The Connection Between Hearing Loss and Dementia
Hearing loss can manifest as a sudden or gradual change in how well you hear. People with hearing loss may notice difficulties with everyday conversations, especially in noise.
Dementia is a general term for a group of symptoms that impact abilities to think, remember, and reason through activities of daily living. It is a syndrome that can impact memory and thinking abilities, particularly activities of daily living or social functioning. It may affect judgment, problem solving, and even personality.
Cognitive decline is a general term that can be used to describe common effects of brain aging. Even healthy aging may include a slow decline in memory and thinking abilities. Of the early signs of dementia, some minor changes may be expected indications of slight cognitive decline.
It's important to note that most large studies that found this link were based on questionnaires that people fill out. Also, unlike previous research, this study looked objectively at hearing loss and dementia. In this new study, however, the investigative team used an electronic tablet-based audiometer to evaluate participants' hearing for four pure tone frequencies that are most important for understanding speech.
The Increased Risk
Untreated hearing loss increases the risk for dementia (Livingston et al., 2020). Adults with hearing loss have a faster rate of cognitive decline than adults with normal hearing (Lin et al., 2013). Hearing loss is estimated to account for 8% of dementia cases.
Why Hearing Loss May Cause Dementia
This research helps us understand why hearing loss causes dementia. Hearing loss can make the brain work harder, forcing it to strain to hear and fill in the gaps. That comes at the expense of other thinking and memory systems. There are also documented changes in the brain as a result of hearing loss (Lin et al., 2014); these changes are thought to impact cognition over time. Another possibility: Hearing loss causes the aging brain to shrink more quickly.
Hearing loss demands extra cognitive (thinking-related) resources, which limits the cognitive resources that are available for memory and thinking. When there is hearing loss, auditory stimulation is reduced. This, by itself, likely increases dementia risk. But even more important is that when an individual suffers from moderate to severe hearing loss, they are less likely to participate in social activities. Perhaps they are embarrassed about their hearing loss. A third possibility is that hearing loss leads people to be less socially engaged, which is hugely important to remaining intellectually stimulated.
It turns out that social activities are one of the best ways to stimulate the brain, as there is evidence that our brains evolved to facilitate social behavior. Additionally, hearing loss can lead to a decrease in social engagement (Weinstein & Ventry, JSHR, 1982), which is a known risk factor of dementia. Given all this information, you won't be surprised to learn that reduced social activity has been linked to cognitive decline.
The Role of Hearing Aids
Hearing aids are a type of amplification device used to manage hearing loss. Recent research indicates that for people at greater risk of developing dementia, using appropriately fitted hearing aids reduces the risk of cognitive decline as compared to people who are high risk and who did not use hearing aids in the same 3-year period (Lin et al., 2023).
Properly fit hearing aids are known to reduce listening effort, allowing for more cognitive resources to be available for other brain tasks. Hearing aids can also re-stimulate areas of the brain that have been neglected due to hearing loss. Lastly, hearing aids are known to improve social communication, which may prevent or delay dementia.
For patients diagnosed with dementia, hearing loss should be considered and treated. In early dementia, and with patients who have in-tact support systems, hearing aids may still be a good treatment option. For patients without the option of hearing aids, there are other assistive listening devices that could be helpful, such as remote microphones.
Taking Action
Many communication difficulties related to hearing loss can cross-over with difficulties related to dementia. If adults are uncertain which dysfunction may be causing difficulties, it is recommended to seek evaluation from an audiologist (for hearing) and a physician.
Keep your ears clean. (But remember, never put anything in your ears smaller than your elbow. If you can't hear and you don't have hearing aids, get them. All these things will help to reduce your risk of dementia.
Suspect Hearing Loss?
If you are concerned about hearing loss, the next step is to schedule a hearing test with an audiologist. The audiologist will be able to determine presence, type, and severity of hearing loss.
References:
- Lin FR, Yaffe K, Xia J, Xue QL, et al. (2013) Hearing loss and cognitive decline in older adults.
- Lin FR, Ferrucci L, An Y, Goh JO, et al. (2014) Association of hearing impairment with brain volume changes in older adults.
- Lin, F. R., Pike, J. R., Albert, M. S., Arnold, M., Burgard, S., Chisolm, T., Couper, D., Deal, J. A., Goman, A. M., Glynn, N. W., Gmelin, T., Gravens-Mueller, L., Hayden, K. M., Huang, A. R., Knopman, D., Mitchell, C. M., Mosley, T., Pankow, J. S., Reed, N. S., Sanchez, V., … ACHIEVE Collaborative Research Group (2023). Hearing intervention versus health education control to reduce cognitive decline in older adults with hearing loss in the USA (ACHIEVE): a multicentre, randomised controlled trial. The Lancet 402(10404): 786-797.
- Livingston G, Huntley J, Sommerlad A, Ames D, et al. (2020) Dementia prevention, intervention, and care: 2020 report of the Lancet Commission.
- MIND Center (2019)Navigating Alzheimer’s and Related Dementias: A Roadmap for Families.
- Weinstein BE, Ventry IM. (1982) Hearing impairment and social isolation in the elderly.