Washington, June 30 : Engineers at the Georgia Institute of Technology have developed a novel system that can enable individuals with disabilities to operate a computer, control a powered wheelchair, and interact with their environments simply by moving their tongues.
"This device could revolutionize the field of assistive technologies by helping individuals with severe disabilities, such as those with high-level spinal cord injuries, return to rich, active, independent and productive lives," said Maysam Ghovanloo, an assistant professor in the Georgia Tech School of Electrical and Computer Engineering.
Ghovanloo worked with graduate student Xueliang Huo to develop the Tongue Drive system, on which they gave a presentation at the 2008 Rehabilitation Engineering and Assistive Technology Society of North America (RESNA) Annual Conference in Washington, D.C.
The system involved a small magnet, the size of a grain of rice, which can be attached to an individual's tongue by implantation, piercing or tissue adhesive.
Once attached, the magnet can allow tongue motion to direct the movement of a cursor across a computer screen, or a powered wheelchair around a room.
"We chose the tongue to operate the system because unlike hands and feet, which are controlled by the brain through the spinal cord, the tongue is directly connected to the brain by a cranial nerve that generally escapes damage in severe spinal cord injuries or neuromuscular diseases. Tongue movements are also fast, accurate and do not require much thinking, concentration or effort," said Ghovanloo, who started working on the project about three years ago at North Carolina State University.
The system also uses an array of magnetic field sensors that detect the movement of the magnetic tracer, and wirelessly transmit signals to a portable computer that can be carried on the user's clothing or wheelchair.
The sensor output signals are processed to determine the relative motion of the magnet with respect to the array of sensors in real-time, and the information is then used to control the movements of a cursor on the computer screen, or to substitute for the joystick function in a powered wheelchair.
"An individual could potentially train our system to recognize touching each tooth as a different command. The ability to train our system with as many commands as an individual can comfortably remember is a significant advantage over the common sip-n-puff device that acts as a simple switch controlled by sucking or blowing through a straw," said Ghovanloo.
What makes the Tongue Drive system quite attractive is the fact that it is non-invasive, and does not require brain surgery like some of the brain-computer interface technologies.
The researchers used their system on six able-bodied individuals during a trial, wherein each participant defined six tongue commands that would substitute for computer mouse tasks - left, right, up and down pointer movements, and single- and double-click.
Ghovanloo said that the results of the computer access test by novice users with the current Tongue Drive prototype showed a response time of less than one second with almost 100 per cent accuracy for the six individual commands, which is equivalent to an information transfer rate of approximately 150 bits per minute and much faster than the bandwidth of most brain-computer interfaces.
The researchers have also tested the ability of twelve able-bodied individuals to operate an electric-powered wheelchair with the Tongue Drive system.
Ghovanloo revealed that the next step will be to test and assess the usability and aceeptablitiy of their system by people with severe disabilities.
The researchers have also begun to develop software to connect the Tongue Drive system to a wide variety of readily available communication tools such as text generators, speech synthesizers and readers.
They also have plans to add control commands that will switch the system into standby mode to permit the user to eat, sleep or engage in a conversation while extending battery life.
"We hope this technology will reduce the need of individuals with severe disabilities to receive continuous assistance from family members or caregivers, thus significantly reducing healthcare and assistance costs. This system may also make it easier for them to work and communicate with others, such as friends and family," Ghovanloo said.
An article about this system is also scheduled to appear in an upcoming issue of the Journal of Rehabilitation Research and Development.