With electronics in his brain and spine, a paralyzed man takes a stride

Scientists and neurosurgeons have implanted electronic devices into the brain and spinal cord of a paralyzed man that communicate wirelessly, enhancing his ability to walk and enabling him to climb stairs, according to a study published Wednesday in Nature.

The work fuses two experimental technologies being developed to treat paralysis. One device is inserted into the skull and rests above the brain’s surface, decoding patterns involved in walking and transmitting a signal to a second device implanted along the spinal cord. Electrodes then stimulate the spinal cord in a precise sequence to activate leg muscles needed to walk.

“We have created a wireless interface between the brain and the spinal cord using brain-computer interface technology that transforms thought into action,” Grégoire Courtine, an author of the paper, said in a statement.

Such science fiction-like achievements are becoming more common as scientists, brain surgeons and engineers accelerate research to connect brains with computers. By linking into the central nervous system, such devices can run commands that people with paralysis can no longer execute unassisted, enabling them to type or raise a paralyzed fist by thinking about it. The study in Nature marries spinal stimulation with what is known as brain-computer interface, a field popularized by Elon Musk and his brain-implant company, Neuralink.

Companies developing this technology say the first applications will be for people who have lost the ability to move or communicate, although it also raises the long-term prospect of enhancing the abilities of healthy people. Musk has spoken of brain implants as a way for humans to keep up with the advances of artificial intelligence, and the field is drawing the attention of bioethicists, government regulators and investors.

The single patient in the Nature paper is a 40-year-old Dutchman named Gert-Jan, who was paralyzed in a cycling accident. He received an experimental spinal-cord stimulator in 2017 that restored his ability to walk, but the subsequent brain implant gave him much greater control, according to Dave Marver, the chief executive of Onward Medical, the Netherlands-based company that makes the spinal-cord device.

“The incorporation of the brain-computer interface allows even more natural movement than our spinal cord stimulation does alone,” Marver said. Gert-Jan can now pause mid-gait, adjust his stride and navigate irregular terrain such as stairs.

In video made available by the researchers, Gert-Jan can be seen bracing himself on a walker, bending his knees, lifting his legs and striding in a slow but smooth motion beside a canal.

Onward Medical’s device was previously used in research that restored the ability to walk to nine patients, mapping the neurons associated with the body’s complex commands for walking. The brain implant used in the study was developed by a French company, Clinatec, and a French government-backed research institute called CEA. It employs a device that rests atop the brain rather than penetrating into it.

Marver said the company probably is five years away from being able to commercialize a system like the one used in the Nature study, but his aspirations are much broader. “Ultimately, our vision is that a person with paralysis will be able to visit the doctor and select what function they want to restore,” he said.