hearing-loss-and-dementia.
Hearing loss in midlife has been estimated to account for 9% of cases of dementia, a huge (but potentially reversible) disease burden given that dementia affects 47 million people worldwide (Livingston et al., 2017). Acquired hearing loss is most commonly caused by cochlear damage, while dementia is due to cortical degeneration that typically begins in multimodal cortex. This immediately begs the question of how the two are linked. This is a crucial question from a theoretical perspective, as there are multiple biological and psychological pathways that may link peripheral auditory function to broad-based cortical changes associated with dementia. It also has critical practical implications because while it is difficult, if not impossible, to remediate cortical degradation, hearing loss is widely treatable with hearing aids or cochlear implants. Thus, an understanding of the mechanisms linking the two could have wide-ranging public health importance.
A new study led by researchers at the Johns Hopkins Bloomberg School of Public Health found that older adults with greater severity of hearing loss were more likely to have dementia, but the likelihood of dementia was lower among hearing aid users compared to non-users. The findings, from a nationally representative sample of more than 2,400 older adults, are consistent with prior studies showing that hearing loss might be a contributing factor to dementia risk over time, and that treating hearing loss may lower dementia risk. The findings are highlighted in a research letter published online January 10 in the Journal of the American Medical Association. “This study refines what we’ve observed about the link between hearing loss and dementia, and builds support for public health action to improve hearing care access,” says lead author Alison Huang, PhD, MPH, a senior research associate in the Bloomberg School’s Department of Epidemiology and at the Cochlear Center for Hearing and Public Health, also at the Bloomberg School.