Scientists say they may be on the brink of translating into words the thoughts of a man who can no longer speak, after a pioneering experiment.
Electrodes were planted in the part of the brain which controls speech
Electrodes have been implanted in the brain of Eric Ramsay, who has been "locked in" - conscious but paralysed - since a car crash eight years ago.
These have been recording pulses in areas of the brain involved in speech.
Now, New Scientist magazine reports, they are to use the signals he generates to drive speech software.
Although the data is still being analysed, researchers at Boston University believe they can correctly identify the sound Mr Ramsay's brain is imagining some 80% of the time.
CAUSES OF LOCKED-IN SYNDROME:
Disease which damages nerve cells
In the next few weeks, a computer will start the task of translating his thoughts into sounds.
"We hope it will be a breakthrough," says Joe Wright of Neural Signals, which has helped develop the technology.
"Conversation is what we're hoping for, but we're pretty far from that."
Experts in the field of neuroscience agreed it was an exciting advance.
"It hasn't come completely out of the blue," said Professor Geraint Rees, a neuroscientist at University College London.
"We have been moving towards decoding primitive vocabulary for a while now. But this is certainly an interesting development, although invasive techniques, where something is out in someone's brain, such as these will of course carry risks."
Reading people's minds remains a far-off prospect, however.
"There is a huge difference between a technique like this, which is able to pick up signals the subject wants to be picked up, and being able to delve deep into the mind," says Professor John Dylan Haynes of the Max Planck Institute for Human Cognitive and Brain Sciences.
"It's very exciting that we are starting to be able to translate some basic thoughts, but we are a lot further away from a universal mind reading machine than some people hoped - or feared - we may be five years ago."