The system was developed in Switzerland by EPFL’s Prof. Grégoire Courtine, and Lausanne University Hospital (CHUV) neuroscientist Prof. Jocelyne Bloch. The Engineer reported on the innovation in 2018, when it first enabled a patient with paralysis caused by a partial spinal cord injury to get up from his wheelchair and walk.
Now, the team has revealed enhancements to the system through more sophisticated implants controlled by artificial intelligence (AI) software.
The implants can simulate the region of the spinal cord that activates the trunk and leg muscles. Thanks to the new technology, described this week in Nature Medicine, Courtine said that three patients with complete spinal cord injury were able to stand, walk, pedal, swim and control their torso movements in just one day after implants were activated.
“Our stimulation algorithms are still based on imitating nature,” said Courtine. “And our new, soft implanted leads are designed to be placed underneath the vertebrae, directly on the spinal cord. They can modulate the neurons regulating specific muscle groups.”
By controlling the implants, Courtine explained that the system can activate the spinal cord like the brain would do naturally.
“Our breakthrough here is the longer, wider implanted leads with electrodes arranged in a way that corresponds exactly to the spinal nerve roots,” said Bloch. “That gives us precise control over the neurons regulating specific muscles.”
This ultimately allows for greater selectivity and accuracy in controlling the motor sequences for a given activity, the team said.
Because the technology is miniaturised, patients can perform their training exercises outdoors and not only inside a lab. Last December, scientists from Courtine and Bloch’s NeuroRestore research centre helped Italian patient Michel Roccati to try the enhanced system outdoors in central Lausanne.
They attached two small remote controls to Roccati’s walker and connected them wirelessly to a tablet that forwards the signals to a pacemaker in Roccati’s abdomen. The pacemaker relays signals to the new lead, implanted on his spinal cord through a surgical procedure, that stimulated specific neurons allowing him to move.
After several months, all three patients followed a training regimen based on the stimulation programmes and were able to regain muscle mass, move around more independently, and take part in social activities like having a drink standing at a bar.
Courtine said that the team is now working with ONWARD Medical to develop treatments for thousands of people around the world.