The impact of hearing impairment and hearing aid use on progression to mild cognitive impairment in cognitively healthy adults: a longitudinal study of 5721 participants
Abstract The increasing prevalence of dementia in older adults warrants attention to the identification of practices that can delay or reduce likelihood of progression to early forms of cognitive impairment, in particular, to mild cognitive impairment (MCI) which is often considered a transitional stage between healthy aging and dementia. In this study, we investigated the effect of hearing impairment and hearing aid usage on cognitive decline and progression to MCI in cognitively healthy individuals. We used data from a large referral-based cohort obtained from the National Alzheimer’s Coordinating Center. The baseline sample included 5721 cognitively normal subjects aged ≥ 40. We found that hearing impairment was associated with increased risk of progression to MCI (hazard ratio [HR] = 1.40, 95%CI, 1.16-1.68, false discovery rate [FDR] P < 0.001) and an accelerated rate of cognitive decline (P < 0.001). Among hearing-impaired participants, hearing aid users were less likely to develop MCI (HR, 0.33; 95% CI, 0.23-0.47; FDR P < 0.001) and experienced slower cognitive decline (P = 0.004) when compared to those not using hearing aids. We found no statistically significant differences in risk of conversion to MCI between individuals with normal hearing and hearing-impaired adults using hearing aids (HR, 1.23; 95% CI, 0.99-1.50; FDR P = 0.08). Our findings highlight the need for a randomized clinical trial that will allow us to investigate whether there is a causal relationship between hearing loss, hearing aid use, and conversion to MCI. Such knowledge could provide new and novel insights into prevention of cognitive impairment and dementia.