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 around outside on uneven ground. “The stimulation will kick in as soon as I think about [taking] a step,” he says.
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| Gert-Jan Oskam walking with the aid of brain and spine implants and a backpack computer CHUV 2022/WEBER Gilles |
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 (EPFL) 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 are contained within two 5-centimetre discs that rest on the brain’s surface, having replaced two circles of bone taken from the 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 the leg muscles.
The system is an upgrade on the first version, which Oskam received five years ago, which involved only the spinal electrodes. With this version, Oskam activated each step by making a small heel movement, which he could do because the accident hadn’t completely severed his spinal cord. The heel movements were detected by lightweight motion sensors, and this caused the spinal implants to trigger semiautomatic stepping movements coordinated by networks of neurons in the lower spinal cord.
The resulting steps allowed Oskam to walk over flat ground using a wheeled walking frame. “This gave more like a robotic stepping movement,” says Courtine.
In 2021, Oskam got the brain implant upgrade. Within a few minutes of the surgery, he was able to walk and this has led to more natural movements. “He can adjust when the stimulation is turned on and by how much. It makes the movement very fluid,” says Guillaume Charvet at the University Grenoble Alpes in France, another member of the team.
“The stimulation before was controlling me and now I’m controlling the stimulation by my thoughts,” says Oskam.
The brain-controlled system also leads to a wider variety of movements of the hips, knees and ankles, says Henri Lorach, a team member at EPFL. “He can access multiple functions.”
So far, nine people in total have received the spinal implants alone, controlling their motion either by making small residual movements of their legs, as Oskam did, or by pressing buttons on the walker. Some may now have the upgrade.
The team also has approval to try using the same approach to restore arm movements for people who are paralysed from the neck down.
“This is a beautiful piece of work,” says Zubair Ahmed at the University of Birmingham, UK. “What’s cool about it is they’re linking a lot of technologies together.”
However, the system is still in the early stages of development and would be too expensive to become widely used for other people with spinal cord injuries, he says.
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