018-22 – The impact of age-related hearing loss on structural neuroanatomy: a meta-analysis

This meta-analysis investigated the association between age-related hearing loss and structural neuroanatomy, specifically changes to grey matter volume. Hearing loss is associated with increased risk of cognitive decline. Hence, understanding the effects of hearing loss in older age on brain health is essential. We reviewed studies which compared older participants with hearing loss (HL) to older adults without clinical hearing loss (NH), on neuroanatomical outcomes, specifically grey matter volume as measured by magnetic resonance imaging. A total of five studies met the inclusion criteria, three of which were included in an analysis of whole-brain grey matter volume (HL-group n = 113; NH-group n = 138), and three were included in analyses of lobe wise grey matter volume (HL-group n = 139; NH-group n = 162). Effect-size seed-based d mapping software was employed for whole-brain and lobe-wise analysis of grey matter volume. The analysis indicated there was no significant difference between older adults with HL compared to those with no age-related HL in whole-brain grey matter volume. Due to lacking stereotactic coordinates, the atrophy of grey matter in specific neural locations could only be conducted at lobe-level. These data indicate that older adults with HL show increased grey matter atrophy in the temporal lobe only (not in occipital, parietal, or frontal), compared to older adults without HL. The implications for theoretical frameworks of the HL and cognitive decline relationship are discussed in relation to the results. Overall, the findings endorse regular auditory testing for ≥60-year-olds, as HL co-occurred with atrophy in grey matter. Managing age-related HL, e.g., through hearing aids, may reduce the adverse functional effects of grey matter atrophy. This meta-analysis was pre-registered on PROSPERO, available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021265375