Hearing function moderates age-related changes in brain morphometry in the HCP Aging cohort

IntroductionThere are well-established relationships between aging and neurodegenerative changes, and between aging and hearing loss. The goal of this study was to determine how structural brain aging is influenced by hearing loss. MethodsHuman Connectome Project Aging (HCP-A) data were analyzed, including T1-weighted MRI and Words in Noise (WIN) thresholds (n=623). Freesurfer extracted gray and white matter volume, and cortical thickness, area, and curvature. Linear regression models targeted (1) interactions between age and WIN threshold and (2) correlations with WIN threshold adjusted for age, both corrected for false discovery rate (pFDR<0.05). ResultsWIN threshold moderated age-related increase in volume in bilateral inferior lateral ventricles, with higher threshold associated with increased age-related ventricle expansion. Age-related deterioration in occipital cortex was also increased with higher WIN thresholds. When controlling for age, high WIN threshold was correlated with reduced cortical thickness in Heschls gyrus, calcarine sulcus, and other sensory regions, and reduced temporal lobe white matter. Older volunteers with poorer hearing and cognitive scores had the lowest volume in left parahippocampal white matter. ConclusionsPreserved hearing abilities in aging associated with a reduction of age-related changes to medial temporal lobe, and preserved hearing at any age associated with preserved cortical tissue in auditory and other sensory regions. Future longitudinal studies are needed to assess the causal nature of these relationships, but these results indicate interventions which preserve hearing function may combat some neurodegenerative changes in aging. KEY POINTS (3 summarizing key messages)O_LIPoorer hearing was associated with increased age-related ventricle expansion in medial temporal lobes, and reduced temporal lobe white matter at any age. C_LIO_LIPoorer hearing was associated with thinner cortex in Heschls gyrus thickness, calcarine sulcus, and other sensory regions. C_LIO_LIPreserving hearing may reduce brain aging in medial temporal lobe. C_LI