Researchers use brain interface to post ...( MADISON In early April Adam Wilson ...)

MADISON In early April, Adam Wilson posted a status update on the social networking Web site Twitter just by thinking about it.

Just 23 characters long, his message, "using EEG to send tweet," demonstrates a natural, manageable way in which "locked-in" patients can couple brain-computer interface technologies with modern communication tools.

A University of Wisconsin-Madison biomedical engineering doctoral student, Wilson 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. Among those are people who have amyotrophic lateral sclerosis (ALS), brain-stem stroke or high spinal cord injury.

Some brain-computer interface systems employ an electrode-studded cap wired to a computer. 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," says Justin Williams, a UW-Madison assistant professor of biomedical engineering and Wilson's adviser. "But when we talk to people who have locked-in syndrome or a spinal-cord injury, their No. 1 concern is communication."

In collaboration with research scientist Gerwin Schalk and colleagues at the Wadsworth Center in Albany, N.Y., Williams and Wilson began developing a simple, elegant communication interface based on brain activity related to changes in an object on screen.

The interface consists, essentially, 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," says Williams. "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 w
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