A revolutionary bionic hand that ‘sees’ objects and instantly decides what kind of grip to adopt has been developed by scientists.
For the first time, the hand can self-select one of four grips depending on whether it is picking up an apple or holding a pen between thumb and forefinger.
All the person in charge of it must do is glance at the object they want to pick up and picture clenching their fist.
The breakthrough, which uses a 99p ($1.30) webcam to work out the grasp needed, does away with hours of exhausting training for amputees using clumsy traditional prosthetics.
Currently they must learn up to a dozen ‘trigger actions’ – imagining precise movements to send brain signals which activate muscles connected to electrodes on their stump. That can lead to repeated frustration if the prosthetic crushes or spills what it is picking up.
The camera does all this hard work for the hundreds of British amputees, by judging an object based on a database of almost 500 items and changing its grasp accordingly.
Picking something up is claimed to take milliseconds using the device, 10 times faster than a traditional artificial hand. It is hoped the hand will be made available for NHS patients within two years.
Dr Kianoush Nazrpour, co-author of the study on the prosthetic hand, said: ‘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.’
To create the new prosthetic, biomedical engineers at Newcastle University trained a computer to recognise nearly 500 objects photographed from more than 70 different angles.
This allowed it to judge the right grip, such as a pinch between thumb and forefinger to pick up a pen or the ‘palm wrist pronated’ grip to pick up a television remote.
The other two grasps are the tripod, using thumb and two fingers to pick up a stapler, for example, and the ‘palm wrist neutral’ grasp to hold a cup of tea.
Tested on two amputees, it picked up objects with an accuracy of up to 88 per cent, compared to a rate of around 95 per cent for existing prosthetics.
Amputee Doug McIntosh, 56, was one of the first to try out the ‘seeing’ hand and described the experience as ‘completely mind-boggling’.
The 56-year-old from Aberdeen, who lost his right hand and forearm to cancer in 1997, was able to pick up a small bottle, a CD and a credit card. He said: ‘It’s quite emotional when the thing comes to life. It was almost like a flashback to the last night before I had my amputation, but it was emotional in a good sense.’
The prosthetic hand swivels its camera and starts to pick up an object only when the user glances at it and activates their muscles by imaging clenching their fist.
The same action can be repeated to reverse the movement if, in a cluttered home, the hand goes to pick up the wrong item.
The camera-mounted hand is hoped to be rolled out to people at Freeman Hospital in Newcastle within two years.
|A camera fitted to the hand (pictured right) rapidly takes a picture of the object in front of it and feeds the information to an electronic ‘brain’|
There is criticism that using just one trigger action for a prosthetic hand could cause other muscles left unused by amputees to wither away, but this is refuted by the Newcastle team.
Dr Jeroen Bergmann, a wearable technology expert from the University of Oxford, said: ‘Robust control of artificial limbs is essential and although at the moment further improvements are still needed to make the technology described in the paper applicable in the real-world, it is likely that in the future prosthetic control can benefit from this kind of development.’
The research is part of a larger project to develop a bionic hand that can sense pressure and temperature and transmit the information back to the brain
Every year in the UK around 600 people suffer the loss of upper limbs, half of whom are aged 15 to 54.
In the US, there are 500,000 new upper limb amputees each year.