Both scientific studies and anecdotal findings suggest that individuals experiencing vision loss develop a stronger sense of hearing. But what exactly happens in the brain during this process? Recent research seeks to answer this question.
According to the World Health Organization (WHO), an estimated 1.3 billion people worldwide have some form of visual impairment, ranging from mild vision loss to permanent blindness.
Individuals who experience partial or complete vision loss tend to have heightened tactile and auditory senses compared to those with normal vision. This is because they must rely more on their other senses to navigate their surroundings.
Researchers have found that individuals with severe visual impairments perform better in tasks related to hearing and determining the direction of sounds. Other studies have revealed that individuals who lose their sense of sight early in life tend to have better auditory abilities than their sighted counterparts.
Previous research indicates that the brains of individuals experiencing vision loss can adapt and reconfigure neural networks to enhance the function of other senses. Scientists from Washington and Oxford Universities observed changes in the brains of individuals who lost their vision early in life, leading to better auditory perception. The findings were published in The Journal of Neuroscience, where the researchers investigated what happens in the auditory cortex of the brain.
Changes in the Auditory Cortex:
Existing studies show that in cases of early-onset visual impairments, the occipital cortex (the part of the brain that processes visual information from the eyes) adapts to process information from other parts of the body. However, Kelly Chang and her colleagues, the authors of the study, observed that the auditory cortex also adapts to process sound differently, compensating for the loss of vision.
In a new study, Chang and her team compared changes in individuals with anophthalmia (congenital absence of eyes) to those with normal vision. The researchers examined the participants' brains using functional MRI scans. During the scans, participants were exposed to sounds of different frequencies, and the analysis focused on what occurred in their auditory cortices. The results showed that, despite having auditory cortices of similar sizes, individuals with vision loss were better at perceiving sounds at specific frequencies.
These findings shed light on how individuals who lose their sense of sight early in life adapt to vision loss and why their auditory senses become more developed. In the future, Chang and her colleagues aim to investigate what happens in the brains of individuals who lose their vision later in life and those who regain their vision. Scientists hope that such research will contribute to a better understanding of the system that allows the brain to adapt to changes in the five senses.