Why and how are dementia and hearing loss linked? Our Audiologist explains the latest research - Action On Hearing Loss: RNID
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Why and how are dementia and hearing loss linked? Our Audiologist explains the latest research

Posted on: Tuesday, August 1, 2017 by Katy Bugg

Vaitheki MaheswaranAn international study on the link between hearing loss and dementia has attracted much attention in the last months. Due to the increasing interest and the concerns of some of our readers, Action on Hearing Loss Audiologist Specialist Vaitheki Maheswaran reviews the latest research on the topic.

According to an international study in the Lancet, it is estimated that there were 46·8 million people living with dementia worldwide in 2015, which is likely to increase to 131·5 million by 2050. 58% of people with dementia live in low income and middle income countries. It is expected for numbers affected by dementia to double in high-income countries but more than treble in low and middle-income countries by 2050.

This research shows that one in three cases of dementia could be prevented if more people looked after their brain health throughout life. Nine key risk factors thought to contribute to the risk of dementia have come to light, including: education to a maximum of age 11–12 years, midlife hypertension, midlife obesity, hearing loss, late life depression, diabetes, physical inactivity, smoking, and social isolation. These risk factors, which are described as possibly modifiable (factors which can be changed to reduce dementia risk), make up 35%. The other 65% of dementia risk is thought to be potentially non-modifiable (factors which cannot be changed).

What is the link between hearing loss and dementia?

Over the last few years, there is growing evidence of a link between dementia/cognition and hearing loss. Hearing loss and dementia are linked with ageing and often occur together as we get older - the majority of people with dementia are over 70 and nearly three quarters of people over 70 have hearing loss. There is strong evidence that mild hearing loss doubles the risk of developing dementia, with moderate hearing loss leading to three times the risk, and severe hearing loss five times the risk. Hearing loss can be misdiagnosed as dementia or make the symptoms of dementia appear worse.

Common symptoms of dementia:

  • Memory loss

  • Confusion (not remembering what they were saying)

  • Difficulty with thinking and decision making (should they answer the door?)

  • Decline in skills needed for everyday living (not remembering how to cook)

  • Changes in ways of communicating (not being able to find the correct word, mixing up words, or repeating what’s been said)

Common symptoms of hearing loss:

  • Difficulty hearing other people clearly and misunderstanding what they say, especially in group situations

  • Asking people to repeat themselves and/or speak more slowly

  • Having the volume for music/TV higher than other people need

  • Difficulty hearing the phone/doorbell

  • Finding it difficult to tell which direction noise is coming from

  • Often feeling tired or stressed, from having to concentrate while listening.

People with dementia can have difficulty communicating with others, including finding the right words, or signs, for what they want to say. They will have difficulty processing what they’ve heard, particularly if there are distractions. According to some researchers, this difficulty in processing information (when there is competing information, auditory or otherwise) can be one of the first signs of some form of cognitive impairment.

Further evidence suggests that proper diagnosis and management of hearing loss, including provision of hearing aids, reduce the risk and impact of dementia and some of the other associated co-morbidities, such as falls and depression.

It is worth noting that although dementia is diagnosed in later life, changes in the brain usually start developing many years before. The study looked at the benefits of building a "cognitive reserve", meaning that if the brain’s networks were strengthened, it could continue to function in later life regardless of the damage. As discussed, lifestyle factors can play a vital role in increasing or reducing an individual's dementia risk. It is suggested that not smoking, keeping healthy, doing exercise and treating high blood pressure and diabetes can all help reduce the risk of dementia for some, as well as cardiovascular disease.
It is important to remember that not everyone will successfully make changes; some changes will not make a difference and some risks of dementia are hereditary and cannot be changed. If you are worried about hearing loss or dementia, it is best to speak to your GP who will then refer you to the appropriate professional for further investigation, for example an audiologist or ENT Consultant for hearing difficulties.

We recommend people get their hearing tested and, if they have hearing loss, to get hearing aids, as the evidence suggests that they can help reduce the risk of dementia and its impact.

 

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