This Implant Turns Brain Waves Into Words: A brain-computer interface deciphers commands intended for the vocal tract

A computer screen shows the question “Would you like some water?” Underneath, three dots blink, followed by words that appear, one at a time: “No I am not thirsty.” • It was brain activity that made those words materialize—the brain of a man who has not spoken for more than 15 years, ever since a stroke damaged the connection between his brain and the rest of his body, leaving him mostly paralyzed. He has used many other technologies to communicate; most recently, he used a pointer attached to his baseball cap to tap out words on a touch screen, a method that was effective but slow. He volunteered for my research group's clinical trial at the University of California, San Francisco in hopes of pioneering a faster method. So far, he has used the brain-to-text system only during research sessions, but he wants to help develop the technology into something that people like himself could use in their everyday lives.