Impact of Age-Related Hearing Loss on Brain Connectivity and Cognitive Performance: A Systematic Review.

Adult-onset hearing loss is associated with cognitive decline, although the mechanisms underlying this relationship remain unclear. Emerging evidence suggests that the early stages of hearing loss can alter brain network dynamics, which may be detectable before other neurocognitive markers. This systematic review aims to present evidence for altered brain connectivity in age-related hearing loss, and its subsequent relationship with cognitive performance. The review was preregistered in the Prospective Register of Systematic Reviews and conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We screened 203 articles from 4 databases, of which 25 cohort and case-control studies published between 2019 and 2025 met the inclusion criteria. According to the Newcastle-Ottawa Scale, 76% of the included studies were classified as high methodological quality. The findings show that older adults with age-related hearing loss exhibit changes in brain connectivity. A novel finding is the disruption of higher-order networks, such as the Default Mode Network, and its association with reduced performance in cognitive control functions, particularly shifting. This may shed light on the association between hearing loss and cognitive decline, although causality has yet to be established. These findings suggest that brain connectivity may serve as an early neural correlate of cognitive vulnerability and inform future research into interventions targeting cognitive decline.