People who are blind can learn to process visual input through sound—even after a lifetime of blindness, a new study published this month in the journal Neuron finds.
In their studies, researchers at the Hebrew University Medical School in Israel taught congenitally blind adults to use sensory substitution devices—non-invasive sensory aids that provide visual information—through the senses they do have. For example, using a visual-to-auditory sensory aid, images from a video camera are converted into "soundscapes" representing the images. These allowed users to listen to and then interpret the visual information coming from the camera or see the sounds.
"The adult brain is more flexible that we thought," said senior author of the study Amir Amedi of the Edmond and Lily Safra Center for Brain Sciences and the Institute for Medical Research Israel-Canada at the Hebrew University.
After being taught how to use the devices, blind people could use them to learn to read, with sounds representing visual images of letters, the researchers found, using a region of the brain called the visual word form area. In those who are sighted, this region is activated by seeing and reading letters.
After only tens of hours of training, this region of the brain in people who are blind also showed more activation for letters than for any of the other visual categories tested. The findings suggest that, at least in the blind, the tuning of the visual word form area to reading does not depend on vision, the study says.
The blind could also use the devices to recognize soundscapes of visually complex categories such as faces, houses, and body parts. The results suggest that distinguishing meaningful shapes does not require vision—even though brain activity needed to do so occurs in the part of the brain typically associated with vision in sighted individuals.
I wonder what kinds of applications these sensory substitution devices could have in schools. To get a better idea of how the sensory substitution devices work, check out this video.