An experimental brain implant that translates brain signals into words has been a success, say researchers in California.
It’s a major step towards the development of a technology that could help people communicate by thinking, potentially changing the lives of those who lose the ability to speak through injury or illness.
Scientists at the University of California, San Francisco, worked with a man in his 30s who suffered a paralysing stroke more than 15 years ago and lost the ability to speak, reports the Wall Street Journal. He agreed to have electrodes surgically attached to the outer surface of his brain to test the neuroprosthesis.
The experiment was detailed in a paper published in the New England Journal of Medicine. Over the course of 50 separate sessions, the researchers recorded the man’s brain activity as he observed words displayed on a screen and imagined saying them aloud.
The researchers said they could identify the word the man was saying almost half the time, which rose to 76% when the scientists incorporated word-prediction algorithms.
“To our knowledge, this is the first successful demonstration of direct decoding of full words from the brain activity of someone who is paralyzed and cannot speak,” said neurosurgeon Dr. Eddie Chang, the paper’s senior author. “It shows strong promise to restore communication by tapping into the brain’s natural speech machinery.”
Experts say the high error rate, limited vocabulary – this study used just 50 words – and the time it takes to train the system to recognise imagined words mean there’s still a long way to go before the technology could be used practically in the real world.
However, the experiment has shown that the brain region responsible for speech continues to function even years after the ability to speak has been lost and that computers can be taught to decode full words from brain activity.
