Researchers from Utah University have made a breakthrough in converting brain signals of paralyzed people into words.
"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," said Bradley Greger.
The researchers achieved the feat by using two grids of 16 microelectrodes implanted beneath the skull but atop the brain, in a patient with severe epileptic seizures.
Using the experimental microelectrodes, the scientists recorded brain signals as the patient repeatedly read each of 10 words that might be useful to a paralysed person: yes, no, hot, cold, hungry, thirsty, hello, goodbye, more and less.
When they compared any two signals - such as those generated when the man said the words "yes" and "no" - they were able to distinguish brain signals for each word 76 percent to 90 percent of the time.
The researchers found that each spoken word produced varying brain signals, and thus the pattern of electrodes that most accurately identified each word varied from word to word.
In a more difficult test of distinguishing brain signals for one word from signals for the other nine words, the researchers initially were accurate 28 percent of the time - not good, but better than the 10 percent random chance of accuracy. However, when they focused on signals from the five most accurate electrodes, they identified the correct word almost half (48 percent) of the time.
"It means it works, and we now need to refine it so that people with locked-in syndrome could really communicate," said Greger.
"We can make the grid bigger, have more electrodes and get a tremendous amount of data out of the brain, which probably means more words and better accuracy."