Brain implant brings lasting movement and sensation to man with paralysis
Keith Thomas is experiencing renewed movement and feeling in his hands following an innovative brain-stimulation treatment—and the improvements have continued even without the technology being switched on.
Thomas, 48, became paralysed from the chest down after a diving accident in July 2020. He lost sensation and control in his limbs and experienced considerable muscle wasting. Six years later, his progress is offering researchers an encouraging glimpse of how the nervous system may recover through neuroplasticity, the brain’s ability to create and strengthen neural pathways.
Chad Bouton and his colleagues at the Feinstein Institutes for Medical Research in New York began treating Thomas in 2023. During a double neural bypass procedure, the team implanted five electrodes in areas of his brain involved in movement and sensation.
The electrodes were connected to a computer system that used artificial intelligence to interpret Thomas’s intention to move. Those signals were then transmitted to electronic splints, which stimulated the muscles in his arms, hands and fingers. With this assistance, he was able to perform meaningful everyday actions, including lifting a coffee cup and scratching his face.
The researchers also worked to restore a sense of touch. They placed force sensors inside custom-made, 3D-printed devices worn on Thomas’s hands and fingers. When the sensors detected pressure, electrical signals were sent to the sensory regions of his brain.
The system produced remarkable experimental results, including allowing Thomas to experience sensations from objects touched through another person’s hand. But an unplanned pause in the research revealed something potentially even more hopeful.
The team initially intended to stop stimulation for approximately one month to see whether any benefits remained. A fire in the building extended that interruption to around three months.
“Then we had a fire in the building, and it actually forced us to stop stimulation for even longer than we’d planned, for about three months,” says Bouton.
Rather than losing his progress, Thomas retained strength, sensation and function in his hands throughout the extended break.
“We turned everything off completely, for many months, and yet he’s maintained these gains,” says Bouton. “That’s unheard of.”
Thomas’s control has continued to become more precise. “He’s now also controlling individual fingers with even more accuracy, so that’s big,” says Bouton.
During a video interview, Thomas demonstrated that he could raise his elbows almost as high as his shoulders. He also reported feeling “tingling” in his wrist when pressure was applied, even while he was “unplugged from the computer”.
“When I first felt it, it was amazing,” he says. “I’m used to it now.”
The lasting improvements suggest that the treatment may have helped Thomas’s nervous system reorganise itself. Researchers have also recorded stronger responses in his sensory cortex since the procedure.
Neuroplasticity enables the brain to adapt by forming new neural connections. After a spinal cord injury, this process may strengthen surviving pathways or engage alternative circuits, helping signals travel through networks that were previously unable to produce useful movement.
Sergey Stavisky at the University of California, Davis, says the findings support the idea that the technology could encourage genuine nervous-system recovery rather than simply providing temporary assistance.
“The goal is to help the nervous system partially heal so the person can move their own body better,” he says.
Daniel Lu at the University of California, Los Angeles, believes the continuing benefits may indicate that the intervention is doing more than restoring movement while it is active.
“If these improvements persist even when the system is turned off, then the device is doing more than temporarily restoring function,” says Lu. “It may be helping the nervous system reorganise itself through neuroplasticity.”
“After an injury such as spinal cord injury, those same mechanisms may help restore function by strengthening spared pathways or recruiting alternative circuits, allowing neural signals to travel through networks that were previously too weak to support meaningful movement,” he says.
Although Thomas’s experience is promising, it remains a single case. Researchers do not yet know whether people with other forms of paralysis or different injuries would experience similar results.
Charles Greenspon at the University of Chicago, who has studied stimulation designed to restore touch in people with spinal cord injuries, says responses can vary considerably. Some people benefit more than others, while some show no response.
“And we have no idea why,” he says. “So, the question is: can you replicate it? This is a really ambitious study, but we need to see them replicating their results in more participants before we believe the hype.”
For Thomas and the research team, however, the progress so far provides meaningful reason for optimism.
“At this point now we know nothing’s impossible, or anything’s possible,” says Bouton. “I think it’s possible he will continue to to improve.”
