New technology allows quadriplegics to control their wheelchair with a tongue stud.
After a diving accident left Jason DiSanto paralyzed from the neck down in 2009, he had to learn how to navigate life from a powered wheelchair, which he controls with a sip-and-puff system.
Users sip or puff air into a straw mounted on their wheelchair to execute four basic commands that drive the chair.
But results from a recent clinical study offer hope that sip-and-puff users like DiSanto could gain a higher level of independence than offered by this common assistive technology.
Better Than Sip-and-Puff
In the study, individuals with paralysis used a tongue-controlled technology 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.
This study is the first to show that the wireless and wearable Tongue Drive System outperforms sip-and-puff in controlling wheelchairs.
Shepherd Center clinicians insert a device used to control the Tongue Drive System by piercing Jason DiSanto's tongue with a magnetic stud.
The Tongue Drive System is controlled by the position of the user’s tongue. A magnetic tongue stud lets a person use his or her tongue as a joystick to drive the wheelchair. 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.
The Tongue Drive System holds promise for patients who have lost the use of their arms and legs, a condition known as tetraplegia or quadriplegia.
“It’s really easy to understand what the Tongue Drive System can do and what it is good for,” says Maysam Ghovanloo, an associate professor in the School of Electrical and Computer Engineering at the Georgia Institute of Technology, and a study co-author and principal investigator. “Now, we have solid proof that people with disabilities can potentially benefit from it.”
“Very Exciting Finding”
Published in the Nov. 27 issue of Science Translational Medicine, the study was funded by The National Institute of Biomedical Imaging and Bioengineering and the National Science Foundation.
Scientists from the Shepherd Center in Atlanta, the Rehabilitation Institute of Chicago and the Northwestern University Feinberg School of Medicine were also involved in the study.
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 the 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.”
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.
“That was a very exciting finding,” Ghovanloo says. “It attests to how quickly and accurately you can move your tongue.”
The idea for piercing the tongue with the magnet was the inspiration of Anne Laumann, MD, professor of dermatology at Feinberg and a lead investigator of the Northwestern trial.
She had read about an early stage of the 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 completed the trial, which Ghovanloo called an “exciting” and “major finding.”
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.”
Experiments on the Tongue Drive System to date have been done in the lab or hospital. In future studies, scientists will test how the Tongue Drive System performs outside of the controlled clinical environment.
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.
DiSanto hopes he’ll soon be able to use a tongue-powered wheelchair outside of the hospital, which would help him gain some independence he lost after his diving accident.
“The Tongue Drive System will greatly increase my quality of life when I can start using it everywhere I go,” DiSanto says. “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.”
To see a video of the Tongue Drive in action or for more information, visit shepherd.org.
Article and photos courtesy of the Shepherd Center and the Georgia Institute of Technology.
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