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Scientists decode words from brain signals, fueling hopes for mind reading


(CBS) Scientists say they've used a computer program to decode a person's brain waves and reconstruct the words a person hears. They think this technology could one day be used to eavesdrop on a person's thoughts.

Sound too invasive? Scientists hope it could one day help people who lose the ability to speak.

"This is huge for patients who have damage to their speech mechanisms because of a stroke or Lou Gehrig's disease and can't speak," Dr. Robert Knight, professor of psychology and neuroscience at UC Berkeley, said in a written statement. "If you could eventually reconstruct imagined conversations from brain activity, thousands of people could benefit."

For the study, published in the Jan. 31 issue of PLoS Biology, the scientists input electrodes into brain surgery patients, and then read them a single word. They tested two computer methods of decoding brain waves, but one method was far superior, they found.

The scientists thought they'd accurately be able to determine the word if they repeated it several times, but even Knight was surprised the program worked so well to pick up words on the first try.

"I didn't think it could possibly work, but Brian did it," Knight said of his graduate student Brian N. Pasley, who lead the research. "His computational model can reproduce the sound the patient heard and you can actually recognize the word, although not at a perfect level."

Pasley told Discovery News the program decodes the brain's perception of sound, sort of like how a piano works.

"If you understand the relationship between the keys and their sounds, you could turn on the TV and watch someone perform with the sound off," he said. "And just by looking at what keys were being pressed, you could understand what sounds were being played."

But don't expect to buy a mind-reader anytime soon. Since the research was based on what a person hears, the principles would have to apply to someone who is imagining speech, the researchers cautioned.

"There is some evidence that perception and imagery may be pretty similar in the brain," Pasley said in the statement. "If you can understand the relationship well enough between the brain recordings and sound, you could either synthesize the actual sound a person is thinking, or just write out the words with a type of interface device."

The bottom line?

"From a prosthetic view, people who have speech disorders... could possibly have a prosthetic device when they can't speak but they can imagine what they want to say," Knight told BBC News. "The patients are giving us this data, so it'd be nice if we gave something back to them eventually."

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