Aiding the blind with sonar vision

PARIS – Researchers said they are developing a sonar vision system that enables the congenitally blind to perceive the shape of a face, a house, even words and letters.

A team of researchers at the Hebrew University of Jerusalem, in collaboration with French cognitive neuroimaging specialists at the ICM Brain and Bone Marrow Institute Research Center (Inserm/UPMC/AP-HP) and NeuroSpin (CEA-Inserm), said they observed that, in people who are blind from birth, the areas of the cerebral cortex normally devoted to reading responds to stimulation.

Researchers said their device consists of a small video camera embedded in a pair of eyeglasses, a laptop or a smartphone which transforms images into sounds, and stereo headphones to hear the sounds produced. For instance, an oblique line is transformed into an increasingly high-pitched sound or an increasingly lower-pitched sound, researchers said.


After 70 hours of training, researchers claimed that the blind can correctly classify images into specific categories such as faces, houses. They are also able to perceive where people are located in a room or some facial expressions. They can even read words and letters.

Seeking to better understand what happens in the brain when a blind person learns to “see” through sounds, researchers developed a functional MRI study. They observed that the regions of the cortex normally devoted to visual perception become highly activated in response to the “sonar vision” of letters, faces or houses.

“These results suggest that it may be possible, with the right technology and rehabilitation, to ‘wake up’ certain areas of the brain and access certain aspects of the visual world, even after years, or even a lifetime of blindness,” commented Laurent Cohen at ICM Research Center.

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