PNAS: Early Deafness Changes Brain Function and Enhances Peripheral Vision

A study by researchers from the universities of Sheffield and York has shown that in people with early-onset profound hearing loss, the brain reallocates resources involved in processing visual information. As a result, peripheral vision, which allows people to detect movement and events outside the central part of the visual field, is better represented.

The researchers studied 32 adults: 16 participants with early-onset profound deafness and 16 hearing participants of approximately the same age. Using functional MRI, the scientists examined how different areas of the brain represent different parts of the visual field.

The study, published in the journal Proceedings of the National Academy of Sciences, found that a greater proportion of neural resources in deaf participants was devoted to the far periphery of the visual field. This was observed both in the primary visual cortex and in the lateral geniculate nucleus, a brain structure that transmits visual information from the retina to the cortex.

At the same time, the brain did not increase its overall capacity to process visual information. Instead, the resources were redistributed: peripheral vision received a relatively greater share of neural resources, while a smaller share was devoted to the central visual field.

According to Professor Charlotte Codina of the University of Sheffield, the findings demonstrate how strongly the brain can adapt to changes in the sensory environment. Such reorganization may help people with early-onset deafness detect movement or potential threats outside the center of their visual field more effectively.

The authors note that the study provides further insight into neuroplasticity — the brain’s ability to alter the organization and allocation of its resources in response to differences in sensory experience.

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