Keith Thomas, a 48-year-old man from Massapequa, New York, who was paralysed from the chest down in a swimming accident six years ago, has regained the ability to feed himself and drink from a cup thanks to a brain implant that bypasses his spinal cord injury.
Breakthrough in brain-computer interface
Thomas could not lift his arms off his wheelchair when he agreed to trial the technology in 2021. After surgery to implant electrodes in his brain and months of training, he can now move his arms and hands and feel the sensation of touch. Researchers at the Feinstein Institutes for Medical Research, the research arm of Northwell Health, fitted Thomas with a brain-computer interface that not only helps him move his limbs but also sends signals back to his brain to recreate touch.
Remarkably, the technology appears to have partly rewired Thomas's nervous system, restoring some hand functions and sensations that persist even when the system is switched off. "For me this is an incredible moment," said Prof Chad Bouton, who led the development. "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."
Clinical trial and results
Thomas was 42 when he broke his neck diving into a swimming pool in July 2020. He blacked out and regained consciousness to see a helicopter on the front lawn. "The next day I couldn't even move," he said. In October 2021, he joined a three-year clinical trial of what researchers call a "double neural bypass". Electrodes implanted in his brain detect when he wants to move his arms, and signals are routed to his arms and hands. Simultaneously, pressure sensors on his hand, fingers, and thumb detect contact with objects and send signals back to his brain to simulate touch.
Writing in Nature Medicine, the researchers describe Thomas's progress after 35 weeks of training. 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, he can now independently scratch his nose and wipe his face. The system also allowed him to handle delicate items such as egg shells.
Cortical mirroring enhances sensation
The researchers developed 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 the same patterns. Simultaneously, they 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. "In a recent follow up, it was found these gains were still present after more than two years," said Bouton. "This is incredibly encouraging."
It is unclear how much function and sensation the technology can restore to paralysed limbs, and trials involving more patients are needed to see how well it works for different spinal cord injuries. Bouton added: "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."
