Tongue Drive System Controls Wheelchairs, Computers
Author: Georgia Institute of Technology
Published: 2012/02/20 - Updated: 2025/11/11
Publication Details: Peer-Reviewed, Product Release, Update
Category Topic: Assistive Technology - Academic Publications
Page Content: Synopsis - Introduction - Main - Insights, Updates
Synopsis: This research, developed at Georgia Institute of Technology and presented at the IEEE International Solid-State Circuits Conference, describes a wireless assistive device that allows people with high-level spinal cord injuries to operate computers and control powered wheelchairs using tongue movements. The system works through magnetic field sensors embedded in a dental retainer that track a small magnet attached to the user's tongue, with signals wirelessly transmitted to an iPod or iPhone that interprets the commands in real-time.
The research represents a significant advancement from earlier headset-based prototypes because the intraoral design provides greater mechanical stability, eliminates calibration issues caused by headset shifting, and remains virtually invisible during use. Developed with support from the National Institutes of Health, National Science Foundation, and Christopher and Dana Reeve Foundation, the technology offers distinct advantages over traditional sip-and-puff devices by allowing users to program and access multiple commands simultaneously rather than being limited to simple switch-based controls.
Clinical trials at the Shepherd Center in Atlanta and the Rehabilitation Institute of Chicago demonstrated that users could learn the system quickly and showed progressive improvement in computer cursor control and wheelchair navigation through obstacle courses, with participants experiencing fewer collisions and faster completion times over the six-week testing period - Disabled World (DW).
Introduction
Tongue Drive is a wireless device that enables people with high-level spinal cord injuries to operate a computer and maneuver an electrically powered wheelchair simply by moving their tongues.
Main Content
Tongue Drive System
The Tongue Drive System is getting less conspicuous and more capable. The newest prototype of the system allows users to wear an inconspicuous dental retainer embedded with sensors to control the system.
The sensors track the location of a tiny magnet attached to users' tongues. In earlier versions of the Tongue Drive System, the sensors that track the movement of the magnet on the tongue were mounted on a headset worn by the user.
"By moving the sensors inside the mouth, we have created a Tongue Drive System with increased mechanical stability and comfort that is nearly unnoticeable," said Maysam Ghovanloo, an associate professor in the School of Electrical and Computer Engineering at the Georgia Institute of Technology.
The new intraoral Tongue Drive System was presented and demonstrated on Feb. 20, 2012, at the IEEE International Solid-State Circuits Conference in San Francisco. Development of the system is supported by the National Institutes of Health, National Science Foundation, and Christopher and Dana Reeve Foundation.
Magnetic Field Sensors
The new dental appliance contains magnetic field sensors on its four corners that detect the movement of a tiny magnet attached to the tongue. It also includes a rechargeable lithium-ion battery and an induction coil to charge the battery. The circuitry fits in the space available on the retainer, which sits against the roof of the mouth and is covered with an insulating, water-resistant material and vacuum-molded inside standard dental acrylic.
"One of the problems we encountered with the earlier headset was that it could shift on a user's head, and the system would need to be re-calibrated," explained Ghovanloo. "Because the dental appliance is worn inside the mouth and molded from dental impressions to fit tightly around an individual's teeth with clasps, it is protected from these disturbances."
When in use, the output signals from the sensors are wirelessly transmitted to an iPod or iPhone. Software installed on the iPod interprets the user's tongue commands by determining the relative position of the magnet concerning the array of sensors in real-time. This information is used to control the movements of a cursor on the computer screen or to substitute for the joystick function in a powered wheelchair.
Universal Interface
Ghovanloo and his team have also created a universal interface for the intraoral Tongue Drive System that attaches directly to a standard electric wheelchair. The interface boasts multiple functions: it not only holds the iPod but also wirelessly receives the sensor data and delivers it to the iPod, connects the iPod to the wheelchair, charges the iPod, and includes a container where the dental retainer can be placed at night for charging.
In preliminary tests, the intraoral device exhibited an increased signal-to-noise ratio, even when a smaller magnet was placed on the tongue. That improved sensitivity could allow additional commands to be programmed into the system. The existing Tongue Drive System that uses a headset interprets commands from seven different tongue movements.
The ability to train the system with additional commands - as many commands as an individual can comfortably remember - and having all of the commands available to the user at the same time are significant advantages over the common sip-n-puff device that acts as a simple switch controlled by sucking or blowing through a straw.
The researchers plan to begin testing the usability of the intraoral Tongue Drive System by non-disabled individuals soon and then move on to clinical trials to test its usability by people with high-level spinal cord injuries.
SCI
In recent months, Ghovanloo and his team have recruited 11 individuals with high-level spinal cord injuries to test the headset version of the system at the Atlanta-based Shepherd Center and the Rehabilitation Institute of Chicago.
Trial participants received a clinical tongue piercing and tongue stud that contained a tiny magnet embedded in the upper ball. They repeated two test sessions per week during a six-week period that assessed their ability to use the Tongue Drive System to operate a computer and navigate an electric wheelchair through an obstacle course.
"During the trials, users have been able to learn to use the system, move the computer cursor quicker and with more accuracy, and maneuver through the obstacle course faster and with fewer collisions," said Ghovanloo. "We expect even better results in the future when trial participants begin to use the intraoral Tongue Drive System daily."
Georgia Tech graduate students Abner Ayala-Acevedo, Xueliang Huo, Jeonghee Kim, Hague Park, and Xueli Xiao, and former postdoctoral fellow Benoit Gosselin also contributed to this work.
Insights, Analysis, and Developments
Editorial Note: The Tongue Drive System represents a meaningful shift in how assistive technology can restore independence and functionality for people with severe mobility limitations. What makes this development particularly noteworthy is not just the technical sophistication of the magnetic tracking system, but the practical design choices that prioritize user comfort and discretion - the move from external headset to dental retainer addresses real-world concerns about appearance and reliability that often determine whether assistive devices get used consistently. The system's ability to support multiple customizable commands gives users genuine control over their environment in ways that older switch-based technologies simply cannot match, potentially opening doors to employment, education, and social participation that might otherwise remain closed to individuals with high-level spinal cord injuries - Disabled World (DW).Attribution/Source(s): This peer reviewed publication was selected for publishing by the editors of Disabled World (DW) due to its relevance to the disability community. Originally authored by Georgia Institute of Technology and published on 2012/02/20, this content may have been edited for style, clarity, or brevity.