Hearing Loss and Dementia

Fear or Fact?

As professionals, we have seen it for many years – the connection of our client base and the high percentage with memory loss. Research had been minimal to show the link between hearing loss and memory issues, but a recent published article from Dr. Frank Lin and his team at John Hopkins Department of Ololaryngology over an 11 year period found some startling results.  Here is an abstract from that publication:

Context—Earlier studies have suggested that hearing loss, which is prevalent in more than 30% of adults >60 years, may be a risk factor for dementia, but this hypothesis has never been investigated prospectively.

Objective—To determine if hearing loss is associated with incident all-cause dementia and Alzheimer’s disease (AD). Design, Setting, and Participants—Prospective study of 639 participants (age 36 – 90 y) of the Baltimore longitudinal Study of Aging who had audiometric testing and who were dementia-free in 1990-1994. Hearing loss was defined by a pure-tone average of hearing thresholds at 0.5, 1, 2, and 4 kHz in the better-hearing ear (normal <25 dB [n = 455], mild loss 25-40 dB [n = 125], moderate loss 41-70 dB [n = 53], severe loss >70 dB [n = 6]). Diagnosis of incident dementia was made by consensus diagnostic conference. Cox proportional hazard models were used to model time to incident dementia according to severity of hearing loss and were adjusted for age, sex, race, education, diabetes, smoking, and hypertension.

Main Outcome Measure—Incidence of all-cause dementia and AD until May 31, 2008.

graph from study in 2008 about the risk of demential with hearing loss showing a correlation between the two conditions.

Results—During a median follow-up of 11.9 years, 58 cases of incident all-cause dementia were diagnosed of which 37 cases were AD. The risk of incident all-cause dementia increased loglinearly with the severity of baseline hearing loss (1.27 per 10 db loss, 95% CI: 1.06 – 1.50). Compared to normal hearing, the hazard ratio for incident all-cause dementia was 1.89 for mild hearing loss (95% CI: 1.00 – 3.58), 3.00 for moderate hearing loss (95% CI: 1.43 – 6.30), and 4.94 for severe hearing loss (95% CI: 1.09 – 22.4). The risk of incident AD also increased with baseline hearing loss but with a wider confidence interval (1.20 per 10 dB of hearing loss, 95% CI: 0.94 –1.53).

Conclusions—Hearing loss is independently associated with incident all-cause dementia. Whether hearing loss is a marker for early stage dementia or is actually a modifiable risk factor for dementia deserves further study.

As Dr. Lin states, there is still more information to gather but the end result is a clear and remarkable link between hearing loss and dementia. I often counsel my clients with a common sense approach and I explain it this way:

“I challenge you to find a single memory that you have that is NOT tied to one of your five senses.  It’s impossible.  everything we experience is directly related to sensory input, whether it be sight, smell, taste, touch or hearing.  How many times has it happened that you smell fresh baking and you are brought back to your childhood?  All these inputs are like the fingers on your hand feeding into the palm – your memory system – and our hand work much better with all the fingers in place and working effectively.”

To learn more about what can be done to reduce your risk or to learn more about these findings, contact us for a consultation today.

reference: http://www.fchearing.ca/news/?p=58

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