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Gert-Jan Oskam was living in China in 2011 when a motorcycle accident left him paralyzed from the waist down. Now, with a combination of devices, scientists are giving back control over the lower body.
“For 12 years I have tried to withdraw,” Mr. Oskam said at a press conference on Tuesday. “Now I’ve learned to walk normally, naturally.”
In a study published on Wednesday in the journal Nature, researchers in Switzerland described an implant that provided a “digital bridge” between Mr Oskam’s brain and spinal cord, bypassing the injured part. The invention allowed Mr. Oskam, 40, to stand, walk and climb steep inclines with only the help of a walker. More than a year after the implant, he has retained these abilities and is actually showing signs of neurological recovery, walking with crutches even after the implant is turned off.
“We have captured Gert-Jan’s thoughts, and translated these thoughts 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, said at a press conference .
Jocelyne Bloch, a neurologist at the University of Lausanne who placed the implant in Mr. Oskam, added, “It was science fiction at first for me, but now it’s a reality.”
There have been several advances in spinal cord injury treatment technology in recent decades. In 2016, a group of scientists led by Dr. Courtine was able to restore the ability to walk in paralyzed monkeys, and others helped people control their paralyzed hands. In 2018, a different group of scientists, also led by Dr. Courtine, invented a way to stimulate the brain with an electric pulse generator, allowing partially paralyzed people to walk and ride a bike again. Last year, an advanced brain stimulation procedure allowed paralyzed subjects to swim, walk and cycle within a day of treatment.
Mr. Oskam has undergone stimulation procedures in previous years, and has even regained some of his ability to walk, but his improvement is finally improving. At the press conference, Mr. Oskam said that the stimulation technology made him feel something alien about the locomotive, an alien distance between mind and body.
The new interface changes this, saying: “Stimulation used to control me, and now I control stimulation.”
In the new study, the brain-spine interface, as the researchers called it, took advantage of artificial intelligence thought decoders to read Mr. Oskam’s intentions – detectable as electrical signals in the brain – and match them with muscle movements. The etiology of natural movement, from thought to intention to action, is preserved. In addition, as Dr. Courtine explained that, this is a digital bridge across the injured part of the spine.
Andrew Jackson, a neuroscientist at the University of Newcastle who was not involved in the study, said: “It raises interesting questions about autonomy, and the source of command. You continue to break down the philosophical boundaries between what the brain is and what technology is.
Dr. Jackson added that scientists in the field have been theorizing about connecting the brain to a spinal cord stimulator for decades, but this represents the first time they have had success in a human patient. “Easy to say, harder to do,” he said.
To achieve this result, the researchers first implanted electrodes on Mr. Oskam’s skull and spine. The team then used a machine-learning program to observe which parts of the brain lit up while trying to move different parts of the body. This thought decoder can match specific electrode activities with specific goals: One configuration lights up when Mr. Oskam tries to move his ankles, another when he tries to move his hips.
Then the researchers used another algorithm to connect the brain implant to the spinal implant, which was set up to send electrical signals to different parts of the body, causing movement. The algorithm can account for slight variations in the direction and speed of each muscle contraction and relaxation. And, because signals between the brain and spinal cord are sent every 300 milliseconds, Mr. Oskam can quickly adjust strategies based on what works and what doesn’t. In the first treatment session, he was able to flex his hip muscles.
Over the next few months, the researchers refined the brain-spine interface to better suit basic actions like walking and standing. Mr. Oskam regained a somewhat healthy gait and was able to navigate stairs and ramps with relative ease, even after months without treatment. In addition, after a year in treatment, he began to notice a clear improvement in his movements without the help of a brain-spine interface. Researchers noted these improvements in tests of weight, balance and walking.
Now, Mr. Oskam can walk in a limited way around his house, get in and out of his car and stand at the bar for a drink. At first, he said, he felt like he was in control.
The researchers acknowledge the limitations of their work. Subtle intentions in the brain are difficult to distinguish, and although the brain-spine interface is now suitable for walking, they probably cannot be said to restore upper body movement. The treatment is also invasive, requiring multiple surgeries and hours of physical therapy. The current system does not fix all spinal cord paralysis.
But the team hopes that further progress will make treatment more accessible and more systematically effective. “This is our true goal,” said Dr. Courtine, “to make this technology available worldwide to all patients who need it.”
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