Towards a genuine bionic hand

At the Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland, Professor Silvestro Micera is pushing the limits of intelligent prosthetics one step further. With his team, he aims to produce a bionic arm that is fully integrated into the patient’s nervous system.

‘Our goal is to restore a bi-directional link with the nervous system, restoring the natural pathways between the brain and the muscles,’ he said. ‘Over recent years, there has been a lot of progress in the domain of artificial hands.’

For centuries, humans have replaced a missing limb with a prosthesis for many reasons:  cosmetic, vocational, or for personal autonomy. It is in this last domain that Prof. Micera, Head of the Translational Neural Engineering Laboratory at EPFL, is working.

‘We are developing electrodes to be implanted in the peripheral neural system,’ he said. ‘In this way, you can reconnect the nervous system in a more natural and potentially effective way to the prosthetic hand.’

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‘We are developing electrodes to be implanted in the peripheral neural system. In this way, you can reconnect the nervous system in a more natural and potentially effective way to the prosthetic hand.’

Improving the quality of life

‘When we grasp an object, multiple signals come down from the brain to the peripheral nerves,’ said Micera, who is also Professor at the Scuola Superiore Sant’Anna in Italy. ‘We can record them, identify the kind of task the patient plans to do, and control the prosthesis. The prosthesis, in turn, is sensorised and we can feed back the sensory information by stimulating the sensory peripheral nerves.’

How the bionic hand works. © EPFL The technology means that there is feedback between the commands issued by the brain, and the sensory information received by the prosthesis.

‘We have already tested the possibility of recreating this loop over a four-week period with a prosthesis,’ he said. ‘After many years of work, and thanks to the support of the European Commission, we are now ready to undertake our next clinical trial.’

The next step in this project will be to make the implantable electrodes suitable for long-term use, not just four weeks, and so they’ll be testing them over a much longer period of time. ‘From several months to a couple of years,’ said the researcher. ‘This will show us whether we have a suitable solution to this problem, or if we need additional developments in terms of processing, technology, controls, etcetera.’

A prosthesis controlled directly by the nervous system could have a huge impact on the life of an amputee, giving them something that comes closer to replicating the fine motor skills employed when manipulating an object with a real hand. ‘Clearly, the quality of life is significantly improved,’ said Micera.

The plan is to launch such a prosthesis within five to six years, at the earliest.