Double Neural Bypass Brain Implant Restores Movement and Sensation in Man with Quadriplegia
核心洞察
A brain-computer interface called the "double neural bypass" enabled a man paralyzed from the chest down to feed himself, drink from a cup, and regain the sensation of touch.
After 35 weeks of training, the patient's right arm strength increased 86% and left arm strength increased 62%, with lasting improvements persisting over two years.
The system routes movement signals from the brain to the limbs while simultaneously sending sensory feedback from pressure sensors back to the brain, completing a bidirectional circuit.
A man who was paralyzed from the chest down following a swimming accident has regained the ability to feed himself, drink from a cup, and feel the fur of his pet dog, thanks to an experimental brain-computer interface developed by researchers at the Feinstein Institutes for Medical Research (搜索), the research arm of Northwell Health.
Keith Thomas of Massapequa, New York, was 42 when he broke his neck diving into a swimming pool in July 2020. The injury left him with virtually no ability to move or feel his limbs below his neck. In October 2021, he enrolled in a three-year clinical trial testing what researchers call a "double neural bypass" — a system designed to bridge the communication gap between his brain and body caused by spinal cord injury (搜索).
Writing in Nature Medicine, the researchers describe Thomas's progress after training with the system for 35 weeks. The strength in his right arm increased 86%, while his left arm was 62% stronger. Having been unable to lift his hands to his face at the start of the trial, Thomas could now independently scratch his nose and wipe his face.
"For me this is an incredible moment," said Prof Chad Bouton, whose team developed the technology. "For years, we have been wanting to really tackle the restoration of movement and the sense of touch and bring those together and we've also wanted to create lasting effects."
How the Double Neural Bypass Works
The system uses electrodes implanted into Thomas's brain to detect neural signals associated with his intention to move his arms. These signals are decoded and routed to his arms and hands, triggering the intended movements. Simultaneously, pressure sensors placed on his hand, fingers, and thumb detect contact with objects and send signals back to his brain, simulating the sensation of touch.
This bidirectional communication completes a circuit: the brain requests movement, the movement is achieved, and sensory feedback confirms the result. In tests, the system allowed Thomas to handle even delicate items such as egg shells.
Cortical Mirroring and Sensory Restoration
The researchers went on to develop a technique called cortical mirroring to improve Thomas's sense of touch. They recorded his brain activity while he imagined being touched and then stimulated sensory regions of his brain with those same patterns. While doing so, they simultaneously stimulated his skin and spinal cord.
After 25 weeks of therapy targeting his right wrist, Thomas regained the sense of touch in a region that had been numb since his accident. He has since been able to feel his sister's hand and the fur on his pet dog, Bow.
Lasting Effects Beyond the Device
Remarkably, the technology appears to have partly rewired Thomas's nervous system, helping to restore some hand functions and sensations that persist even when the system is switched off.
"In a recent follow up, it was found these gains were still present after more than two years," said Bouton. "This is incredibly encouraging."
The researchers believe the approach could have broad applicability. "I think we're going to continue to see progress and I think it'll be applicable to the millions of folks around the world who really need this technology," Bouton added.
It remains unclear how much function and sensation the technology can ultimately restore to paralyzed limbs, and trials involving more patients are needed to assess how well it works for individuals with different types of spinal cord injuries.