The science of bionics has made great strides in recent years but one big challenge remains – how do you make prosthetic limbs as real as possible?
Now, researchers in Newcastle may have come with the answer in the form of a new generation of prosthetic limbs which will allow the wearer to reach for objects automatically, without thinking and which are to be trialled for the first time.
Developed by biomedical engineers at Newcastle University and funded by the Engineering and Physical Sciences Research Council, the bionic hand is fitted with a camera which instantaneously takes a picture of the object in front of it, assesses its shape and size and triggers a series of movements in the hand.
A small number of amputees have already trialled the new technology and now the Newcastle University team are working with experts at Newcastle upon Tyne Hospitals NHS Foundation Trust to offer the ‘hands with eyes’ to patients at Newcastle’s Freeman Hospital.
Dr Kianoush Nazarpour, a Senior Lecturer in Biomedical Engineering at Newcastle University, said: “Prosthetic limbs have changed very little in the past 100 years. The design is much better and the materials are of a lighter weight and more durable but they still work in the same way.
“Using computer vision, we have developed a bionic hand which can respond automatically – in fact, just like a real hand, the user can reach out and pick up a cup or a biscuit with nothing more than a quick glance in the right direction.
“Responsiveness has been one of the main barriers to artificial limbs. For many amputees, the reference point is their healthy arm or leg so prosthetics seem slow and cumbersome in comparison.
“Now, for the first time in a century, we have developed an ‘intuitive’ hand that can react without thinking.”
Recent statistics show that in the UK there are 600 new upper-limb amputees every year, of which 50% are in the age range of 15-54 years old. In the US there are 500,000 upper limb amputees a year.
Current prosthetic hands are controlled via myoelectric signals, electrical activity of the muscles recorded from the skin surface of the stump. Controlling them takes practice, concentration and time.
Fellow Newcastle researcher Ghazal Ghazaei said that using neural networks – the basis for Artificial Intelligence – can help make responses quicker and easier for users of the prosthetic hand.
Miss Ghazaei who carried out the work as part of her PhD in the School of Electrical and Electronic Engineering at Newcastle University, said: “We would show the computer a picture of, for example, a stick. But not just one picture, many images of the same stick from different angles and orientations, even in different light and against different backgrounds and eventually the computer learns what grasp it needs to pick that stick up.
“So, the computer isn’t just matching an image, it’s learning to recognise objects and group them according to the grasp type the hand has to perform to successfully pick it up.
“It is this which enables it to accurately assess and pick up an object which it has never seen before – a huge step forward in the development of bionic limbs.”
Grouping objects by size, shape and orientation, according to the type of grasp that would be needed to pick them up, and using a 99p camera fitted to the prosthesis, the team programmed the hand to perform four different ‘grasps’: palm wrist neutral (such as when you pick up a cup); palm wrist pronated (such as picking up the TV remote); tripod (thumb and two fingers) and pinch (thumb and first finger).
Led by Newcastle University, but also involving experts from the universities of Leeds, Essex, Keele, Southampton and Imperial College London, the aim is to develop novel electronic devices that connect to the forearm neural networks to allow two-way communications with the brain.
Dr Nazarpour said of the new hand: “It’s a stepping stone towards our ultimate goal but, importantly, it’s cheap and it can be implemented soon because it doesn’t require new prosthetics – we can just adapt the ones we have.”
Anne Ewing, Advanced Occupational Therapist at Newcastle upon Tyne Hospitals NHS Foundation Trust, who has been working with Dr Nazarpour and his team, said: “This project has provided an exciting opportunity to help shape the future of upper limb prosthetics, working towards achieving patients’ prosthetic expectations and it is wonderful to have been involved.”
One of the people who could benefit from the pioneering work is Doug McIntosh, 56, who lost his right arm in 1997 through cancer.
He said: “I had developed a rare form of cancer called epithelial sarcoma, which develops in the deep tissue under the skin, and the doctors had no choice but to amputate the limb to save my life.
“Losing an arm and battling cancer with three young children was life changing. I left my job as a life support supervisor in the diving industry and spent a year fund-raising for cancer charities. It was this and my family that motivated me and got me through the hardest times.”
Doug, a father of three from Aberdeen, has been working with the Newcastle team to trial the new hand and said: “The problem is there’s been nothing yet that really comes close to feeling like the real thing. Some of the prosthetics look very realistic but they feel slow and clumsy when you have a working hand to compare them to.
“In the end, I found it easier just to do without and learn to adapt. When I do use a prosthesis I use a split hook which doesn’t look pretty but does the job.”
He described the new responsive hand developed in Newcastle as a ‘huge leap forward’. Doug said: “This offers for the first time a real alternative for upper limb amputees. For me, one of the ways of dealing with the loss of my hand was to be very open about it and answer people’s questions. But not everyone wants that and so to have the option of a hand that not only looks realistic but also works like a real hand would be an amazing breakthrough and transform the recovery time – both physically and mentally – for many amputees.”
