Activating the ‘mind’s eye’ — sounds, instead of eyesight, can be alternative vision

Common wisdom has it that if the visual cortex in the brain is deprived of visual information in early infanthood, it may never develop properly its functional specialization, making sight restoration later in life almost impossible.

Scientists at the Hebrew University of Jerusalem and in France have now shown that blind people – using specialized photographic and sound equipment – can actually “see” and describe objects and even identify letters and words.

The new study by a team of researchers, led by Prof. Amir Amedi of the Edmond and Lily Safra Center for Brain Sciences and the Institute for Medical Research Israel-Canada at the Hebrew University and Ph.D. candidate Ella Striem-Amit, has demonstrated how this achievement is possible through the use of a unique training paradigm, using sensory substitution devices (SSDs).

SSDs are non-invasive sensory aids that provide visual information to the blind via their existing senses. For example, using a visual-to-auditory SSD in a clinical or everyday setting, users wear a miniature camera connected to a small computer (or smart phone) and stereo headphones.

The images are converted into “soundscapes,” using a predictable algorithm, allowing the user to listen to and then interpret the visual information coming from the camera. The blind participants using this device reach a level of visual acuity technically surpassing the world-agreed criterion of the World Health Organization (WHO) for blindness, as published in a previous study by the same group.