One of the things that makes us human is our ability to communicate. However, a stroke or other medical impairment can take that ability away without warning. Although Stephen Hawking managed to do great things with a computer-aided voice, it took a lot of patience and technology to get there. Composing an e-mail or an utterance for a speech synthesizer using a tongue stick or by blinking can be quite frustrating since most people can only manage about ten words a minute. Conventional speech averages about 150 words per minute. However, scientists recently reported in the journal Nature that they have successfully decoded brain signals into speech directly, which could open up an entirely new world for people who need assistance communicating.
The tech is still only lab-ready, but they claim to be able to produce mostly intelligible sentences using the technique. Previous efforts have only managed to produce single syllables, not entire sentences.
The researchers worked with five people who had electrodes implanted on the surface of their brains as part of epilepsy treatment. Using the existing electrodes, the scientists recorded activity while the subjects read out loud. They also included data on physiological production of sound during speech. Deep learning correlated the brain signals with vocal tract motion and could then map brain patterns to sounds.
The results are not perfect, but 70% of the produced sentences were understood by test subjects — although the subjects had to pick words from a list, not just listen arbitrarily. Oddly, while the results were not quite as good, the process worked even if people read while moving their lips but not making actual sounds.
It appears that the training is specific to the speaker. The paper even says “…in patients with severe paralysis… training data may be very difficult to obtain.” It’s possible that this could limit its usefulness for people who already can’t speak, which coupled with the poor quality of the speech means this work remains unlikey to change anyone’s life in the immediate future. However, it is a great first step to both helping people with speech problems and of course for the dystopian future with that eventual brain interface that will supplant the cell phone.