Tongue Display Unit allows blind people to see with their tongue

Jun 2 2004

Sitting blindfolded with a device equipped with 144 pixels in his mouth, any journalist would wonder about his career choice. But after a few minutes of experimentation, you have to recognize that the system developed by neuropsychologist Maurice Ptito of Université de Montréal, together with colleagues in Denmark and the United States , to allow blind people to “see with their tongue” appears strangely effective. In just the first few minutes, the subject is able to build up a fairly clear picture of the letter “T” 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.” When we press the researcher to find out more about possible applications of this system, he delights in describing a miniaturized system worthy of the Bionic Man. “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, we can imagine 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. When it has been perfected, this system could considerably improve the quality of life of blind persons. It would be a “hands-off” non-invasive system.

It is no surprise that the tongue is the focus of Maurice Ptito’s work. Processing of information from this organ 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 neuropsychologist Maurice Ptito of the School of Optometry , who collaborated with a researcher from the University of Aarhus, Denmark, Ron Kupers.

Started in Scandinavia , this research is now being pursued in Canada by a Master’s student, Solvej Moesgaard. Professor Ptito was able to obtain the equipment he needed to advance the project thanks to various sources of funding. Research on the congenitally blind has already begun, and the School of Optometry is taking advantage of the proximity of the Nazareth and Louis Braille Institute in the same building to recruit research subjects.