The Association Between Early Age-Related Hearing Loss and Brain β-Amyloid

Abstract

Objectives/hypothesis: To analyze the association between early audiometric age-related hearing loss and brain β-amyloid, the pathologic hallmark of Alzheimer's disease (AD).

Study design: Cross-sectional analysis of a prospective cohort study.

Methods: A cross-sectional analysis was performed on 98 participants in a cohort study of hearing and brain biomarkers of AD. The primary outcome was whole brain β-amyloid standardized uptake value ratio (SUVR) on positron emission tomography (PET). The exposure was hearing, as measured by either pure-tone average or word recognition score in the better ear. Covariates included age, gender, education, cardiovascular disease, and hearing aid use. Linear regression was performed to analyze the association between β-amyloid and hearing, adjusting for potentially confounding covariates.

Results: The mean age ± standard deviation was 64.6 ± 3.5 years. In multivariable regression, adjusting for demographics, education, cardiovascular disease, and hearing aid use, whole brain β-amyloid SUVR increased by 0.029 (95% confidence interval [CI]: 0.003-0.056) for every 10 dB increase in pure-tone average (P = .030). Similarly, whole brain β-amyloid SUVR increased by 0.061 (95% CI: 0.009-0.112) for every 10% increase in word recognition score (P = .012).

Conclusions: Worsening hearing was associated with higher β-amyloid burden, a pathologic hallmark of AD, measured in vivo with PET scans.

Level of evidence: 3 Laryngoscope, 131:633-638, 2021.

Keywords: Age-related hearing loss; cognition; dementia; presbycusis; β-amyloid.

Figure 1.

Flow diagram indicating subject inclusion and exclusion.

Figure 2.

Scatterplots depicting the distribution and relationship of hearing versus age. Points represent individual subjects, with overlapping points indicated by darker coloration. A univariable regression line (blue) and 95% confidence interval (gray shading) are overlaid. (a) Pure tone average in the better hearing ear versus age. (b) Word recognition score in the better hearing ear versus age.

Figure 3.

Univariable linear regression models of global brain beta-amyloid standardized uptake value ratio (SUVR) based on hearing. The univariable regression line (blue) and 95% confidence interval (gray shading) are overlaid. (a) Global brain beta-amyloid versus pure tone average in the better ear. (b) Global brain beta-amyloid versus wore recognition score in the better rear.