Simple Innovation to Electrodes Makes a Big Difference
The electroencephalogram (EEG) for human uses has been around since 1924. Small metal discs placed along the scalp measure electrical activity in the human brain, important in diagnosing or evaluating epilepsy, sleep disorders and other conditions.
But these electrodes have changed little since their introduction, and are far from perfect. Among other things, they pick up extraneous noise and movement in addition to brain wave activity, often making the readings difficult to interpret.
Walt Besio thinks he has a better way.
The National Science Foundation-funded scientist, who is associate professor of biomedical engineering at the University of Rhode Island, has invented a new and improved electrode, one that produces a performance difference that he says is akin to “taking the rabbit ears you used to have for your television set, and converting to high definition.”
His innovation is relatively simple, but apparently makes a big difference. Besio added two new metal rings around the basic disc, a change that eliminates outside noises and improves spatial resolution.
"EEG has two main problems: It’s very noisy and contaminated with artifacts, and it’s spatial resolution is bad," he explains. "We have improved the signal-to-noise ratio. It’s four times better than it was before. Because it is now a very local signal, it means we can put electrodes closer together, which improves spatial resolution, meaning you can better determine where the signal is coming from."
The additional rings work almost like an inner tube tossed on top of a rippling body of water. “The water is flat in the center of the inner tube and choppy on the outside,” he says. “The outer rings on the electrodes behave like that inner tube.”
For researchers and clinicians, having improved electrodes could open up potential new uses, as well as improve current ones-more accurate epilepsy diagnosis, for example, as well as the promise of “reading” someone’s thoughts in the future, with the goal, for example, of activating an otherwise inert body part, such as an arm or leg, and ultimately helping people with spinal cord injuries.
The aim is to have the highly sensitive electrodes first translate a person’s thoughts into electrical impulses that can be read by a computer, then, eventually move to robots, and later, limbs. Other scientists are conducting similar research, but Besio wants to show “that it works better with these types of electrodes.”
