Hearing Loss and Dementia

Contributed by: Dennis Fortier, President, Medical Care Corporation
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Is there a relationship between hearing loss and dementia?  If so, what is it?  There is a lot of press right now on this topic; the interest is driven by a publication in this month's issue of Archives of Neurology.

In the study behind the publication, researchers followed 639 men and women between the ages of 36 and 90, none of whom were demented at the start of the investigation.  By monitoring the subjects' cognition as well as their hearing, researchers discerned a positive correlation between hearing loss and dementia.

Several theories were put forth to explain this result. However, I think the most obvious explanation of the potential relationship was not discussed in the paper.

Among the suggested explanations was the notion that hearing loss is merely a sign that someone is not aging very successfully from a biological perspective.  Therefore, it would stand to reason that the health of that person's brain is also declining with age.  That is possibly true but not very useful in terms of explanatory power.

A second thought was that hearing loss might be the result of nerve damage affecting the neurological processing of auditory signals.  That seems plausible but also very speculative.

Finally, some suggested that hearing loss can lead to social withdrawal, and that low levels of social engagement have been shown to increase risk for Alzheimer's disease.  That's logical.  But those relationships are quite weak, and the evidence supporting them is scant.

I think there is a more obvious aspect of this study that must be considered.   The researchers looked primarily at the relationship between hearing loss and dementia.  As we know, dementia is not a disease but a classification of cognitive function.  Specifically, dementia is defined as a state of cognitive impairment severe enough to interfere with daily activities.

The obvious confound here is that hearing loss by itself, even with a healthy brain, can also greatly interfere with daily activities.  After all, it is hard to remember things that you never heard correctly to begin with.  It is also difficult to focus on a complex task when your brain is fully engaged in trying to decipher and make sense of the garbled sounds you perceive with faulty hearing.  To an unknowing observer, a research subject with hearing loss, who focused on the task of hearing, might look like he has cognitive problems when, he is actually just dividing his attention in a non-obvious way.

Perhaps some observed difficulties among the research subjects were caused by hearing loss and then misclassified by the researchers as cognitive problems.  This would lead to the false appearance of a relationship between hearing loss and dementia in cases where the researchers were really only observing hearing loss.

Obviously, my thoughts on this matter are no more well supported than the other explanations I noted above.  But when a story explodes in the press as this one has, I think it is useful to consider it carefully, and to draw conclusions only after a prudent and diligent review of the facts.

13 comments :

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  3. Good covered point, lots of people simply put something weired theories in front of public.
    But it doesn’t work i think because know one sure how it will going to happen
    It looks like just coping ideas which someone has already written. I found even on
    popular blogs guest bloggers bring same theories which I already know. I observed they
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  4. Seniors with hearing loss are significantly more likely to develop dementia over time than those who retain their hearing. The reason for the link between the two conditions is unknown, the investigators suggest that a common pathology may underlie both or that the strain of decoding sounds over the years may overwhelm the brains of people with hearing loss, leaving them more vulnerable to dementia. They also speculate that hearing loss could lead to dementia by making individuals more socially isolated, a known risk factor for dementia and other cognitive disorders.

    Audiologist

    ReplyDelete
  5. In my late 40's I started to loose my hearing. 10 years later I have severe sensoneural hearing loss and wear hearing Aids. I can tell you from experience that hearing loss sucks. I am withdrawn in a world of my own, not because I want to be there but because I find it hard to relate to other's or they don't have the patience to relate to me. I do have temporary moments of forgetting. More so during stress periods. The hearing Aids don't always help as much as I would like. I'm worried. My mom has been diagnosed with dementia, I don't want to end up like her.

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  6. It looks like just coping ideas which someone has already written. I found even on
    popular blogs guest bloggers bring same theories which I already know.

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  7. Interesting ideas. I think there is more research that needs to be done on this subject. For those of you who are doing research about hearing loss, also check out Healthyhearing.com.

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  8. Fantastic site, thanks for the detailed information
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  9. Hi guys,
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  10. This is pure knowledge about the neurology especially for brain in which all other things are discussed.

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  12. More so during stress periods. The hearing Aids don't always help as much as I would like. I'm worried. My mom has been diagnosed with dementia, I don't want to end up like her.

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