People who have lived in the dark from birth have now found they don’t need their eyes to see. A new device developed by Amir Amedi from the Hebrew University of Jerusalem in Israel and colleagues is giving congenitally blind adults the ability to interpret visual information from sound.
People listen to sounds that illustrate an object or a facial expression, then describe what they are “seeing”. The system can also be used to read by assigning sounds to letters.
A tiny camera is strapped to the user’s head and connected to a computer or smartphone. An algorithm converts images to sound, providing a depiction of an object via headphones. Sound dips higher or lower to represent the surface of a shape, allowing the person to form a representation in their mind. It took about 70 hours of training for a blind person to learn to describe a range of images.
By monitoring the neural activity of blind people using the device, Amedi and his team found that even though the users weren’t using their eyes, their visual cortex was activated by the soundscapes. This shows, for the first time, that specialised areas responsible for object recognition or reading can still be triggered later in life even if they have never been exposed to normal visual information.
The team now plans to enhance the experience by using music to represent colours, shapes and locations. Using the system is mentally demanding so more pleasant audio should help make it more relaxing.