Hearing Impairment and Cognition in an Aging World.

With the increasing number of older adults around the world, the overall number of dementia cases is expected to rise dramatically in the next 40 years. In 2020, nearly 6 million individuals in the USA were living with Alzheimer's disease, the most common type of dementia, with anticipated growth to nearly 14 million by year 2050. This increasing prevalence, coupled with high societal burden, makes prevention and intervention of dementia a medical and public health priority. As clinicians and researchers, we will continue to see more individuals with hearing loss with other comorbidities including dementia. Epidemiologic evidence suggests an association between hearing loss and increased risk of dementia, presenting opportunity for targeted intervention for hearing loss to play a fundamental role in dementia prevention. In this discussion, we summarize current research on the association between hearing loss and dementia and review potential casual mechanisms behind the association (e.g., sensory-deprivation hypothesis, information-degradation hypothesis, common cause). We emphasize key areas of research which might best inform our investigation of this potential casual association. These selected research priorities include examination of the causal mechanism, measurement of co-existing hearing loss and cognitive impairment, and potential of aural rehabilitation. Addressing these research gaps and how results are then translated for clinical use is paramount for dementia prevention and overall health of older adults.