Dementia describes a group of different brain disorders that can trigger a loss of brain function, including memory, thinking, orientation, comprehension, learning capacity, language, and judgment. These conditions are all usually progressive and can eventually become severe.
For a long time, researchers have linked dementia to hearing loss. Both conditions often occur together as we get older, they can have an impact on each other, and sometimes, one can even be misdiagnosed as the other. Scientists and audiologists know that hearing loss and dementia are linked in several ways, and a wealth of research has been conducted to find out how.
Here, we’ll take a closer look at some of the risk factors for dementia development, and explain the importance of regular hearing tests and protection.

Can hearing loss mimic dementia?

Due to the similarity of their symptoms, hearing loss can sometimes be misdiagnosed as dementia, and vice versa. Both have similar symptoms that frequently overlap with each other. For example, a person who has difficulties with communication, speech, and processing speech can be either showing preliminary signs of dementia or simply a case of hearing impairment. It’s also widely known that people with dementia can have difficulty communicating or responding to complex questions — also common with hearing impairment — which is why the two are often confused.

Can hearing loss increase your risk of developing dementia?

A number of research studies show that loss of hearing, especially in older adults, can cause cognitive decline that may lead to dementia. 1,2,3,4 As a result, people with moderate to severe hearing loss are up to five times as likely to develop dementia.5 From brain scan studies, we also know that hearing loss can speed up the onset of dementia or make the symptoms of dementia appear worse.6 

The social impacts of hearing loss may also place individuals at a higher risk of developing dementia. For instance, hearing difficulties may reduce quality of life through social isolation, feelings of loneliness and depression, and a loss of independence. These factors may, in turn, increase the risk of developing dementia.

Can combined hearing and visual impairment increase the risk of developing dementia?

The link between hearing loss and dementia is already widely known. However, recent research suggests that people with both visual and hearing impairment (known as dual sensory impairment) are nearly twice as likely to develop dementia as those without such impairments.9 Another Korean study also shows similar findings.13 Researchers believe that this may be because a decline in both the senses can worsen social isolation, as well as place strain on the parts of the brain needed for good cognitive function.10

More recently, researchers have also been investigating the link between pre-existing eye conditions and dementia, with one study finding an association between Normal-Tension Glaucoma and poor cognition.14

Can wearing hearing aids protect against dementia?

While it’s important to understand that there is no current cure for dementia, researchers are investigating ways to protect against its development. In particular, much of the research has been conducted around hearing aids and protection. 

An international review published in The Lancet Commission suggested that hearing loss is one of nine key risk factors that could be changed to reduce dementia risk. In particular, unaddressed hearing loss in mid-life was predicted to be the highest potentially modifiable risk factor for developing dementia, being potentially responsible for 9% of cases.10 

A more recent review of a number of studies found that correct and consistent hearing aid use was the largest factor protecting against the cognitive decline linked to dementia.11 It is thought that hearing aid use can help to prevent the cognitive decline associated with hearing loss, which could otherwise lead to dementia.
Of course, this does not mean that wearing hearing aids is guaranteed to prevent dementia development. However, it does highlight the importance of regular hearing tests, especially in middle-aged and older adults, to help identify any hearing impairments that may cause problems later on in life. The earlier hearing loss can be identified, the sooner protective measures such as hearing aids can be put in place.

If you’ve noticed a recent change in your hearing, or it’s been a while since your last hearing test, it’s best to have it checked. You can use our free online hearing test tool, or contact your local store to book a hearing test with one of our audiologists.

Dementia resources:

References
  1. Alzheimers.org , Key facts and statistics on dementia (2019). Available at: https://www.alzheimers.org.uk/about-us/news-and-media/facts-media#:~:text=There%20are%20currently%20around%20850%2C000,age%20of%2080%20have%20dementia. [accessed 27/08/20]
  2. Davies HR, Cadar D, Herbert A, Orrell M, Steptoe A. Hearing Impairment and Incident Dementia: Findings from the English Longitudinal Study of Ageing. J Am Geriatr Soc. 2017;65(9):2074-2081. doi:10.1111/jgs.14986
  3. Lin FR, Yaffe K, Xia J, et al. Hearing loss and cognitive decline in older adults. JAMA Intern Med. 2013;173(4):293-299. doi:10.1001/jamainternmed.2013.1868
  4. Hubbard HI, Mamo SK, Hopper T. Dementia and Hearing Loss: Interrelationships and Treatment Considerations. Semin Speech Lang. 2018;39(3):197-210. doi:10.1055/s-0038-1660779
  5. Ford AH, Hankey GJ, Yeap BB, Golledge J, Flicker L, Almeida OP. Hearing loss and the risk of dementia in later life. Maturitas. 2018;112:1-11. doi:10.1016/j.maturitas.2018.03.004
  6. Lin FR, Metter EJ, O'Brien RJ, Resnick SM, Zonderman AB, Ferrucci L. Hearing loss and incident dementia. Arch Neurol. 2011;68(2):214-220. doi:10.1001/archneurol.2010.362
  7. Brenowitz WD, Besser LM, Kukull WA, Keene CD, Glymour MM, Yaffe K. Clinician judged hearing impairment and associations with neuropathologic burden [published online ahead of print, 2020 Aug 5]. Neurology. 
  8.  Davis A, McMahon CM, Pichora-Fuller KM, et al. Aging and Hearing Health: The Life-course Approach. Gerontologist. 2016;56 Suppl 2(Suppl 2):S256-S267. doi:10.1093/geront/gnw033
  9. Hwang PH, Longstreth WT Jr, Brenowitz WD, et al. Dual sensory impairment in older adults and risk of dementia from the GEM Study Alzheimers Dement. (2020). Available at: https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/dad2.12054 [accessed 27/08/20]
  10. Gadkaree SK, Sun DQ, Li C, et al. Does Sensory Function Decline Independently or Concomitantly with Age? Data from the Baltimore Longitudinal Study of Aging. J Aging Res. 2016;2016:1865038. doi:10.1155/2016/1865038
  11. The Lancet Commission, Dementia Prevention, Intervention and Care (2017). Available at: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(17)31363-6/fulltext [accessed 27/08/20]
  12. The Lancet Commission, Dementia Prevention, Intervention and Care (2020). Available at: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30367-6/fulltext [accessed 27/08/20]

Gihwan Byeon, Gyu han Oh, Jin Hyeong Jhoo at al, Dual Sensory Impairment and Cognitive Impairment in the Korean Longitudinal Elderly Cohort (2021). Available at: https://n.neurology.org/content/early/2021/04/07/WNL.0000000000011845 [accessed 14/04/21]

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Treatment of hearing loss
Symptoms of hearing loss