Page 18 - Mobility Management, September 2018

CRT trends By Leila A. McNeill, Associate Editor
The Tongue Drive System A New Frontier in Assistive Technology & Power Wheelchairs
What if a person with tetra- plegia could control his or her environment with only a flick of the tongue? For more than a decade, Maysam Ghovanloo, Ph.D., director of the Bionics lab at The Georgia Institute of Technology, and his team, including doctoral student Nazmus Sahadat and a few others before him, have been working to make this a reality with the Tongue Drive System (TDS).
Though the tongue may
be an unlikely appendage to lead the way for the future of power wheelchairs, it is what makes the TDS
a uniquely effective assistive technology. Nearly all people with tetraplegia and other spinal cord-related injuries maintain control of their tongue, a highly deft and surprisingly strong muscle that becomes an ideal “joystick” for people who have lost control and dexterity in their hands and fingers.
How Does TDS work?
The TDS device is made up of two principle parts: a tongue magnet and a headset. The magnet, affixed
to the tongue with adhesive for short-term use or implanted in the tongue inside a barbell for long-
term use, communicates with the headset, which
has magnetic sensors along both sides of the face.
If a user intends to turn left in the wheelchair, he/she touches the tongue to the inside of the left cheek to communicate the command to the headset. A simple tongue piercing could not achieve this desired result. The magnet creates an invisible magnetic field that the headset is able to detect, process and convert into directional commands.
Ghovanloo began developing TDS in 2005, when
he was an assistant professor at North Carolina State University. It was here that he and his team created a prototype of the system with a grant from the Christopher & Dana Reeve Foundation. When he later moved to Georgia Tech, Ghovanloo and his team partnered with Shepherd Center in Atlanta and later, with another larger grant from the NIH, the Rehabilitation Institute of Chicago at the Shirley Ryan AbilityLab to start clinic trials with TDS.
Clinical trials, spanning 2012-2013, returned promising results, which were published in Science Translational Medicine. “In [the Atlanta/Chicago] study, we were
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looking at performance using
the Tongue Drive System in comparison to some of the most popular devices, such as sip-and- puff or head array,” Ghovanloo explained. “The focus was to compare their performance for computer access and naviga- tional purposes.”
TDS outperformed sip-and-puff. According to the results, with TDS, people with tetraplegia carried out tasks three times faster — and
with an equal level of accuracy.
TDS Improved
Since the 2012-2013 clinical trials, Ghovanloo and his team have been working to bring the technology to market and to improve upon the original TDS technology. “What we have been working on has been two-fold,”
he explained. “We have been trying to ‘productize,’ to convert that proof-of-concept prototype to a version that can actually be deployed at home, in the office, in the hospital so that end users can actually use it.”
This process, of course, involves finding enough funding to bring the technology to market for wide- spread use. “The TDS is really a medical device, and to bring a medical device to market, we are talking about investments in the order of a few million to tens of millions of dollars,” added Ghovanloo. He and his team are being considered for a Phase II Small Business Innovation Research grant from the National Science Foundation, which will allow them to continue developing their tech- nology and make it market ready.
On the development and academic side, Ghovanloo said, “What we are working on is to add additional control modality so that the original Tongue Drive as the name suggests allows a person who is completely para- lyzed, a tetraplegic person, to use his or her voluntary tongue motion to access a computer, control a wheel- chair, or a smartphone.” This more robust system is called Multi-Modal Tongue Drive System (mTDS).
The first version of the TDS from the 2012-2013 studies only used the tongue to communicate switch-based commands, but mTDS responds also to head and voice commands. Working with other smart technologies, such as Bluetooth built into the headset, and voice recogni- tion software, mTDS has the potential to allow a user not
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PHOTOS COURTESY MAYSAM GHOVANLOO