ALS patient becomes long-term home user of a speech brain implant
A man with ALS has become what researchers call the first “power user” of a speech brain-computer interface , using the device on his own at home rather than only in supervised lab sessions. Casey Harrell, 45, has four 64-electrode arrays implanted in his speech motor cortex; a UC Davis team led by David Brandman built software that decodes his attempted speech into phonemes and then words at roughly 97.5% accuracy across a 125,000-word vocabulary. Over about 22 months he logged more than 3,800 hours of independent use, emailing, texting and continuing his work as an environmental activist.
The notable result is less the accuracy than the durability and autonomy. Implanted electrodes have historically lost signal as scar tissue builds, and most demonstrations depend on a research team being present; Harrell’s system has kept working for three years with minimal involvement from the lab. The researchers caution that the findings come from a single participant and may not generalize — some users have lost function as their disease progressed, and the need for invasive surgery and hospital time will limit who pursues it. Still, sustained at-home use moves speech BCIs a step from proof-of-concept toward an assistive tool people can rely on day to day.