It’s been a while since we covered news about the tongue controller which enables quadriplegics the ability to operate wheelchairs and other devices by moving their tongues. The newest prototype of the Tongue Drive System makes use of a dental retainer with sensors to help control the system. 
The embedded sensors within the retainer track the movements of a small magnet attached to the tongue.
Problems related to using a headset as the magnet sensor in the earlier version of the system required the team to try a wireless dental retainer. The retainer is powered by a rechargeable lithium-ion battery and makes use of magnetic field sensors on the four corners of the device to track the magnet’s movements. The sensors transmit their information to an iPod or iPhone and special software enables the mobile device to control the movements of a cursor on a computer screen or to work as a substitute for a joystick in a powered wheelchair.
The Tongue Drive System can be made to interface with any standard electric wheelchair. Since the new version has an improved sensitivity, additional tongue movement commands can be programmed into the system. Earlier tests using the older version of the system have been done with 11 patients with high-level spinal cord injuries. These tests showed that after getting used to the device, the people in the study group were able to operate their wheelchairs and computer cursors faster and with more accuracy. The researchers expect even better results from the intraoral Tongue Drive System.
Press release: Mouth Gear: Tongue Drive System Goes Inside the Mouth to Improve Performance and User Comfort
Flashbacks: Tongue Controller Looks Promising For Paralyzed; Tongue Controller Promises Better Device Interaction for Severely Disabled