A magnetic stud lets Jason DiSanto, who is paralyzed from the neck down, use his tongue like a joystick to drive a wheelchair.
DiSanto took part in a recent study to test the effectiveness of the Tongue Drive System. Since a diving accident in 2009 he’s been using a sip-and-puff system—the most popular assistive technology for controlling a wheelchair.
“With the sip-and-puff system, there is always a straw in front of my face. With the Tongue Drive, people can see you, not just your adaptive equipment,” says DiSanto.
Results from the study, published in the journal Science Translational Medicine, show that wheelchair users were able to access computers and execute commands for their wheelchairs at speeds that were significantly faster than those recorded in sip-and-puff wheelchairs, but with equal accuracy.
With the Tongue Drive System, sensors in the tongue stud relay the tongue’s position to a headset, which then executes up to six commands based on the tongue position.
“It’s really easy to understand what the Tongue Drive System can do and what it is good for,” says study co-author Maysam Ghovanloo, an associate professor in the School of Electrical and Computer Engineering at the Georgia Institute of Technology. “Now, we have solid proof that people with disabilities can potentially benefit from it.”
The research team had subjects complete a set of tasks commonly used in similar clinical trials. Subjects in the trials were either able-bodied or people with tetraplegia.
“By the end of the trials, everybody preferred the Tongue Drive System over their current assistive technology,” says Joy Bruce, manager of Shepherd Center’s Spinal Cord Injury Lab and co-author of the study. “It allows them to engage their environment in a way that is otherwise not possible for them.”
Researchers compared how able-bodied subjects were able to execute commands either with the Tongue Drive System or with a keypad and mouse.
For example, targets randomly appeared on a computer screen and the subjects had to move the cursor to click on the target. Scientists are able to calculate how much information is transferred from a person’s brain to the computer as they perform a point-and-click task. The performance gap narrowed throughout the trial between the keypad and mouse and the Tongue Drive System.
For the first time, the research team showed that people with tetraplegia can maneuver a wheelchair better with the Tongue Drive System than with the sip-and-puff system.
On average, the performance of 11 subjects with tetraplegia using the Tongue Drive System was three times faster than their performance with the sip-and-puff system, but with the same level of accuracy, even though more than half of the patients had years of daily experience with sip-and-puff technology.
Why tongue piercing?
The idea for piercing the tongue with the magnet was the inspiration of Anne Laumann, professor of dermatology at Northwestern University Feinberg School of Medicine and a lead investigator of the trial there. She had read about an early stage of Tongue Drive System using a glued-on tongue magnet. The problem was the magnet fell off after a few hours and aspiration of the loose magnet was a real danger to these users.
“Tongue piercing put to medical use—who would have thought it? It is needed and it works!” Laumann says.
The experiments were repeated over five weeks for the able-bodied test group, and over six weeks for the tetraplegic group. All of the subjects with tetraplegia were able to complete the trial.
The tetraplegic group was using the Tongue Drive System just one day each week, but their improvement in performance was dramatic.
“We saw a huge, very significant improvement in their performance from session one to session two,” Ghovanloo says. “That’s an indicator of how quickly people learn this.”
The Tongue Drive System isn’t quite ready for commercialization, but Ghovanloo’s startup company, Bionic Sciences, is working with Georgia Tech to move the technology forward.
The National Institute of Biomedical Imaging and Bioengineering and the National Science Foundation funded the research. Additional scientists from Shepherd Center in Atlanta, the Rehabilitation Institute of Chicago, and Northwestern were involved in the study.
Source: Georgia Tech