Tongue Power

In a vital breakthrough, scientists at the Georgia Institute of Technology have developed a new revolutionary technology to help individuals with disabilities to control wheelchairs, computers and other devices simply by using their tongue. Scientists at the Georgia Institute of Technology say that the new technology called Tongue Drive System will be helpful to individuals with serious disabilities, such as those with severe spinal cord injuries and will allow them to lead more active and independent lives. This technology enables individuals to manoeuver a powered wheelchair or control a mouse cursor using simple tongue movements. The scientist community has described this technology as avant-garde, as similar things have been around for some time but not of this complexity or versatility.

            According to Georgia Institute of Technology Research News, “The clinical trial has validated that the Tongue Drive System is intuitive and quite simple for individuals with high-level spinal cord injuries to use.” Maysam Ghovanloo, an Assistant Professor at the School of Electrical and Computer Engineering in the Georgia Institute of Technology, pointed out: “Trial participants were able to easily remember and correctly issue tongue commands to play computer games and drive a powered wheelchair around an obstacle course with very little prior training.”

            At the beginning of each trial, Ghovanloo and graduate students Xueliang Huo and Chih-wen Cheng attached a small magnet only a size of a grain of rice — to the participant’s tongue using implantation, piercing, or tissue adhesive. Movement of this magnetic tracer was detected by an array of magnetic field sensors mounted on wireless headphones worn by the subject. The sensor output signals were wirelessly transmitted to a portable computer, which was carried on the wheelchair. The signals were processed to determine the relative motion of the magnet with respect to the array of sensors in real-time. This information was then used to control the movements of the cursor on a computer screen or to substitute for the joystick function in a powered wheelchair.

            Ghovanloo 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. Before using the Tongue Drive System, the subjects trained the computer to understand how they would like to move their tongues to indicate different commands. A unique set of specific tongue movements was tailored for each individual based on the user’s abilities, oral anatomy and personal preferences. Each subject operated the powered wheelchair using two different control strategies: discrete mode, which was designed for novice users, and continuous mode for more experienced users. The results of the trials showed 100 per cent of commands were accurate with the response time less than one second, which equals to an information transfer rate of approximately 150 bits per minute.

Elaborating on its distinct charateristic, Ghovanloo said: “The Tongue Drive System seems to be much more supportable, if there were a failure of some component within the system. With the old tongue-touch keypad, if the system went down, then the user lost all of the functions of the wheelchair, phone, computer and environmental control. But this system’s approach is much more repairable, should a fault arise, which is critical for systems for which so much function is depended upon.”

            A future system upgrade will be to move the sensors inside the user’s mouth, according to Ghovanloo. This will be an important step for users who are very impaired and cannot reposition the system for best results, said Ghovanloo. He his team also plan to test the ability of the system to operate by people with severe disabilities. The next step of the research is to develop software to connect the Tongue Drive System to great number of devices such as text generators, speech synthesizers and readers.

By Niharika