Public Health

Area of Science:

• Neurology
• Gerontology
• Public Health

Background:

• Hearing loss is a known risk factor for dementia.
• The mechanisms linking hearing loss to dementia and the protective effects of hearing aids are not fully understood.
• Community-based studies examining hearing, hearing aid use, and brain autopsy neuropathology are limited.

Purpose of the Study:

• To investigate the association between hearing impairment, hearing aid use, and neuropathologic features in older adults.
• To explore differences in neuropathologic profiles (Alzheimer's disease neuropathologic change, Lewy body disease, hippocampal sclerosis, vascular brain injury) between individuals with and without hearing impairment.

Main Methods:

• Analysis of autopsy and clinical hearing history data from 850 participants (≥65 years) in the Adult Changes in Thought study.
• Determination of hearing impairment and hearing aid use via medical record review.
• Logistic regression models used to assess associations, adjusting for covariates; relative risks (RR) estimated using marginal standardization.

Main Results:

• 67.1% of participants had documented hearing loss; 36.8% used hearing aids.
• Hearing loss was associated with hippocampal sclerosis (RR: 1.13; 95% CI: 1.003, 1.28).
• Hearing aid use was associated with lower Alzheimer's disease neuropathologic change (ADNC) scores (RR per unit increment: 0.94; 95% CI: 0.89, 0.99).

Conclusions:

• Clinically diagnosed hearing loss in this cohort was linked to hippocampal sclerosis but not other examined neuropathologies.
• Hearing aid use showed an association with reduced levels of ADNC.
• Further research is required to confirm these findings and elucidate the causal pathways involved.