New prosthetic arm offers users the ability to feel what they touch

'Cuff electrodes' connect the prosthetic hand to the amputee's nerves

A new form of prosthetic interface has been developed raising the possibility that future amputees might not only have their mobility restored, but also their sense of touch.

Although advances in prosthetic arms are creating increasingly dexterous limbs (and this is arms rather than legs - the latter are far simpler beasts, mechanically speaking) the ability to convey sensory input has been far less developed.

Now, researchers from the Cleveland Veterans Affairs Medical Center and Case Western Reserve University have developed a new electronic ‘cuff electrode’ that is implanted into a patient to convey a range of sensations from 20 spots located on a prosthetic hand.

The video below shows the technology in action, fitted to 48-year-old Igor Spetic of Madison, Ohio, and one of the two patients to have been fitted with the interface so far. The implant is attached to three nerve bundles in the arm – the radial, median and ulnar, with each held by seven-millimetre ‘cuffs’.

Once the cuffs have been connected to the right nerves, Spetic reported feeling like the back of his hand and fingers were being touched, when the corresponding locations on the prosthetic hand came into contact with something.

The technology differs from previous nerve interfaces as it stimulates the axon – the protective sheath that surrounds the nerve fibres – rather than penetrating this layer of living cells. Whilst this offers a lower ‘resolution’ of touch, it means the interfaces work for longer – up to 18 months as opposed to a few weeks.

Spetic told the MIT Technology Review, who reported on the technology, that “It’s real exciting to see what they are doing, and I hope it can help other people. I know that science takes a long time. If I don’t get something to take home, but the next person does, it’s all to the better.”