December 3, 2023

Gert-Jan Oskam was living in China in 2011 when he was involved in a motorcycle accident that left him paralyzed from the hips down. Now, through a series of devices, scientists have given him back control of his lower body.

“For 12 years, I’ve been trying to get my feet on the ground,” Mr Oskarm said at a news conference on Tuesday. “Now I’ve learned how to walk normally and naturally.”

in a study Published in the journal Nature on Wednesday, Swiss researchers described the implant, which provided a “digital bridge” between Mr Oskam’s brain and spinal cord, bypassing the injured part. The discovery allowed Mr Oskam, 40, to stand, walk and climb steep inclines with the help of a walker. More than a year after the implants, he still retains these abilities and has actually shown signs of neurological recovery, walking with a cane even when the implants are off.

“We captured Gert-Jan’s ideas and translated them into stimulation of the spinal cord to re-establish voluntary movement,” said Grégoire Courtine, a spinal cord specialist at the Swiss Federal Institute of Technology in Lausanne who helped lead the study, in a news release. Said at the meeting.

Jocelyne Bloch, a neuroscientist at the University of Lausanne who put the implant into Mr Oskam, added: “At first it was all science fiction for me, but today it is reality.”

In recent decades, many advances have been made in the treatment of spinal cord injury. In 2016, a team of scientists led by Dr Kurtin restored the ability to walk to a paralyzed monkey, while another team helped a man regain control of his paralyzed hand. In 2018, another group of scientists, also led by Dr. Courtine, devised a method stimulate the brain Using electrical pulse generators to allow partially paralyzed people to walk and ride bicycles again. last year, More advanced The brain stimulation procedure allowed the paralyzed subjects to swim, walk and cycle during the day of treatment.

Mr Oskarm had undergone stimulation surgery in previous years and even regained some walking ability, but eventually his progress leveled off. At a news conference, Mr. Oskam said the stimulation techniques made the movement feel strange to him, and that there was an alien distance between his mind and his body.

The new interface changes that, he says: “Before the stimulus controlled me, now I control the stimulus.”

In the new study, which the researchers call a brain-spine interface, it uses an artificial intelligence mind decoder to read Mr. Oskam’s intentions — which can be detected by electrical signals in his brain — and link them to muscles. Movement to match. The etiology of natural movement, from thought to intention to action, is preserved. The only addition, as Dr. Courtine describes it, is a digital bridge across the injured part of the spine.

“It raises interesting questions about the source of autonomy and command,” said Andrew Jackson, a neuroscientist at Newcastle University who was not involved in the study. “You continue to blur the philosophical line between what is a brain and what is technology.”

Dr Jackson added that scientists in the field have been working on the theory of connecting the brain to spinal cord stimulators for decades, but this is the first time they have been so successful in human patients. “That’s easier said than done,” he said.

To achieve this result, the researchers first implanted electrodes in Mr. Oskam’s skull and spine. The team then used a machine learning program to see which parts of the brain lit up when he tried to move different parts of his body. This mind decoder is able to match the activity of specific electrodes with specific intentions: Whenever Mr. Oskam tries to move his ankle, one configuration lights up, and when he tries to move his hip, another configuration lights up. lights up.

The researchers then used another algorithm to connect the brain implant to the spinal implant, which was programmed to send electrical signals to different parts of his body, inducing movement. The algorithm is able to account for subtle changes in the direction and speed of each muscle’s contraction and relaxation. And, because signals between the brain and spine are sent every 300 milliseconds, Mr. Oskam can quickly adjust his strategy based on what’s working and what’s not. During the first session, he was able to twist his hip muscles.

Over the next few months, the researchers fine-tuned the brain-spine interface to better accommodate basic movements like walking and standing. Mr. Oskam’s gait appeared somewhat healthy, and he was able to traverse steps and slopes with relative ease, even after going without treatment for several months. Additionally, after a year of treatment, he began to notice significant improvements in his movement without the help of a brain-spine interface. The researchers documented these improvements in weight bearing, balance and walking tests.

Now, Mr Oskam can walk in limited fashion around his house, get in and out of cars, and stand at the bar for a drink. For the first time, he said, he felt like he was in control.

The researchers acknowledge the limitations of their work. Fine-grained intentions in the brain are hard to discern, and current brain-spine interfaces, while fine for walking, might not be good for restoring upper-body motion. The treatment is also invasive, requiring multiple surgeries and hours of physical therapy. The current system does not fix all spinal palsies.

But the team hopes that further advances will make the treatment more accessible and more systematically effective. “That’s our real goal,” said Dr. Courtine, “to make this technology available to every patient in the world who needs it.”

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