Neuropsychology: The blind can walk thanks to an eye on the tongue

published in Forum Express

12 décembre 2007
'The only limits with this device are the ones set by the researcher': Daniel Chebat

“It’s the first time I make my way across a cluttered course of several meters without the help of my cane,” explains 35-year-old M.L. who has been blind since birth. He accomplished this thanks to a device mounted on his tongue, which creates a mental image of the space around him.

In a video recorded by Daniel Chebat, PhD student in experimental neuropsychology at the Université de Montréal School of Optometry, M.L. is seen making his way down a hallway while avoiding a block on his left, a pipe on his right and the low wall by his feet. This is possible thanks to a camera mounted on his glasses which transmits images to a 144-pixel unit on his tongue.

The Tongue Display Unit (TDU) was tested for the first time in the summer of 2006 on a 14-meter course in Montreal. It proved to be remarkably efficient. “The 15 blind people from birth we tested showed extraordinary ability after just a few hours of training,” explains the 28-year-old Chebat. M.L., an engineer himself, said he looked forward to having a similar device, while other test subjects added that such a device could eventually replace their white cane.

Chebat explains that this is not about making the blind see. The vision of the blind is not modified by the TDU and remains at approximately 1/90. But the TDU allows them to recognize simple shapes in their surrounding environment thanks to the electrical charges transmitted on their taste buds.

“We are doing basic research and our experiment confirms what we intended to demonstrate regarding the activation of the visual cortex. It’s fascinating: the brain of the blind processes the data coming from the TDU as if it were visual data,” explains Chebat who works under the supervision of Professor Maurice Ptito who is well known for his work on neuronal plasticity.

The device used for this experiment was developed by Professor Paul Bach-y Rita of the University of Wisconsin-Madison and it quickly interested Professor Ptito. The success Ptito obtained won him international acclaim as well as substantial funding.

Ptito is the recipient of the Colonel Harland Sanders Chair in Vision Sciences. The funding allowed him to set up research labs and to build testing courses at the School of Optometry in Montreal and at the Hvidovre University Hospital in Denmark where teams of four people work under his supervision.

Chebat is currently leading three research projects in Canada and Denmark, which will eventually be the focus of scientific articles. The project in which M.L. participated is about to be published while the two other projects are still at the experimental stage.

In the second project, he wants to explore the sensory acuity of the blind within the confines of a complex course made up of five corridors. The third project, intends to immerse users of the TDU in a video game. The test subject will be asked to maneuver inside a virtual environment transmitted onto his taste buds while a scanner observes his brain.

The observation of the brain during use of the TDU has yet to be done. “The only limits with this device are the ones set by the researcher,” says Chebat who is thrilled by the development of his research.

Researcher:
Daniel Chebat

E-mail:
dr.chebat@umontreal.ca

Telephone:
514 343-6111 , extension 4532

Funding:
Canadian Institutes of Health Research