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Getting to grips with an artificial finger

Getting to grips with an artificial finger
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Surgeons at Malmö‘s University Hospital in Sweden are used to treating patients with injured hands or fingers, but sometimes the only option they have is to amputate.

Modern prosthetics can help to restore the ability to grip or manipulate objects, to carry things or even write, but they do nothing to replace the sense of touch that goes when a patient loses a limb.

So scientists are looking into ways of mimicking the human nervous system to create artificial senses.

Researchers at Pisa in Italy are part of a team of scientists from institutions across Europe who have been funded by the European Commission to develop a biomimetic finger – that is, a man-made device that can be connected to the human brain.

At the heart of the idea is an array of pressure sensors intended to mimic the sense of touch found in the neural tactile sensors of a human fingertip.

The scientists in Pisa are convinced that they can take inspiration from nature for innovative robotics.

Researcher at Scuola Superiore Sant’ Anna, Lucia Beccai explained: “The human finger has a series of tactile receptors that allow us to feel our external environment. What we are doing is using technology to integrate a number of tactile sensors inside an artificial finger.”

Before scientists could develop an artificial sense of touch, they had to get to grips with the real thing.

At Birmingham University in the UK, they have been carrying out experiments with patients who have lost their sense of touch or who are paralysed, alongside people in tip-top health.

Researchers have been testing Mike Peysim’s sense of touch with two textured surfaces. He suffered a brain haemorrhage and he said his left arm is now virtually useless. He had to say if the test surface he was feeling was rough or smooth, and a computer analysed the activity in the brain while he analysed what he was touching.

The work at Birmingham University – which is co-ordinating the bio-mimicry project – is designed to improve the understanding of how the brain uses sensory inputs.

Professor Alan Wing said: “In the case of Mike, we have damage in one part of the brain; the rest of the brain is OK. So we learn that this part of the brain is very important for touch. So it’s very interesting to work with people who have had a stroke, who have selective deficits, and this tells us how the brain takes the information, and uses it. And if we know that then we can develop neural network which might be able to do the same thing.”

In Italy, the Pisa scientists are trying to take that knowledge about how the neural network links hand and brain, to create the world’s first artificial finger.

Their current model is able to recognize 90% of the surfaces tested.

It is the result of combining several fields of expertise, ranging from neurology to nanotechnology and robotics.

Now they are also exploring biotechnology, so they can hopefully grow artificial skin, to cover their artificial fingers.