Researchers have restored hand movement and the sense of touch to a man paralysed from the chest down. The results, published in Nature Medicine, suggest the technology partly rewired his nervous system.
The system, called a “double neural bypass,” comes from the Feinstein Institutes for Medical Research, the research arm of Northwell Health, the team said. It combines a brain-computer interface, AI, and electrical stimulation of the spinal cord and brain.
What the participant regained
The participant, Keith Thomas, broke his neck in a 2020 diving accident. He had complete tetraplegia and could not lift his hands to his face. He enrolled in the three-year trial 13 months later.
After training, Thomas could feed himself and drink from a cup with his own hand. Over 35 weeks, his right arm grew 86% stronger and his left 62% stronger, the researchers reported. He could also scratch his nose and wipe his mouth unaided.
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A separate technique, called cortical mirroring, targeted touch. After about 25 weeks, Thomas regained feeling in a wrist that had been numb since his injury.
Why the lasting effect matters
Many gains held after the stimulation stopped. On a recent follow-up, they were still present more than two years later. The team says this points to real rewiring, or neuroplasticity, rather than a temporary assist.
“We're not just bypassing the injury; we're actually rewiring the nervous system,” said Chad Bouton, the study's corresponding author, in a statement. “For me this is an incredible moment,” he told the Guardian.
“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,” Thomas said.
How it works
Surgeons implanted five microelectrode arrays in Thomas's brain during a 15-hour operation. AI decodes his movement intentions and stimulates his forearm muscles to move his own hand. Sensors in a 3D-printed brace then trigger stimulation of the sensory cortex to create the feeling of touch.
The decoder held up to 84.6% accuracy over five months without retraining. Thomas could lift empty eggshells without breaking them 87% of the time, even while holding a conversation.
The wider field
The work joins a fast-moving field of brain-computer interfaces. Rivals have used implants to restore speech, while others chase wearable or non-invasive approaches, and China has cleared its first commercial brain implant.
About 15 million people live with spinal cord injury worldwide, and most with tetraplegia rank hand function as their top priority. The team plans larger trials and is testing the system for other conditions, including stroke.