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Interviewee: Maysam Ghovanloo, Georgia
A Magnetic Solution
Researchers have come up with a way someone can use their tongue much like a joystick letting the user control everything from motorized wheelchairs to computers.
The secret is a magnet placed on the user’s tongue and sensors outside the mouth that work with a computer to do the rest. Maysam Ghovanloo , Assistant Professor at the School of Computer and Electrical Engineering at Georgia Institute of Technology says when the magnet moves, its magnetic field changes and that, “By measuring the changes in the magnetic field these sensors basically send that information to a computer.”
The system is primarily intended to help people who are paralyzed by a spinal injury operate a powered wheelchair. Ghovanloo says the reason the researchers are focusing on the tongue is that, “No matter the spine injury they don’t lose the tongue because it’s directly connected to the brain.”
Sip And Puff
This system is being developed as an alternative to those already available . With the most common device, the operator of the wheelchair either sips or puffs on a straw like device to direct a wheelchair. Ghovanloo says such a system is slow to use because menus must be memorized and drilling down through the menu choices can be cumbersome.
A second system is an eye tracker where the user wears a camera that points back to their eyes. While the eyes are quick and agile, Ghovanloo notes people still need to use them to see where they’re going, meaning a momentary glance might send the wrong signal to the wheelchair.
Since the tongue is also needed for speech and eating, Ghovanloo says, “We have added a certain command that would basically put the system into a standby mode.”
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His is not the only system concentrating on finding new ways to use the mouth to control devices. The University of Washington’s Jeff Bilmes is developing what he calls a, “vocal joystick” where sounds are used to control a device.
Since the magnetic field from the magnet on the tongue is very weak, the sensors outside the mouth are very sensitive. Ghovanloo says they were originally used for GPS devices and are so sensitive that the Earth’s own magnetic field was creating interference. He says, “We had to develop special signal processing … algorithms that would reject the external magnetic fields.” He added that, “The most important one would be the Earth’s magnetic field.”
He says so far they have gone through two series of human trials. One involved a wheelchair interface that they’ve tested using 12 able-bodied volunteers. Xueliang Huo is a graduate student at the School of Computer and Electrical Engineering who has both tested the wheelchair and trained others. He says the set up time is quite short, explaining that someone “Is required to repeatedly move his tongue to six different positions to define six different commands.” He adds it’s quite easy and that, “It takes about five minutes to do the whole training session.”
They presented their system at an annual conference on assistive technology in Washington, D.C.
Another version of the system works much like a computer mouse. Six volunteers have tested this system and it will be presented at a future conference.
Ghovanloo is hoping to expand this concept by assigning a person’s teeth to specific commands or letters, allowing people to type with their tongue by touching their tongue to various teeth, turning someone’s mouth into a “virtual keyboard.” He says since the tongue has almost as much capability and agility as our fingers, the biggest challenge will just be remembering what various tongue movements and positions mean.
Another goal is to shrink the sensing unit that the operator now must wear on their face.
This research was described at the 2008 Rehabilitation Engineering and Assistive Technology Society of North America Annual Conference in Washington, D.C. and was funded by the National Science Foundation and the Christopher and Dana Reeve Foundation .
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