

“This case study shows that it is possible to use these neural control technologies, in which devices respond to electrical signals from a patient’s muscles, to help patients using robotic prosthetic ankles move more naturally and intuitively,” said corresponding author Helen Huang, Jackson Family Distinguished Professor in the Joint Department of Biomedical Engineering at NC State and UNC

“This work demonstrates that these technologies can give patients the ability to do more than we previously thought possible,” says Aaron Fleming, first author of the study and a Ph.D. candidate in the joint biomedical engineering department.

Most research on robotic prosthetic ankles has focused on autonomous control, meaning that the prosthesis handles the fine motions when the wearer decides to walk or stan.

Huang, Fleming and their collaborators sought to find out if amputees could be trained to use a neurally controlled prosthetic ankle to regain more control in the many common motions that people make with their ankles beyond simply walking.

Their powered prosthesis reads electrical signals from two residual calf muscles, which are responsible for controlling ankle motion, and converts the signals into commands for moving the prosthesis.

The researchers recruited a study participant with an amputation between the knee and the ankle, and fitted the powered prosthetic ankle on the participant and did an initial evaluation. Over two and a half weeks, the participant then had five, two-hour training sessions with a physical therapist. A second evaluation was conducted on training completion.

Having had the training, the participant was able to perform a variety of previously challenging tasks, such as going from sitting to standing without any external assistance or squatting to pick something up without compensating for the movement with other body parts. However the participant’s own stability, both self-reported and empirically measured in such tests as standing on foam, was dramatically improved.

“The concept of mimicking natural control of the ankle is very straightforward,” Huang said. “But implementation of this concept is more complicated. It requires training people to use residual muscles to drive new prosthetic technologies. The results in this case study were dramatic. This is just one study, but it shows us what is feasible.”

“There is also a profound emotional impact when people use powered prosthetic devices that are controlled by reading the electrical signals that their bodies are making,” Fleming said. “It is much more similar to the way people move intuitively, and that can make a big difference in how people respond to using a prosthesis at all.”

More participants are already undergoing the training, with the researchers expanding their testing to match. But before this technology is made more widely available, the researchers would like real-world testing, with the prosthesis being used in people’s daily routines.

“As with any prosthetic device for lower limbs, you have to make sure the device is consistent and reliable, so that it doesn’t fail when people are using it,” Huang said.

“Powered prostheses that exist now are very expensive and are not covered by insurance,” Fleming explained. “So there are issues related to access to these technologies. By attempting to restore normal control of these type of activities, this technology stands to really improve quality of life and community participation for individuals with amputation. This would make these expensive devices more likely to be covered by insurance in the future if it means improving the overall health of the individual.”

The researchers are currently working with a larger group of study participants to see how broadly applicable the findings may be.

Source: News-Medical.Net

Journal information: Fleming, A., et al. (2021) Direct continuous electromyographic control of a powered prosthetic ankle for improved postural control after guided physical training: A case study. Wearable Technologies. doi.org/10.1017/wtc.2021.2.

Categories : Injury & Trauma Neurology Pain ManagementTags :

New Surgery Improves Prosthetic Use and Reduces Pain

On By ModernMedia

A new type of surgery that links muscles together may improve the precision of prosthetic use and also relieve pain.

In typical amputations, the muscle pairs (such as triceps and biceps) that work together to control the joints are severed. However, an MIT team has discovered that reconnecting these muscles that are in an agonistic-antagonistic (‘push-pull’) relationship improves the sensory feedback and thus precision of the affected limb.

“When one muscle contracts, the other one doesn’t have its antagonist activity, so the brain gets confusing signals,” explained Srinivasan, a former member of the Biomechatronics group now working at MIT’s Koch Institute for Integrative Cancer Research. “Even with state-of-the-art prostheses, people are constantly visually following the prosthesis to try to calibrate their brains to where the device is moving.”

The 15 patients who received the AMI surgery were able to flex their prosthetic ankle joint with more precision than those without it, who were only able to fully extend or flex their joint.

“Through surgical and regenerative techniques that restore natural agonist-antagonist muscle movements, our study shows that persons with an AMI amputation experience a greater phantom joint range of motion, a reduced level of pain, and an increased fidelity of prosthetic limb controllability,” says Hugh Herr, a professor of media arts and sciences, head of the Biomechatronics group in the Media Lab, and the senior author of the paper.

The surgery also had a completely unexpected benefit: the reduction of pain in the amputated area, which can be from neuromas or phantom limb pain. Phantom limb pain can occur in 80% of amputess. Six of the 15 AMI patients reported zero pain. This may be significant as in the five centuries since phantom limb pain was first described, there has not been much advancement in the understanding of it.

“Our study wasn’t specifically designed to achieve this, but it was a sentiment our subjects expressed over and over again. They had a much greater sensation of what their foot actually felt like and how it was moving in space,” Srinivasan says. “It became increasingly apparent that restoring the muscles to their normal physiology had benefits not only for prosthetic control, but also for their day-to-day mental well-being.”

To treat patients who had received the traditional amputation surgery, the team is also working on using muscle grafts to create a ‘regenerative AMI’ procedure that restores the effect of agonist and antagonist muscles.

Source: Medical Xpress

Journal information: Shriya S. Srinivasan el al., “Neural interfacing architecture enables enhanced motor control and residual limb functionality postamputation,” PNAS (2021). www.pnas.org/cgi/doi/10.1073/pnas.2019555118