Scientists have developed a brain implant that can read people’s minds and turn their thoughts to speech.
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They add that their findings, published in the journal Nature, could help people when disease robs them of their ability to talk.
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The mind-reading technology works in two stages.
First an electrode is implanted in the brain to pick up the electrical signals that manoeuvre the lips, tongue, voice box and jaw.
Then powerful computing is used to simulate how the movements in the mouth and throat would form different sounds.
This results in synthesised speech coming out of a “virtual vocal tract”.
Why do it like that?
You might think it would be easier to scour the brain for the pattern of electrical signals that code for each word.
However, attempts to do so have only had limited success.
Instead it was focusing on the shape of the mouth and the sounds it would produce that allowed the scientists to achieve a world first.
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It is not perfect.
If you listen to this recording of synthesised speech:
Media captionListen to speech decoded from brain activity
You can tell it is not crystal clear (the recording says “the proof you are seeking is not available in books”).
The system is better with prolonged sounds like the “sh” in ship than with abrupt sounds such as the “buh” sound in “books”.
In experiments with five people, who read hundreds of sentences, listeners were able to discern what was being spoken up to 70% of the time when they were given a list of words to choose from.
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The participants in the study were told not to make any specific mouth movements.
Prof Chang said: “There were just asked to do the very simple thing of reading some sentences.
“So it’s a very natural act that the brain translates into movements itself.”
