Hearing loss & Dementia – Is there a link?

June 4th, 2018

­­­­­­­­­­­­­­­­If you were to make a list of health conditions and ailments that become more common as we age, I am sure that a number of things would come to mind. Amongst other common problems, Hearing loss and Dementia/Alzheimer’s disease would probably be on that list. But did you know that research has actually found a link between Hearing loss and Dementia? In recent years, several different studies have investigated this relationship, and the results might come as a shock to some. Most people will think that hearing loss and dementia are just normal parts of aging, but recent studies suggest that hearing plays a vital role in brain health.

Results of various different studies, performed by different universities all over the world have found that the odds of developing Dementia are much higher in adults who have hearing loss. Results also suggest that the more significant the hearing loss, the higher the likelihood of Dementia. One study performed at Johns Hopkins University estimated that people with mild hearing loss are twice as likely to develop Dementia. Moderate and severe hearing loss increase the likelihood of developing Dementia even further (3 – 5 times more likely respectively).  The rate of cognitive decline also seems to increase when hearing loss is present, as the research shows. Studies have shown that adults with hearing loss had cognitive decline 30-40% faster than that of adults with normal hearing.

Dr Frank Lin from Johns Hopkins, who has led many of the studies in this field, describes the relationship between hearing loss and dementia as a combination of the following three factors:

  • One of the consequences of hearing loss is social isolation – when you have a hearing loss it is difficult to hear and converse in social situations. The natural consequence is often to avoid going out and engaging in social activities, resulting in isolation and a feeling of loneliness. Loneliness and isolation in turn poses a higher risk for the development of Dementia/Alzheimer’s Disease.
  • We hear with our ears, but listen with our brains. When our ears hear sounds, our brains match what we have heard to information stored in our brains and interpret what we have heard. When a hearing loss is present, our brains have to work much harder to decode and make sense of what we have heard. This increases the cognitive effort required to listen, meaning that there are less cognitive resources available for our brain to perform other tasks (e.g. short-term memory), resulting in the brain being left more vulnerable to cognitive decline.
  • When a hearing loss is present, the auditory nerves send fewer signals to the brain – resulting in areas of the brain being left under stimulated. This can also contribute to cognitive decline.

In saying this, research is not able to establish Hearing Loss as a cause of Dementia/Alzheimer’s Disease (or vice versa), rather that there is a very strong correlation between the two.

The good news is, that treating a hearing loss as early as possible with the use of hearing aids and or a Cochlear Implant if applicable, can help to lessen the impact of hearing loss on the brain. We love how Dr Jana Besser, who has conducted a lot of research in the field of the impact of hearing loss on the brain, puts it: ‘Hearing aids should actually be seen as neurological “brain” devices!’ Appropriately fit hearing aids can help an individual hear better in social situations, meaning that they don’t have to stay at home just because they can’t hear. Hearing aids can ensure that social engagements and meaningful conversations can still take place, regardless of the fact that they have a hearing loss. Hearing aids also make speech clearer – meaning that our brains don’t have to work as hard to make sense of what we are hearing. This also means that the desired signals are sent to the brain, leaving the auditory areas of the brain well stimulated.

In most cases hearing loss in the adult population develops gradually over time. Our brain’s ability to initially compensate makes it difficult to identify in the early stages of hearing loss (or result in adults postponing going for a hearing test because ‘it’s not that bad yet…). Bearing the above in mind however, it is important to identify a hearing loss and intervene as soon as possible. Taking the time to have a hearing test, monitoring hearing loss and taking the necessary action when needed can have a significant impact on your brain health and quality of life! The longer a hearing loss has been present, the bigger the impact on the brain, and the more difficult it becomes for the brain to learn to listen again. If you haven’t had your hearing tested, or if it’s been a while since your last hearing test, it might be time for you to have a check-up…before it’s too late!

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