Thoughts became words: how a brain implant gave him back his life

Casey Harrell, a 48-year-old man in Oakland living with ALS, regained the ability to communicate after surgeons implanted 256 microelectrodes in 2023 to capture brain activity tied to speech. Using a system that converts neural signals into text on a screen at an average pace of 56 words per minute, Harrell can now send messages, write emails, and continue climate advocacy work. A built-in voice synthesizer reads his sentences aloud using a reconstructed voice from recordings made before his illness. In a Nature Medicine report, over 397 days he activated the device 364 times, producing 183,060 phrases with 92% partially decoded, and also controls a computer cursor via hand-related signals.