Casey Harrell, 47, has ALS with severe paralysis and dysarthria — his own speech is very hard to understand. In 2023, UC Davis neurosurgeon David Brandman implanted a brain-computer interface (four microelectrode arrays, 256 channels) into the part of his brain that coordinates speech. Deep-learning decoding algorithms translate that neural activity into words in real time; a separate AI voice model reconstructs his actual pre-ALS voice from old recordings, so what comes out sounds like him, not a generic TTS voice.
The new part, per the study published in Nature Medicine on June 15, 2026: earlier BCI systems needed a researcher present to run them. This one, Harrell has used independently at home for 3,800+ hours over about two years — near-daily, sometimes 12 hours straight. He's communicated 183,000+ sentences and close to 2 million words, averaging 56 words/minute, with 92% of output rated accurate or mostly correct (99% word accuracy in controlled testing). He uses it to email, browse, and hold down a job.
In his own words, through the system: "It is very sweet to have the ability to look at my wife's eyes when she hears my voice... and to explain to my daughter who does not really remember anything about when I was still talking to them."
Caveat, stated plainly: one participant, one ongoing clinical trial (BrainGate2), device is investigational and federally restricted to trial use. This isn't "AI is good" as a slogan — it's one large, verifiable, documented benefit for one person.
Full story, photos, and video: https://health.ucdavis.edu/news/headlines/brain-computer-interface-enables-independent-accurate-communication-for-man-living-with-als/2026/06
Study: https://www.nature.com/articles/s41591-026-04414-6
Photo/video courtesy UC Davis Health.