Paralyzed man walks using 'digital bridge' between brain and spine

Researchers in Switzerland have helped a paralyzed man walk again more than a decade after he was injured.

Gert-Jan Oskam was injured in a cycling accident in 2011 that damaged the spinal cord in his neck, leaving him with paralyzed legs and partially paralyzed arms. Oskam, now 40, has regained some mobility thanks to a new device that creates a "digital bridge" between his brain and the nerves below his injury, according to a study published Wednesday in the journal Nature.

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"For 12 years I've been trying to get back my feet," Oskam, who is from the Netherlands, said during a press briefing earlier this week. "Now I have learned how to walk normal, natural."

The surgical and experimental procedures were performed at Lausanne University Hospital, better known as CHUV, a university hospital in Switzerland. The research team was led by Grégoire Courtine, a neuroscientist at the Swiss Federal Institute of Technology.

The device, called the brain-spine interface, restores communication between Oskam's brain and spine that was interrupted when he was injured. It makes use of a spinal implant that Oskam already has, pairing that with two disc-shaped implants inserted into his skull to hold 64 electrodes against his brain. 

When Oskam thinks about walking, his skull implants detect electrical activity and transmit a signal to a computer Oskam wears in a backpack. Once interpreted by an artificial intelligence thought decoder that reads Oskam's intentions, the information is shared with a spinal pulse generator that stimulates his muscles. 

Oskam was able to voluntarily move his legs and feet after about 40 rehabilitation sessions. He can now stand and walk short distances without the device, using crutches. 

This is the latest technological improvement in spinal cord treatment, but there have been several advancements in recent years. For example, in 2016 Courtine led a team of scientists in successfully restoring the ability to walk in paralyzed monkeys. 

Courtine and his colleagues also led a similar trial in 2018, which demonstrated that a combination of intensive training and electrically stimulating the lower spine could help people with spinal cord injuries walk again. Oskam participated in that trial, but his improvements plateaued after a few years. 

The "digital bridge" builds on Courtine's previous work, giving Oskam more control over the stimulation as opposed to the electrical pulses being pre-programmed. 

"The stimulation before was controlling me and now I am controlling stimulation by my thought," Oskam said. "When I decide to make a step, the (stimulation) will kick in as soon as I think about it."

Oskam's newfound voluntary movement, which was not possible with spinal stimulation alone, suggests that the new device has prompted neurological recovery.

While Oskam is the first participant in the latest trial, researchers are optimistic about future uses for the digital bridge. Courtine's team is now recruiting people to research whether a similar device can restore movement in arms.

"The concept of a digital bridge between the brain and spinal cord augurs a new era in the treatment of motor deficits due to neurological disorders," the research team wrote.