A device that sits in a blind person's mouth and allows them to see with their tongue has been developed by neuropsychologist Maurice Ptito of Université de Montréal. In just the first few minutes of use, a subject is able to build up a fairly clear picture of alphabetic characters placed in various positions and transmitted by electrical impulses to the device on his tongue.
The Tongue Display Unit (TDU) can activate areas that are normally reserved for visual information and are unused when someone suffers from congenital blindness. "The tongue will never replace the eye, of course," says Prof. Ptito. "But for people born blind, the cerebral cortex, which is normally used for vision, is reactivated by this device. The electrical activity, recorded by a scan, is very clear about this."
Prof. Ptito. is already considering future applications. "We can imagine a camera installed in the eye, which transmits an image from a device worn on the belt. This would send an electrical stimulus to the lingual stimulator mounted on a trip indicator the user wears under the palate. To have access to the camera's images, all he would have to do is press his tongue against it."
In the shorter term, he suggests a system that would replace the Braille alphabet. In fact, if the tongue were capable of "reading" the letters of the alphabet, it would be able to read texts broadcast via electrical signals.
It's not surprising that the tongue is the focus of Ptito's work. The processing of information from the tongue occupies a large part of the brain, and the presence of saliva creates excellent conditions for the transmission of electrical stimuli. "Our research shows that our senses are recyclable, in a way," explains Ptito.
