In 2023, neurologists at the Feinstein Institutes for Medical Research in New York achieved a medical breakthrough that many experts believed was previously impossible. After 15 hours of open brain surgery, a team of specialists successfully completed the first-ever “neural double bypass” procedure and virtually installed and mapped a brain-computer interface (BCI) for a man named Keith Thomas who lives with quadriplegia. As Thomas slowly regained feeling and strength in his arm and wrist, the monumental breakthrough made international headlines and was included in TIME MagazineHall of fame of the best inventions.

“There was a time when I didn’t even know if I was 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 recovers sensation and lasting movement in arm and hand

Nearly three years later, the pioneers behind double neural bypass have offered updates on their findings and Thomas’s progress. As detailed in a study published today in the journal Nature medicineThe combination of BCI and artificial intelligence technologies continues to provide its patients with a life-changing, long-lasting recovery of their limb. By redirecting neural pathways in the nervous system, Thomas can now feed and drink from a cup using restored sensation in his hand, and has gained greater arm strength and sensation in his wrist.

“This approach is a new way to treat severe paralysis: we are not only avoiding injury, but we are actually rewiring the nervous system,” Chad Bouton, a bioelectronic medicine specialist and co-author of the study, said in a statement.

The system is based on five sets of microelectrodes surgically installed in Thomas’s brain, whose machine learning algorithms interpret brain signals denoting movement with nearly 85 percent accuracy. Those neural messages are then translated into patterns of electrical stimulation that are delivered to the forearm muscles, which move as intended. Meanwhile, sensors inside a 3D-printed brace that measure grip pressure. This then creates electrical stimulation in the sensory cortex to generate the perception of touch.

The results are so effective that Thomas can now grasp and lift hollow eggshells without breaking them almost 90 percent of the time. It can also perform this and other similarly computed tasks while speaking – a huge improvement over existing BCI systems when handling cognitive loads.

The first BBI human avatar that links the mind and body in two people with paralysis

“Being able to feel my sister’s hand, pet my dog ​​and feel her fur – these experiences that the injury took away from me have come back. But beyond the study sessions, I can now scratch my face and wipe my eyes independently,” Thomas said. “Technology has given me back both connection and sense of self.”

“This research holds promise for millions of patients and opens up potential for future research and practical clinical applications that could help hundreds of thousands of people living with paralysis,” Bouton said.

Going forward, the team is working to improve their system while expanding clinical trials to include other patients with different levels of spinal injuries and neurological conditions. Recently, they tested the first interhuman neural bypass, which allowed Thomas to feel sensations from another patient when he touched multiple objects.

“Not only are we preventing injury, we are actually rewiring the nervous system,” Bouton added.

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