Neuropathological Findings of Dementia Associated With Subjective Hearing Loss.

Objective: The relationship between hearing loss and cognitive decline is of great importance with growing evidence of hearing loss as an independent modifiable risk factor for dementia. Our goal was to evaluate for differences in dementia neuropathology between subjective normal hearing and hearing loss subjects, as well as subjects who wore hearing aids.
Study Design: Retrospective database.
Setting: Tertiary academic center.
Patients: Brain tissue analyzed from our Center on Aging. Demographics, subjective hearing status, hearing aid use, cognitive status, and dementia neuropathology documented.
Interventions: Dementia neuropathology analyzed in brains of normal hearing and hearing loss subjects.
Main Outcome Measures: Differences in dementia neuropathology between hearing groups. Groups were compared using logistic regression and analysis of covariance (ANCOVA).
Results: Two-hundred and seventy-three subjects were included, 189 normal hearing and 84 subjective hearing loss subjects. No significant difference demonstrated in Alzheimer's disease neuropathology (p > 0.05) or pathologic stage (p = 0.2471). No significant difference observed in neuropathology of other major dementia types, specifically, presence of Lewy bodies (p > 0.05), Lewy body disease pathologic stage (p = 0.9778), or presence of micro-infarcts, macro-infarcts, or arteriosclerosis (p > 0.05). Hearing aid-wearing subjects had a lower prevalence of clinical dementia (39.1% versus 57.9%; p = 0.0208) with no significant difference in dementia neuropathology (p > 0.05).
Conclusion: Subjective hearing loss was not found to be associated with significantly different dementia neuropathology, which counters hypotheses on hearing loss causing permanent neurodegeneration and cognitive decline. Hearing aid users were found to have a lower prevalence of dementia for similar levels of neurodegeneration, suggesting a potential neuroprotective effect of hearing aids.