By July 2023, Casey Harrell, then age 45, had lost the ability to speak to his then four-year-old daughter. The neurodegenerative disorder amyotrophic lateral sclerosis (ALS) had gradually paralyzed him in the five years since his symptoms began. As the effects spread to the lips, tongue and jaw, his speech devolved into indistinct sounds that his daughter could not understand.

But a month after a surgery in which Harrell had four 3-by-3 millimeter arrays of electrodes implanted in his brain that July, he was suddenly able to tell his little girl whatever he wanted. The electrodes picked up the chatter of neurons responsible for articulating word sounds, or phonemes, while other parts of a novel brain-computer interface (BCI) translated that chatter into clear synthetic speech.

“She hadn’t had the ability to communicate very much with me for about two years. Now that is very different,” Harrell says, speaking through the device a year after the surgery. “I can help her mother to parent her. I can have a deeper relationship with her and tell her what I am thinking.”...   Source