Man with ALS used a speech brain–computer interface at home for nearly two years without researchers present

What happened

A man with paralysis and severe dysarthria caused by amyotrophic lateral sclerosis used an implanted brain–computer interface on his own, almost daily, for nearly two years. The system combined a brain-to-text speech decoder with a cursor decoder.

Over that period he used it for more than 3,800 hours at home with no researchers present. He communicated 183,060 sentences, a total of 1,960,163 words, at an average of 56 words per minute, and labelled 92% of sentences as decoded at least mostly correctly. In formal tests where he was asked to say words shown on a screen, his attempted speech was decoded with more than 99% word accuracy from a 125,000-word vocabulary. He used the speech decoder as a keyboard and the cursor decoder as a mouse to send messages and emails and browse the internet, and he kept full-time employment.

Why it matters

Earlier studies showed that speech can be decoded accurately from the cortex, but in sessions run by researchers. Two things needed for a practical device had not been shown: operation at home without technical help, and performance that holds up over years. This study reports both in one person.

Caveats

This is a single participant, so it does not show how often such results can be achieved. The 92% figure is the participant's own rating of everyday use, not a measured accuracy. The paper's title says the device is intracortical, which requires brain surgery; this entry is based on the abstract, which does not report adverse events.