A man paralyzed from the shoulders down has been able to walk using a pioneering four-limb robotic system, or exoskeleton, that is commanded and controlled by signals from his brain. Anna Bevan reports.
A paralysed man has been able to walk again using an exoskeleton suit he controls with his mind. Although it doesn’t yet let him walk independently – the suit is suspended from an overhead harness to stop him from falling – the advance represents the first steps down the road to this goal.
“This is really groundbreaking,” says Ravi Vaidyanathan of Imperial College London, who wasn’t involved in the work.
The implanted brain sensors also let the man, who broke his neck in a fall four years ago, move the arms and hands of the exoskeleton.
But this entails having wires entering the skull, which could let in an infection. The electrodes also gradually stop working so well over the following months as they get covered with cells that form a kind of scar tissue.
To get round these problems, Alim Louis Benabid at the University of Grenoble Alpes in France and his colleagues instead put electrodes on top of the brain, resting on its tough outer membrane. “If there’s any kind of infection, it will stay outside,” says Benabid.
The researchers started by asking the man, a former optician known as Thibault, to have several brain scans so they could map which areas become active when he thinks about walking or moving his arms. Then they replaced two 5-centimetre discs of skull, one on either side of his head, with the brain sensors, which have electrodes on their underside.
Thibault practised using the sensors, first by trying to move an avatar shaped like the exoskeleton on a computer. Then he was strapped into the suit and he learned to make it start walking forwards, while supported from overhead.
“I felt like the first man on the moon,” says Thibault. “I hadn’t walked for two years. I had forgotten that I used to be taller than a lot of people in the room. It was very impressive.”