We’ve known for a long time that brain function involves sending electrical impulses, but it is only in recent years that researchers are finding effective ways to harness that energy without having to implant electrodes into the brain. One of the most exciting developments is a wired cap that lets people who cannot control any physical movements do things like use email, and turn a light switch or television set on and off using only their thoughts to control a computer.
Technology developed at the Wadsworth Center, a laboratory that is part of the New York State Department of Health, is now robust enough to be moved out of the lab and into the homes of several severely disabled people.
Users wear a cap fitted with eight electrodes that pick up and amplify brain signals from the surface of the scalp. The software developed by the lab uses a flashing matrix system for choosing letters, so that experienced users can type as fast as four to six words a minute.
Moving from the lab to a real-world environment did pose some usability challenges. The system had to be simplified to make it easy for operators to get the cap onto the wearer correctly. It had to be designed so that people with poor vision could see the monitor and so that the prompts were very clear. The system has now been refined so that the operator only has to push one switch to get it started, and the system can diagnose many problems itself and report them to the operator, who can make the needed adjustments.
The real-world environment sometimes means intensive detective work to figure out why the system isn’t working as expected. “In one house we had repeated crashes,” reported Dr. Jonathan Wolpaw, chief, Laboratory of Nervous System Disorders. “It took us a long time to figure out that the plug into the wall was unstable. These things seem trivial once you find them, but if you aren’t there, they can be hard to find.”
Other challenges not experienced in the lab include people in the home who might wander into the user’s room and play with the computer, disturbing the settings.
Next steps include a usability focus: making the cap more comfortable to wear for six to eight hours a day and making it look better. Most users are grateful to have the new-found communication ability, but they want to look good too!
You can see a video of the cap.
