by Gert-Jan Oskam was living in China in 2011 when he had a motorcycle accident that left him paralyzed from the hips down. Now, with a combination of devices, scientists have given him control over his lower body again.
“For 12 years I’ve been trying to get back on my feet,” Oskam told a news conference on Tuesday. “Now I learned to walk normally, naturally.”
In a study published Wednesday in the journal Nature, researchers in Switzerland described implants that provided a “digital bridge” between Oskam’s brain and his spinal cord, bypassing injured sections. The discovery allowed Oskam, 40, to stand, walk and climb a steep ramp with only the help of a walker. More than a year after the implant was inserted, he maintained these skills and showed signs of neurological recovery, walking with crutches even when the implant was disconnected.
“We captured Gert-Jan’s thoughts and translated them into spinal cord stimulation to restore voluntary movement,” Grégoire Courtine, a spinal cord specialist at the Swiss Federal Institute of Technology, Lausanne, who helped lead the research, told the press conference. press.
Jocelyne Bloch, a neuroscientist at the University of Lausanne who placed the implant in Mr. Oskam added: “It was quite science fiction at first for me, but it’s become reality today.”
There have been a number of technological advances in the treatment of spinal cord injury in recent decades. In 2016, a group of scientists led by Dr. Courtine managed to restore the ability to walk in paralyzed monkeys, and another helped a man regain control of his crippled hand. In 2018, a different group of scientists, also led by Dr. Courtine, developed a way to stimulate the brain with electrical pulse generators, allowing partially paralyzed people to walk and cycle again. Last year, more advanced brain stimulation procedures allowed paralyzed individuals to swim, walk and cycle in a single day of treatment.
Mr. Oskam underwent stimulation procedures in previous years and even regained some ability to walk, but eventually his improvement stalled. At the press conference, Oskam said that these stimulation technologies left him with the feeling that there was something strange about locomotion, a strange distance between his mind and his body.
The new interface changed that, he said: “The stimulation used to be controlling me and now I’m controlling the stimulation”.
In the new study, the brain-spine interface, as the researchers called it, harnessed an artificial intelligence thought decoder to read Oskam’s intentions — detectable as electrical signals in his brain — and match them to muscle movements. The etiology of natural movement from thought to intention to action has been preserved. The only addition, as Dr. Courtine described, was the digital bridge spanning the injured parts of the spine.
Andrew Jackson, a neuroscientist at the University of Newcastle who was not involved in the study, said: “This raises interesting questions about autonomy and the origin of commands. You keep blurring the philosophical boundary between what the brain is and what technology is.”
The Doctor. Jackson added that scientists in the field had been theorizing about connecting the brain to spinal cord stimulators for decades, but that this represented the first time they had achieved such success in a human patient. “It’s easy to say, it’s much harder to do,” he said.
To achieve this result, the researchers first implanted electrodes in Oskam’s skull and spine. The team then used a machine learning program to observe which parts of his brain lit up as he tried to move different parts of his body. This thought decoder was able to match the activity of certain electrodes to specific intentions: a setting would light up whenever Mr. Oskam was trying to move his ankles, another when he was trying to move his hips.
Then the researchers used another algorithm to connect the brain implant to the spinal implant, which was configured to send electrical signals to different parts of your body, triggering movement. The algorithm was able to take into account small variations in the direction and speed of each muscle contraction and relaxation. And since signals between the brain and the spine were sent every 300 milliseconds, Mr. Oskam could quickly adjust his strategy based on what was working and what wasn’t. In the first treatment session, he may sprain his hip muscles.
Over the next few months, the researchers tweaked the brain-spine interface to better suit basic actions like walking and standing. Mr. Oskam gained a somewhat healthy-looking gait and was able to traverse steps and ramps with relative ease, even after months without treatment. Furthermore, after a year of treatment, he began to notice marked improvements in his movements without the aid of the brain-spine interface. The researchers documented these improvements on weight-bearing, balance, and walking tests.
Now, Mr. Oskam can walk to a limited extent in his house, get in and out of a car and stop at a bar for a drink. For the first time, he said, he feels in control.
The researchers acknowledged limitations in their work. Subtle intentions in the brain are difficult to distinguish, and while the current brain-spine interface is adequate for walking, the same probably cannot be said for restoring upper body movement. The treatment is also invasive, requiring several surgeries and hours of physical therapy. The current system does not correct all spinal cord palsies.
But the team was hopeful that new advances would make the treatment more accessible and systematically effective. “This is our real goal,” said Dr. Courtine, “make this technology available worldwide to all patients who need it.”
