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", stated Justin Williams, a UW-Madison assistant professor of biomedical engineering and Adam 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, New York, Justin Williams and Adam 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", stated Justin 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 what I was just paying attention to'. And you see a momentary change in brain activity."
Adam Wilson, who used the interface to post the Twitter update, likens it to texting on a cell phone. "You have to press a button four times to get the character you want", he said of texting. "So this is kind of a slow process at first." However, as with texting, users improve as they practise using the interface. "I've seen people do up to eight characters per minute", stated Adam Wilson.
A free service, Twitter has been called a "micro-blogging" tool. User updates, called tweets, have a 140-character limit - a manageable message length that fits locked-in users' capabilities, according to Justin Williams.
Tweets are displayed on the user's profile page and delivered to other Twitter users who have signed up to receive them. "So someone could simply tell family and friends how they're feeling today", stated Justin Williams. "People at the other end can be following their thread and never know that the person is disabled. That would really be an enabling type of communication means for those people, and I think it would make them feel, in the on-line world, that they're not that much different from everybody else. That's why we did these things."
Gerwin Schalk agreed. "This is one of the first - and perhaps most useful - integrations of brain-computer interface techniques with Internet technologies to date", he stated.
While widespread implementation of brain-computer interface technologies is still years down the road, Wadsworth Center researchers, as well as those at the University of Tübingen in Germany, are starting in-home trials of the equipment. Adam Wilson, who will finish his Ph.D. soon and begin postdoctoral research at Wadsworth, plans to include Twitter in the trials.
Justin Williams hopes the Twitter application is the nudge researchers need to refine development of the in-home technology. "A lot of the things that we've been doing are more scientific exercises", he stated. "This is one of the first examples where we've found something that would be immediately useful to a much larger community of people with neurological deficits."
Funding for the research comes from the National Institutes of Health, the UW-Madison Institute for Clinical and Translational Research, the UW-Madison W.H. Coulter Translational Research Partnership in Biomedical Engineering and the Wisconsin Alumni Research Foundation.