Hearing loss is associated with gray matter differences in older adults at risk for and with Alzheimer’s disease

Hearing loss in healthy older adults is associated with accelerated brain volume loss; however, little is known about this association in those with or at risk for dementia. Using data from the COMPASS-ND study we investigated associations between hearing loss and hippocampal volume as well as cortical thickness in older adults with subjective cognitive decline (SCD, N=35), mild cognitive impairment (MCI, N=79), and Alzheimer’s dementia (AD, N=21). SCD participants with greater pure-tone hearing loss exhibited lower hippocampal volume, a biomarker of dementia. They also showed more cortical thickness in the left superior temporal gyrus and right pars opercularis, suggesting compensatory cortical changes. No significant associations were found in those with cognitive impairment (MCI or AD) who had greater brain atrophy, suggesting that dementia-related neuropathology may supercede any effects of pure-tone hearing loss on brain volume loss. In contrast, greater speech-in-noise reception thresholds were associated with lower cortical thickness bilaterally across much of the cortex in AD. The AD group also showed worse speech-in-noise thresholds compared to the SCD group, suggesting that strong brain atrophy driven by dementia-related neuropathology in AD is associated with hearing problems in noisy environments. Highlights In older adults with subjective cognitive complaints, greater pure-tone hearing loss was associated with lower hippocampal volume. Pure-tone hearing loss was not associated with brain atrophy in older adults with cognitive impairment (i.e., MCI or AD). Older adults with Alzheimer’s dementia exhibited higher speech-in-noise thresholds than older adults without cognitive impairment. In older adults with Alzheimer’s dementia, greater brain atrophy across large portions of the cortex was associated with greater speech-in-noise thresholds.