Exploring gray matter volume atrophy associations with hearing in the UK Biobank

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AbstractBackgroundHearing impairment was recently recognized as a modifiable risk factor for dementia. Theories to explain this relationship propose that hearing impairment results in reduced sensory input across the brain, which negatively affects brain structure. Therefore, large exploratory studies are needed to examine potential relationships between hearing and brain volume.Method2,000 participants (age = 63±7 years, 50% female) from the UK Biobank were include in this study. Voxelwise multiple regression models examined the association between hearing and baseline MRI gray matter volume. Hearing was assessed using a speech‐in‐noise task, with positive scores reflecting poorer hearing. Interactions between hearing and sex on brain volume were also explored. Covariates included age, sex (except in model with sex interaction), socioeconomic status, and total intracranial volume. Given the exploratory aim of the analysis, a threshold of p<0.001 was used.ResultThe multiple regression model results showed that poorer hearing is associated with lower gray matter volume in bilateral temporal auditory regions (Heschl’s gyrus, superior temporal gyrus) and left amygdala. While hearing scores did not significantly differ by sex, there were significant hearing‐by‐sex interactions. In women, poorer hearing was associated with lower volume in bilateral auditory regions. In men, poorer hearing was associated with lower volume in right hippocampus and higher volume in posterior cingulate cortex.ConclusionThis study sought to address a major gap in the current literature and explored voxelwise associations between hearing and brain volume in a large sample. The results show that poorer hearing is associated with lower brain volume in lateral and medial temporal regions, which differed by sex. Poorer hearing in women was associated with lower volume in auditory regions, while in men, poorer hearing was associated with lower volume in regions similarly affected by Alzheimer’s disease and dementia. Together, these data provide support for a potential mechanistic explanation for the association between hearing loss and dementia through increased brain atrophy.