New Sound-Based Navigation Technology Allows the Blind More Freedom, and Could Help with Alzheimer's
Scans of the A6 area of the brain show that it's possible to substitute hearing for vision, regardless of age.
Researchers at Reichman University, Ariel University, and the Ben-Gurion University of the Negev have demonstrated that it's possible to activate visual navigation areas of the brain using sound — using sensory substitution devices (SSDs) as a tool for helping the blind to navigate unfamiliar areas.
"We explored the involvement of V6 [a visual stream area of the brain] in egocentric navigation in sighted and in congenitally blind (CB) participants navigating via an in-house distance-to-sound sensory substitution device (SSD), the EyeCane," the researchers explain of their work. "We performed two fMRI [Functional Magnetic Resonance Imaging] experiments on two independent datasets. In the first experiment, CB and sighted participants navigated the same mazes."
As was expected, when the sighted individuals navigated the maze using vision the targeted V6 area of the brain, which is responsible for integrating eye movements with retinal and visuo-motor signals, showed activity — which was entirely to be expected. The same area, however, showed activity when the CB participants navigated using a virtual version of the EyeCane device — relying not on vision at all but instead on the tool's ability to translate distance to objects and obstacles into sound.
The EyeCane, and other non-invasive SSDs, aim to substitute one sense for another — in this case hearing for sight. A key finding of the study was that it remains possible for individuals to make use of this substitution even late in life and without any prior experience in visual navigation. "Despite years or a lifetime of blindness," the researchers explain, "the brain has the potential to process visual tasks and properties if the right technologies and training are employed."
The team's work may have an impact beyond allowing the blind to more easily navigate, too: the researchers say that their findings have implications for the detection and even prevention of Alzheimer's disease. "By better understanding the neural mechanisms underlying development and functioning of spatial navigation," the researchers explain, "we may be able to identify early biomarkers and targets for interventions aimed at preventing or slowing the progression of Alzheimer's disease."
The team's work is available in the journal Current Biology under open-access terms.