Twelve years ago, a cycling accident left Gert-Jan Oskam, now 40, with paralysed legs and partially paralysed arms, after his spinal cord was damaged in his neck. But these days, he is back on his feet and walking, thanks to a brain-spine interface. Oskam was one of the participants in that trial, but after three years, his improvements had plateaued. The new system makes use of the spinal implant that Oskam already has, and pairs it with two disc-shaped implants inserted into his skull so that two 64-electrode grids rest against the membrane covering the brain.
The skull implants detect electrical activity in the cortex, the outer layer of the brain. This signal is wirelessly transmitted and decoded by a computer, which then transmits the information to the spinal pulse generator. After around 40 rehabilitation sessions using the brain-spine interface, he had regained the ability to voluntarily move his legs and feet. That type of voluntary movement was not possible after spinal stimulation alone and suggests that the training sessions with the new device prompted further recovery in nerve cells that were not completely severed during his injury.