An experimental new one, however, could allow people who lack the use of their hands to control electronic devices – and it would do so by tracking their bite patterns.

Currently in functional prototype form, the assistive device is being developed by scientists from the National University of Singapore and China's Tsinghua University. The research is being led by NU Singapore's Prof. Liu Xiaogang.

Unlike existing alternatives such as voice recognition systems, the mouthguard isn't stymied by loud background noises, nor does it need a large operating memory. And unlike eye-tracking systems, it doesn't require a camera to be situated in front of the user's face. It also isn't as invasive or awkward as setups that monitor the user's brainwaves.

Instead, the flexible device incorporates a series of pressure-sensitive contact pads, each one containing differently colored phosphors. As the user bites down on the mouthguard and places pressure on those pads, they emit light in their respective colors, at varying intensities depending on the amount of pressure applied.

Biting the mouthguard in different fashions produces different light patterns. An optoelectronic sensor detects those patterns, and relays the data to a computer. Utilizing machine-learning-based algorithms, that computer matches each pattern up to a predetermined corresponding command.

"The user can bite left, right, front, or slightly left or right. The user can also bite at the same position repeatedly to relay different data," Xiaogang told us. "Besides text messages and commands to control wheelchairs, users can also make phone calls and play a virtual piano keyboard. It is also possible to control electronic home appliances."