Washington, Apr 25 : Taking a revolutionary step towards modern communication technologies, a doctoral student posted a status update on the social networking Web site Twitter - only by thinking about it.

Adam Wilson's message-"using EEG to send tweet"- just 23 characters long, demonstrated a natural, manageable way in which "locked-in" patients can couple brain-computer interface technologies with modern communication tools.

Wilson, from University of Wisconsin-Madison biomedical engineering doctoral student, is among a growing group of researchers worldwide who aim to perfect a communication system for users whose bodies do not work, but whose brains function normally.

Such people include those having amyotrophic lateral sclerosis (ALS), brain-stem stroke or high spinal cord injury.

There are brain-computer interface systems that employ an electrode-studded cap wired to a computer, in which the electrodes detect electrical signals in the brain - essentially, thoughts - and translate them into physical actions, such as a cursor motion on a computer screen.

"We started thinking that moving a cursor on a screen is a good scientific exercise. But when we talk to people who have locked-in syndrome or a spinal-cord injury, their No. 1 concern is communication," said Justin Williams, a UW-Madison assistant professor of biomedical engineering and Wilson's adviser.

Based on brain activity related to changes in an object on screen, the researchers embarked upon developing a simple, elegant communication interface.

Essentially, the interface consists of a keyboard displayed on a computer screen.

"The way this works is that all the letters come up, and each one of them flashes individually. And what your brain does is, if you're looking at the `R' on the screen and all the other letters are flashing, nothing happens. But when the `R' flashes, your brain says, `Hey, wait a minute. Something's different about what I was just paying attention to.' And you see a momentary change in brain activity," said the researchers of the study.

Wilson, who used the interface to post the Twitter update, has compared it to texting on a cell phone.

"You have to press a button four times to get the character you want. So this is kind of a slow process at first," he said of texting.

However, as with texting, users improve as they practice using the interface.

"I've seen people do up to eight characters per minute," said Wilson. (ANI)