Time course of visual plasticity following adult-onset deafness.

Abstract

When deprived of a sensory modality, the brain often compensates with supranormal performance in other intact systems. While this compensatory plasticity is typically attributed to early sensory loss, plasticity following adult-onset sensory loss remains poorly understood despite its clinical relevance. In many patients, adult-onset hearing loss precedes treatment by cochlear implantation, yet little is known about the neural changes occurring before this intervention. The present study examines this transitional stage using a well-established adult cat model to examine visual plasticity after hearing loss in adulthood. We employed motion-onset visually evoked potentials (VEPs), a technique validated in our previous studies, to examine compensatory neural changes over time. VEPs are widely used in human neurophysiology and offer a translational bridge between basic science and clinical research. Over a 400-day period post adult-onset deafness, we observed gradual amplification in VEP signal power and P1 amplitude, alongside shortened peak latency. Our findings provide evidence that adult-onset deafness can induce compensatory visual plasticity and highlights VEPs as a promising biomarker for tracking such changes. This exploratory study establishes a platform for future research examining post-deafness intervention, such as cochlear implantation.