April 27, 2020

Does Age-Related Hearing Loss Worsen Cognitive Decline?

UCA logo

By Natalie Benafield, Au.D., CCC-A
Communication Sciences and Disorders
University of Central Arkansas

 

Most of us associate aging with a decline in hearing acuity, with good reason. Two-thirds of individuals over 70 years of age have a loss in hearing that would be considered clinically significant. Communication obviously suffers, causing frustration for both the person with the hearing loss and their family members. However, it is estimated that less than one-quarter of individuals with age-related hearing loss seek treatment. Evidence is mounting that ignoring hearing as you age can have detrimental effects that go beyond difficulty communicating with others.

As far back as 1989, scientists have suggested that age-related hearing loss may contribute to cognitive decline in seniors. A pivotal study published in the Journal of the American Medical Association (Uhlmann, et.al.,1989) suggested that hearing loss in older adults was associated with a higher risk of dementia. For the past several years, other researchers have been conducting research in this area and have come to similar conclusions. Dr. Frank Lin, at Johns Hopkins University, and his team followed 639 individuals from the ages of 36-90 for twelve years to investigate the link between hearing loss and dementia. After adjustment for other factors including age, gender, educational level, diabetes, smoking and hypertension, their research suggested that those with hearing loss experiences a 30-40% accelerated rate of cognitive decline (Lin, et al., 2013). More recently a large-scale review of epidemiologic studies of age-related hearing loss and cognitive function from twelve countries was conducted. The researchers found that age-related hearing loss was significantly association with a decline in all main cognitive domains, except for Alzheimer’s disease and vascular dementia. They concluded that hearing loss related to aging is a modifiable risk factor for cognitive decline and dementia in seniors (Loughrey, et al., 2018).

While the exact mechanism underlying the relationship between age-related hearing loss and cognitive decline has not been identified, there are several theories. Some have suggested that hearing loss and cognitive decline may be caused by the same general neurodegenerative process (Stahl, 2017). Neuroimaging studies have suggested that similar changes in the temporal regions of the brain have been noted in individuals with hearing loss and with cognitive decline (Lin, et al., 2014). Other researchers suggest that hearing loss (i.e., the lack of sensory input) causes individuals to use additional cognitive resources to process auditory input, resulting in chronic cognitive “multitasking” and overload. (Tun, McCoy, & Wingfield, 2009). Exacerbating the condition may be that untreated hearing loss often leads to social isolation and even depression, which in turn leads to reduced cortical input over time, hastening atrophy in certain regions of the brain.

Will hearing aid use slow cognitive decline? It makes sense that the use of hearing devices such as hearing aids could increase auditory input, lessen cognitive load, and decrease social isolation, thereby slowing cognitive decline (Sarampalis, et al., 2009). However, we need more large-scale, longitudinal studies before being confident of that claim. Current studies have failed to show a robust protective relationship between hearing aid use and cognitive function. One recent small-scale study found that individuals with evidence of auditory- to- visual cross-modal reorganization in the brain showed evidence of reversal of the re-organization in the auditory cortex, with additional gains in speech perception and cognitive performance (Glick & Sharma, 2020).

What does this mean for current clinical care of older adults? Health care providers often see hearing loss as normal part of aging as they must focus on the numerous urgent medical needs of older adults. This research suggests that clinicians should take a proactive, rather than reactive approach to hearing health in the aging population. Rather than waiting until a patient complains of difficulty hearing, encourage early hearing screening, evaluation, and treatment for those 60 and older. Most patients will not understand the importance of their hearing to brain health. While we lack the evidence to suggest that hearing aids can reduce cognitive decline, we have plenty of evidence to say that hearing loss is not good for the brain. Early hearing evaluation and treatment is risk-free, and evidence is mounting that appropriate treatment of age-related hearing loss could have a positive impact on cognitive decline.

 

References

Glick, H. A., & Sharma, A. (2020). Cortical Neuroplasticity and Cognitive Function in Early-Stage, Mild-Moderate Hearing Loss: Evidence of Neurocognitive Benefit From Hearing Aid Use. Frontiers in Neuroscience, 1.

Lin, F. R., Yaffe, K., Xia, J., Xue, Q.-L., Harris, T. B., Purchase-Helzner, E., Satterfield, S., Ayonayon, H. N., Ferrucci, L., & Simonsick, E. M. (2013). Hearing loss and cognitive decline in older adults. JAMA Internal Medicine173(4), 293–299. https://doi.org/10.1001/jamainternmed.2013.1868

Lin, F. R., & Albert, M. (2014). Hearing loss and dementia – who is listening? Aging & Mental Health18(6), 671–673. https://doi.org/10.1080/13607863.2014.915924

Loughrey, D. G., Kelly, M. E., Kelley, G. A., Brennan, S., & Lawlor, B. A. (2018). Association of Age-Related Hearing Loss With Cognitive Function, Cognitive Impairment, and Dementia: A Systematic Review and Meta-analysis. JAMA Otolaryngology– Head & Neck Surgery144(2), 115–126. https://doi-org.ucark.idm.oclc.org/10.1001/jamaoto.2017.2513

Sarampalis A, Kalluri S, Edwards B, & Hafter E. (2009). Objective measures of listening effort: effects of background noise and noise reduction. Journal of Speech, Language & Hearing Research52(5), 1230–1240. https://doi.org/1092-4388(2009/08-0111)

Tun PA, McCoy S, Wingfield A, Tun, P. A., McCoy, S., & Wingfield, A. (2009). Aging, hearing acuity, and the attentional costs of effortful listening. Psychology & Aging24(3), 761–766. https://doi.org/10.1037/a0014802

Uhlmann, R.F., Larson, E.B., Rees, R.S., Koepsell, T.D., Duckert, L.G. (1989). Relationship of hearing impairment to dementia and cognitive dysfunction in older adults. Journal of the American Medical Association 261(13), 1816-1919.

Weinstein, B.E., (2018). A primer on dementia and hearing loss. Perspectives of the ASHA Special Interest Groups, 3(6), 18-27.