White matter integrity of hearing and cognitive impairments in healthy aging

Age-Related Hearing Loss (ARHL), or presbycusis, affects two-thirds of U.S. adults over 70 and is linked to cognitive decline and an increased risk of dementia. This study examines associations between white matter integrity and hearing and cognitive function in healthy aging using diffusion tensor imaging (DTI). We recruited 126 participants (92 female) aged 20-79 years (Mean = 51.34, SD = 20.54) from the Aging Brain Cohort Study at the University of South Carolina (ABC@UofSC). Cognitive performance was assessed using the Montreal Cognitive Assessment (MoCA), and hearing was evaluated through pure-tone thresholds (PTT) and words-in-noise (WIN) thresholds. White matter integrity was measured with fractional anisotropy (FA) and mean diffusivity (MD), and analyses examined relationships between these DTI metrics and hearing and cognitive scores using the region-of-interest regression analysis. Results showed significant associations between lower FA and higher MD values and poorer hearing and cognitive performance, particularly in the anterior and superior corona radiata, corpus callosum, and superior longitudinal fasciculus. Additionally, ANOVA comparisons between older adults with and without hearing impairments revealed significant MD differences in several regions, indicating specific microstructural changes linked to auditory impairment. This study contributes to the understanding of the neural bases of hearing and cognitive impairments, underscoring the potential of DTI as a complementary tool to gray matter-based studies in exploring reliable imaging evidence of hearing and cognitive impairments in healthy aging across adulthood.