U.S. researchers say they've translated brain signals into words, a step toward allowing severely paralyzed people to use their thoughts to "talk."

University of Utah scientists translated signals generated by the brain into words using grids of micro-electrodes implanted beneath the skull but atop the brain, a university release said Monday.

"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," Bradley Greger, an assistant professor of bioengineering, said.

The study used a new kind of non-penetrating micro-electrode that sits on the brain without poking into it. Because the micro-electrodes do not penetrate brain matter, they are considered safe to place on speech areas of the brain.

The scientists placed grids of tiny micro-electrodes over speech centers in the brain of a volunteer with severe epileptic seizures. Using the micro-electrodes, the scientists recorded brain signals 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.

When they compared any two brain signals, such as those generated as the volunteer said the words "yes" and "no," they were able to distinguish brain signals for each word 76 percent to 90 percent of the time.

People who eventually could benefit from a wireless device that converts thoughts into computer-spoken spoken words include those paralyzed by stroke, Lou Gehrig's disease and trauma, Greger said.