by Richard Alleyne
September 08, 2010
A mind reading machine is a
step closer to reality after scientists discovered a way
of translating people's thoughts into words.
machine' can convert thoughts into speech
Photo: GETTY IMAGES
Researchers have been able to translate
brain signals into speech using sensors attached to the surface of
the brain for the first time.
The breakthrough, which is up to 90 per cent accurate, offers a way
to communicate for paralyzed patients who cannot speak and could
eventually lead to being able to read anyone thoughts.
"We were beside ourselves with
excitement when it started working," said Professor Bradley
Greger, a bioengineer at Utah University who led the team of
"It was just one of the moments when everything came together.
"We have been able to decode spoken words using only signals
from the brain with a device that has promise for long-term use
in paralyzed patients who cannot now speak.
"I would call it brain reading and we hope that in two or three
years it will be available for use for paralyzed patients."
The experimental breakthrough came when
the team attached two button sized grids of 16 tiny electrodes to
the speech centers of the brain of an epileptic patient. The sensors
were attached to the surface of the brain The patient had had part
of his skull removed for another operation to treat his condition.
Using the electrodes, the scientists recorded brain signals in a
computer as the patient repeatedly read each of 10 words that might
be useful to a paralyzed person:
yes, no, hot, cold, hungry, thirsty,
hello, goodbye, more and less.
Then they got him to repeat the words to
the computer and it was able to match the brain signals for each
word 76 per cent to 90 per cent of the time. The computer picked up
the patient's brain waves as he talked and did not use any voice
Because just thinking a word - and not saying it - is thought to
produce the same brain signals, Prof Greger and his team
believe that soon they will be able to have translation device and
voice box that repeats the word you are thinking.
What is more, the brains of people who are paralyzed are often
healthy and produce the same signals as those in able bodied people
- it is just they are blocked by injury from reaching the muscle.
The researchers said the method needs improvement, but could lead in
a few years to clinical trials on paralyzed people who cannot speak
due to so-called "locked-in" syndrome.
“This is proof of concept,” Prof
Greger said, “We’ve proven these signals can tell you what the
person is saying well above chance.
"But we need to be able to do more words with more accuracy
before it is something a patient really might find useful.”
People who eventually could benefit from
a wireless device that converts thoughts into computer-spoken
words include those paralyzed by stroke, disease and injury,
Prof Greger said.
People who are now “locked in” often communicate with any movement
they can make - blinking an eye or moving a hand slightly - to
arduously pick letters or words from a list.
The new device would allow them freedom to speak on their own.
"Even if we can just get them 30 or
40 words that could really give them so much better quality of
life," said Prof Greger.
“It doesn’t mean the problem is completely solved and we can all
go home. It means it works, and we now need to refine it so that
people with locked-in syndrome could really communicate.”
The study, published in the journal of
Neural Engineering, used a new kinds of non-penetrating
microelectrodes that sit on the brain without poking into it.
The first was attached to the
face motor cortex, which controls facial movement and is on
the top left hand side of the brain.
The second was attached to the
Wernicke's area, an area just above the left ear that acts
as a sort of language translator for the brain.
Because the microelectrodes do not
penetrate brain matter, they are considered safe to place on speech
areas of the brain - something that cannot be done with penetrating
electrodes that have been used in experimental devices to help
paralyzed people control a computer cursor or an artificial arm.
The researchers were most accurate - 85 per cent - in distinguishing
brain signals for one word from those for another when they used
signals recorded from the facial motor cortex.
They were less accurate - 76 per cent - when using signals from
Last year, Prof Greger and colleagues published a study showing
electrodes could “read” brain signals controlling arm movements.