Man with ALS uses a speech BCI independently at home for nearly two years
In Nature Medicine, UC Davis researchers report 99% word accuracy and more than 3,800 hours of home use, including for work, without researchers present.
A study in Nature Medicine shows that a brain-computer interface can let a person with severe paralysis communicate independently at home, day after day, without researchers on hand. The participant is Casey Harrell, 47, who has ALS and was implanted in July 2023 as part of the BrainGate trial.
The results
According to UC Davis, over nearly two years Harrell:
- used the system for more than 3,800 hours,
- communicated over 183,000 sentences (about 2 million words),
- reached 99% word accuracy in controlled tests, at about 56 words per minute, and
- had 92% of his everyday sentences rated accurate or mostly correct.
He uses it to email, browse the web and keep working. The work was led by Nicholas Card, with David Brandman and Sergey Stavisky as senior authors, together with Brown University and Mass General Brigham.
Why it matters
Earlier speech neuroprostheses proved what was possible in research sessions. This study shows sustained, real-world use in one person’s daily life, a key requirement before such devices can become approved medical products. The findings come from a single participant, so wider studies are still needed.
Learn more: Neural decoding · Microelectrode array · UC Davis Neuroprosthetics Lab