In 2023, neurologists at the Feinstein Institutes for Medical Research in New York achieved a medical breakthrough that many experts believed was once impossible. After 15-hours of open-brain surgery, a team of specialists successfully completed the first “double neural bypass” procedure, and installed and virtually mapped a brain-computer interface (BCI) for a man named Keith Thomas living with quadriplegia. As Thomas slowly regained feeling and strength in his arm and wrist, the monumental advancement made international headlines and was inducted into TIME Magazine’s Best Inventions Hall of Fame.
“There was a time that I didn’t know if I was even going to live, or if I wanted to, frankly. And now, I can feel the touch of someone holding my hand. It’s overwhelming,” Thomas said four months after the initial surgery.
Double neural bypass: Man living with paralysis has feeling, lasting movement restored in arm & hand
Nearly three years later, the pioneers behind the double neural bypass have offered updates on their findings and Thomas’ progress. As they detail in a study published today in the journal Nature Medicine, the combination of BCI and artificial intelligence technologies continues to provide their patient with lasting, life-changing recovery in their limb. By rerouting the nervous system’s neural pathways, Thomas can now feed himself and drink from a cup using restored feeling in his hand, and has gained increased both his arm strength and wrist sensation.
“This approach is a new way to treat severe paralysis—we’re not just bypassing the injury, we’re actually rewiring the nervous system,” Chad Bouton, a bioelectronic medical specialist and study co-author, said in a statement.
The system relies on five microelectrode arrays surgically installed in Thomas’ brain, which machine learning algorithms then interpret brain signals denoting movement with nearly 85 percent accuracy. Those neural messages are then translated into electrical stimulation patterns given to the forearm muscles, which move as intended. Meanwhile, sensors inside a 3D-printed limb brace that measures grasping pressure. This then creates electrical stimulation in the sensory cortex to generate the perception of touch.
The results are so effective that Thomas is now able to grab and lift hollow eggshells without breaking them nearly 90 percent of the time. He can also perform this and similarly calculated tasks while talking—a vast improvement compared to existing BCI systems when handling cognitive burdens.
First Human Avatar BBI Linking Mind and Body in Two People with Paralysis
“Being able to feel my sister’s hand, to pet my dog and feel her fur— these experiences that the injury took away have been restored. “But beyond the study sessions, I can now scratch my face, wipe my eyes independently,” Thomas said. “The technology has given me back both connection and sense of self.”
“This research holds promise for millions of patients, opening up potential for future research and practical clinical applications that could help hundreds of thousands of people living with paralysis,” said Bouton.
Moving forward, the team is working to improve their system while expanding clinical trials to include other patients with differing levels of spinal injuries and neurological conditions. Recently, they tested the first interhuman neural bypass, which allowed Thomas to feel sensations from another patient as they touched multiple objects.
“We’re not just bypassing the injury, we’re actually rewiring the nervous system,” Bouton added.
