Health
A DUTCH man who was paralysed after breaking his neck can now walk with crutches after receiving implants that let his brain send signals to his spine through a computer in a backpack.
Gert-Jan Oskam, who is 40, can now stand up from a seated position, go upstairs and walk on uneven ground. “The stimulation will kick in as soon as I think about [taking] a step,” he says.
Oskam has also found that even when the device is turned off, he is able to walk short distances with a wheeled walking frame. Grégoire Courtine at the Swiss Federal Institute of Technology in Geneva and his colleagues, who developed the technology, think this may be because the repeated exercise has stimulated regrowth of nerve cells in the spine.
The brain implants sit in two 5-centimetre discs that rest on the brain’s surface, having replaced two circles of bone taken from his skull. They communicate wirelessly with a helmet-like receiver, which sends signals to the backpack computer. The computer then sends signals to stimulators put into Oskam’s spinal cord, which trigger movements of his leg muscles (Nature, doi.org/gr9b5x).
The system is an upgrade on the first version, which Oskam received five years ago, involving only spinal electrodes. With that version, Oskam would make a small heel movement, which he could do because the accident didn’t completely severe his spinal cord. Motion sensors detected the movement and caused the spinal implants to trigger a semiautomatic step coordinated by networks of neurons in the lower spinal cord.
“This gave more like a robotic stepping movement,” says Courtine. It allowed Oskam to walk on flat ground using a wheeled walking frame.
