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The link between hearing loss and dementia is better understood thanks to new research from the US and the UK and the results are really quite striking.
According to the Sydney Memory and Ageing Study, hearing loss is the second-most common health condition, affecting 74% of people aged over 70.
That is an alarming statistic when you extrapolate research from Johns Hopkins University which tracked 639 adults for nearly 12 years and found that mild hearing loss doubled dementia risk. Moderate loss tripled risk, and people with a severe hearing impairment were five times more likely to develop dementia.
The link between hearing loss and dementia was first made more than 30 years ago but a concerted focus by researchers has only taken place in the past 15 years.
In 2017 The Lancet Journal identified nine potential risk factors for dimension and the greatest of these risks was hearing loss.
Common symptoms of both dementia and hearing loss overlap readily, including confusion during conversation, changes in methods of communicating, difficulty completing everyday tasks, and feelings of fatigue or stress. As a result, hearing loss can be misdiagnosed as dementia or make the symptoms of dementia appear worse.
The good news is scientists have found a positive association with people who used hearing aid and better episodic memory scores.
Now, the UK’s Newcastle University has a new theory to explain how a disorder of the ear can lead to Alzheimer's disease. The research has shown the part of the brain, typically associated with long-term memory for places and events, is also involved in short-term storage and manipulation of auditory information.
This matches other research which found shrinkage of brain tissue is fast-tracked for those with hearing loss, with accelerated rates of brain atrophy compared to those with normal hearing. Those with hearing loss were found to have lost more than an additional cubic centimetre of brain tissue each year compared with those without impaired hearing.
That loss was most prevalent in regions of the brain responsible for processing sound and speech, including the superior, middle, and inferior temporal gyri.