Tongue control

A new technology developed by engineers at the Georgia Institute of Technology could help individuals with severe disabilities lead more independent lives.

The so-called 'Tongue Drive' system, developed by Maysam Ghovanloo, an assistant professor in the Georgia Tech School of Electrical and Computer Engineering, allows individuals with disabilities to direct the movement of a cursor across a computer screen, or a powered wheelchair around a room, simply by moving their tongue.

'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,' said Ghovanloo, who started working on this project about three years ago at North Carolina State University.

Here's how the system works. First, a small magnet the size of a grain of rice is attached to an individual's tongue by implantation, piercing or adhesive. Movement of the magnet is detected by an array of magnetic field sensors mounted on a headset outside the mouth or on an orthodontic brace inside the mouth. The output from these sensors is then wirelessly transmitted to a portable computer, which can be carried on the user's clothing or wheelchair.

Next, the signals from the sensor are processed to determine the relative motion of the magnet with respect to the array of sensors in real-time. This 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.

The system can potentially capture a large number of tongue movements, each of which can represent a different user command. A unique set of specific tongue movements can be tailored for each individual based on the user's abilities, oral anatomy, personal preferences and lifestyle.

'An individual could potentially train our system to recognise touching each tooth as a different command,' explained Ghovanloo. '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.'

Ghovanloo is now teaming up with the Shepherd Center, an Atlanta-based catastrophic care hospital, and the Georgia Tech Center for Assistive Technology and Environmental Access, to conduct trials of the system by people with severe disabilities.

His research team has also begun to develop software to connect the Tongue Drive system to communication tools such as text generators, speech synthesisers and readers. In addition, they plan to add control commands, such as switching the system into standby mode to permit the user to eat, sleep or engage in a conversation.