Showing posts with label Lou Gherigs Disease. Show all posts
Showing posts with label Lou Gherigs Disease. Show all posts

Jan 23, 2010

Thoughts to Speech

Scientists have successfully tested a system that translates brain waves into speech, raising the prospect that people left mute by stroke, Lou Gehrig's disease and other afflictions will one day be able to communicate by synthetic voice.

The system was tested on a 26-year-old man left paralyzed by a brain stem stroke, but with his consciousness and cognitive abilities intact. The condition is known as "locked-in syndrome." In this condition, communication by eye movement or other limited motion is possible, but extremely cumbersome.

Scientists implanted an electrode about 5 millimeters deep into the part of the subject's brain responsible for planning speech. After a few months nerve cells grew into the electrode, producing detectable signals. It took several years, however, to develop a computer system that could discriminate elements of speech from the busy backdrop of neural activity.

The first "words" detected from the subject's brain were three vowel sounds, but the speed with which the speech thought was transmitted into audible sound was about 50 milliseconds -- the same amount of time it typically takes for naturally occurring speech.

The embedded electrode amplifies neural signals and converts them into FM radio waves which are then transmitted wirelessly across the subject's scalp to two coils on his head that serve as receiving antennas. The signals are then routed into a system that digitizes, sorts and decodes them. The results are fed into a program on a PC that synthesizes speech.