An early project by the two students involved creating a computer mouse that could be controlled remotely by "brain waves," a hot issue in many labs at the time. Neither student was a computer guru, so each relied on an innovative bit of software from National Instruments in Austin, Texas. The software, called LabVIEW, was a nice fit with their training at the university in that it encourages personal initiative in computer programming.
"It's extremely empowering," Callahan said.
The importance of that early research is that it launched the two on a determined course to help the human brain carry out its commands in patients who can no longer do it themselves.
The wheelchair, created partly as a public relations tool so people could better understand the technology, is surprisingly simple in its operation. A tiny sensor, mounted in a collar, is positioned directly over the vocal chords, where it can "read" the electronic signals sent by the brain.
"We pick up a very small instruction signal on the surface of the skin because the material underneath the skin, the blood and the tissues, are moderately conductive," Callahan said. "We can pick up the signal and turn it into useful things," in this case, speech.
In order to work, the user has to do more than just think about what the patient wants to say, or what the wheelchair is supposed to do. The patient must think about saying what he or she wants to do, thus sending the signal to the vocal chords.
"If you are just thinking something, like turning the wheelchair to the right, our stuff will do absolutely nothing," he said. "There's no signal there. However, if you want to say turn right, then your brain will send the signal to your vocal chords, which we pick up."
So it takes a little practice learning how to get the job done, but Coleman has learned how to control the wheelchair without moving his hands by simply thinking about saying the words that the sensor can detect and send to the computer, where they are translated into commands.
But that's not the immediate goal of the pair.
"The goal of our technology is not to move a wheelchair," Callahan said. "The goal of our technology is to allow people to speak."
According to the U.S. Census Bureau, there are about 2.5 million people in the United States who have limited speech, and about 500,000 who cannot speak at all. Globally, Callahan said, "about 60 million people worldwide have either limited or no form of speech."
So there are a lot of folks out there who could benefit from this technology. Let's hope it works as well in the real world as it does in the lab.
Lee Dye is a former science writer for the Los Angeles Times. He now lives in Juneau, Alaska.