Alzheimer’s disease is the most common form of dementia, affecting 6.9 million Americans over age 65.1 This brain condition develops gradually over time, and causes memory loss, confusion, and other signs of cognitive decline. Alzheimer’s disease is also strongly linked to hearing loss.
In this guide, we explore the link between hearing loss and Alzheimer’s disease, and the importance of early detection and treatment in protecting cognitive health.
What is Alzheimer’s Disease?
Alzheimer’s disease is a progressive brain disorder that slowly destroys essential brain functions. It’s the most common form of dementia, and can cause symptoms like mood swings, changes in behavior, memory loss, confusion, difficulty speaking, and more.
While the root cause of Alzheimer’s is not fully understood, scientists believe that for most people, the disease develops gradually over time due to a combination of genetic, lifestyle, and environmental factors.
One of the most prominent hallmarks of Alzheimer’s disease is protein buildup in the brain.2 While these proteins have important functions in the body, excessive buildup kills brain cells, causing brain tissue to shrink over time, leading to Alzheimer’s disease.
But where does hearing loss come into play? Read on to learn more.
Hearing Loss and the Increased Risk of Alzheimer’s Disease
Hearing health is recognized as a significant factor in maintaining long-term brain health. In recent years, researchers have uncovered a strong connection between untreated hearing loss and an increased risk of cognitive decline, including Alzheimer’s disease and other forms of dementia.3
Research shows that moderate hearing loss triples the likelihood of dementia in older adults, while severe hearing loss increases the risk by five times.3 In fact, for adults between 45 and 65, hearing loss is the largest treatable risk factor for dementia.4
Hearing loss and Alzheimer’s disease also share many of the same underlying risk factors, including aging, cardiovascular disease, diabetes, and chronic inflammation. Poor circulation and vascular damage can affect both the inner ear and the brain, making it difficult to separate where one condition begins and the other ends.
Below, we explore the impact untreated hearing loss has on the brain and the factors that can contribute to the increased risk of Alzheimer’s disease in older adults.
Brain Tissue Shrinkage
Over the past decade, scientists have uncovered a strong and growing body of evidence linking hearing loss to cognitive decline and Alzheimer’s disease. Brain imaging studies out of Johns Hopkins have revealed physical changes that may help explain this link.
While our brains naturally shrink with age, MRI scans show that adults with untreated hearing loss tend to have faster rates of brain tissue shrinkage.5 The study concluded that the adults with hearing loss experienced an extra cubic centimeter of brain tissue loss every year.
But why exactly? This research suggests that a lack of auditory stimulation could be a major factor.
Reduced Auditory Stimulation
Just like your muscles need exercise to stay strong, your brain needs regular stimulation to stay active and healthy. When hearing loss goes untreated, the brain receives less auditory stimulation, and neural activity in the temporal lobe can decrease. The temporal lobe is the area of the brain responsible for processing sound and language, as well as key aspects of memory.
The results of the Johns Hopkins study suggest that this reduced auditory stimulation due to untreated hearing can accelerate brain tissue atrophy.5 This in turn, increases the likelihood of cognitive decline and Alzheimer’s disease.
Cognitive Strain
Cognitive strain is the increased effort the brain expends to process and understand sounds due to hearing loss. When the brain needs to work harder to interpret speech, separate it from background noise, and fill in any gaps, it diverts mental resources away from other cognitive functions like memory and attention.
Research shows that over time, this cognitive strain can contribute to listening fatigue and increase the risk of brain conditions like Alzheimer’s disease. 6
Psychological Stress
Psychological stress refers to mental and emotional strain, both of which are associated with hearing loss and also play a role in the risk of Alzheimer’s disease.
Constantly straining to hear can make daily life feel exhausting and isolating. Even activities that were once enjoyable may become sources of frustration. This can contribute to long-term psychological stress.
Over time, stress hormones like cortisol can increase the production of harmful proteins that are linked to Alzheimer’s.7 This means that stress not only contributes to the development of Alzheimer’s but can also drive its progression and make symptoms worse.8
Social Isolation
Social engagement is essential for a healthy, active brain, especially as we age. However, research shows that loneliness and social isolation are incredibly common in older adults with hearing loss.9 Scary still, studies have also found that social isolation can increase the risk of dementia by 50% in older adults.10
Researchers believe that one of the key reasons this happens is due to the lack of auditory stimulation.10 As we mentioned earlier, your brain needs regular stimulation to stay active and healthy. When people spend more time alone, the brain receives less auditory stimulation, increasing the risk of cognitive decline and conditions like Alzheimer’s disease.
Protect Your Cognitive Health: Schedule a Hearing Exam Today
Alzheimer’s disease is a type of dementia that is strongly linked to hearing loss. One of the best things you can do for both your ears and your brain is to catch hearing loss as early as possible. Timely diagnosis and intervention can help safeguard the brain’s ability to process sound and slow the progression of cognitive decline.
By investing in your hearing health, you’re investing in your overall well-being. Find an Audibel clinic near you today to take the first step toward safeguarding your health and quality of life for years to come.
References
- 2024 Alzheimer’s disease facts and figures. (2024). Alzheimer S & Dementia, 20(5), 3708–3821. https://doi.org/10.1002/alz.13809
- What happens to the brain in Alzheimer’s disease? (2024, January 19). National Institute on Aging. https://www.nia.nih.gov/health/alzheimers-causes-and-risk-factors/what-happens-brain-alzheimers-disease
- Huang, A. R., Jiang, K., Lin, F. R., Deal, J. A., & Reed, N. S. (n.d.). Hearing Loss and Dementia Prevalence in Older Adults in the US. JAMA, 329(2), 171. https://doi.org/10.1001/jama.2022.20954
- Livingston, G., Huntley, J., Sommerlad, A., Ames, D., Ballard, C., Banerjee, S., Brayne, C., Burns, A., Cohen-Mansfield, J., Cooper, C., Costafreda, S. G., Dias, A., Fox, N., Gitlin, L. N., Howard, R., Kales, H. C., Kivimäki, M., Larson, E. B., Ogunniyi, A., . . . Mukadam, N. (n.d.). Dementia prevention, intervention, and care: 2020 report of the Lancet Commission. The Lancet, 396(10248), 413–446. https://doi.org/10.1016/s0140-6736(20)30367-6
- Armstrong, N. M., An, Y., Doshi, J., Erus, G., Ferrucci, L., Davatzikos, C., Deal, J. A., Lin, F. R., & Resnick, S. M. (n.d.-b). Association of Midlife Hearing Impairment With Late-Life Temporal Lobe Volume Loss. JAMA Otolaryngology–Head & Neck Surgery, 145(9), 794. https://doi.org/10.1001/jamaoto.2019.1610
- Bisogno, A., Scarpa, A., Di Girolamo, S., De Luca, P., Cassandro, C., Viola, P., Ricciardiello, F., Greco, A., De Vincentiis, M., Ralli, M., & Di Stadio, A. (2021). Hearing loss and Cognitive impairment: Epidemiology, common pathophysiological findings, and treatment considerations. Life, 11(10), 1102. https://doi.org/10.3390/life11101102
- Dong, H., & Csernansky, J. G. (2009b). Effects of stress and stress hormones on amyloid-Β protein and plaque deposition. Journal of Alzheimer S Disease, 18(2), 459–469. https://pmc.ncbi.nlm.nih.gov/articles/PMC2905685/
- Justice, N. J. (2018). The relationship between stress and Alzheimer’s disease. Neurobiology of Stress, 8, 127–133. https://doi.org/10.1016/j.ynstr.2018.04.002
- Shukla, A., Harper, M., Pedersen, E., Goman, A., Suen, J. J., Price, C., Applebaum, J., Hoyer, M., Lin, F. R., & Reed, N. S. (2020). Hearing Loss, Loneliness, and Social Isolation: A Systematic review. Otolaryngology, 162(5), 622–633. https://doi.org/10.1177/0194599820910377
- Guarnera, J., Yuen, E., & Macpherson, H. (2023). The Impact of loneliness and social isolation on Cognitive aging: A Narrative review. Journal of Alzheimer S Disease Reports, 7(1), 699–714. https://doi.org/10.3233/adr-230011
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