The bionic hand that is controlled by thought alone

Milo Marinkovic used to find it difficult to put toothpaste on his brush. He couldn’t tie his shoelaces and couldn’t open a bottle or a packet of crisps. He couldn’t do anything that required two hands, in fact, because his right hand was useless. It hung limply from his arm, unable to move after a motorcycle accident damaged the nerves in his shoulder more than 16 years ago and left the lower part of his arm immobile. Years of surgery to reconstruct the nerves and repair damage had not helped and the limb caused him intense pain whenever anything knocked into it.

That began to change five years ago, after he met Prof Oskar Aszmann at the Medical University of Vienna. Marinkovic now has one of the most advanced bionic hands in the world in the place of his paralysed hand, a mechanical device that he controls by thought alone.

When I met him he showed me a life-like hand covered in a pink rubber skin (complete with lines on the fingers and palm). It whirred and whined whenever he showed me what it could do, the small motors inside springing into action as he picked things up or just opened or closed the fingers. Marinkovic had no hesitation in telling me that that bionic hand had changed his life.

Marinkovic is one of three men who have had bionic hands grafted onto their arms, under the supervision of Professor Aszmann.

All three patients had suffered what is known as a “brachial plexus avulsion” injury, in which the bundle of nerves going through the shoulder is damaged and, effectively, cuts off the hand from the rest of their nervous system.

Since surgery had not worked for any of the men, Prof Aszmann’s team tried out an experimental procedure to try to give them back some of their function.

For each of the patients, Prof Aszmann’s team started by identifying the remnants of the nerves at the ends of their injured arms. The muscles had already started to atrophy there because they had hardly been used for years but there were still tiny flickers of nerve activity.

To amplify the electrical signals in the nerves, the doctors implanted muscle and nerve tissue, taken from elsewhere in the body, into the arms. That allowed the remnant nerves in the arms to grow stronger.

The patients then had to imagine opening and closing their hands using the muscles in their arms while sensors on the skin recorded the electrical signals in their nerves. A computer turned those electrical signals into action.

For the first few months, the patients were asked to control a virtual hand inside the computer. When they tensed and relaxed the muscles in their arms, the nerves there would generate specific patterns of electrical activity.

Over many practice sessions, the computer software learned which patterns of electrical activity corresponded to which actions and animated a hand moving on the screen.

When that was working well, the patients were given control of a real mechanical hand, attached to a splint next to their non-functioning flesh-and-blood hands.

Finally, when the patients were able to open and close the mechanical hands by thought alone, their real hands were amputated and the bionic hands fitted into their place.

The procedure is described today in [**The Lancet medical journal**](http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(14)61776-1/abstract). Several years after the surgery and training, all the men were able to accomplish everyday tasks with their bionic hands, including picking up a ball, using keys and tying shoelaces.

In an accompanying comment article in the Lancet, professor Simon Kay, who carried out the UK’s first hand transplant, and Daniel Wilks, from Leeds Teaching Hospitals NHS Trust wrote:

But the final verdict, Kay and Wilks added, would depend on long-term outcomes of how the patients wear the prosthetic hands and how they behaved with their more inconvenient aspects.

Prof Aszmann acknowledges that the three examples he reports in The Lancet are just the start, and bionic hands still have a long way to go of they are to mimic real hands.

He and research teams around the world are looking at ways to allow patients to control more sophisticated bionic hands that can move fingers individually and also return sensory information (in the way our own hands do for us) so that users know when they are touching something, for example, and how hard they are gripping an object.

Marinkovic, meanwhile, has become a master at using his pioneering bionic hand.

At his apartment in Vienna, he challenged (and soundly beat me) in a few rounds of racing games on the Nintendo Wii. He told me that he particularly enjoyed playing boxing matches on the games console with his children, something that obviously require two hands to compete properly.

He poured me a drink and drove me around Vienna in his manual car without any obvious trouble. These things all sound simple to people with two hands, he kept repeating when we spoke, but they were things he had had to learn from scratch in the past few years. The bionic hand has allowed him to return to living a relatively normal, independent life.