Hearing Loss & Dementia

Today, now more than ever, an emphasis is being placed on health and wellness. How do we stay active? How do we reduce our risk of “aging diseases”? What do we need to do to stay healthy and what all does that include?

The Centers for Disease Control expects that the number of people living with cognitive impairment (a loss of cognition that can include: memory loss, frequently asking the same question, repeating the same story, not recognizing familiar surroundings or people, and trouble exercising good judgment) will ”jump dramatically” with the Baby Boomer generation passing the age of 6512. The CDC estimates that Americans aged 65 years or older who may currently have Alzheimer’s will increase by more than double the current number (5.1 million to 13.2 million by 205012).

Cognitive impairments such as Alzheimer’s and dementia are the 3rd most expensive diseases to treat in the United States. Loss of our mental capacity is twice as feared as our loss of physical capacity12. In addition Alzheimer’s disease and related dementia (types of cognitive impairment) are the 3rd most expensive disease to treat in the United States12.

In the United States it is estimated that hearing loss affects 12.7% of the population, nearly 30 million adults1. The chances of having hearing loss that affects your physical and brain health (cognition) are 1 in 10. Of those with hearing loss, even a mild hearing loss is significant enough to affect your cognition and lead to cognitive declines. This connection between cognition and hearing health should make treating any hearing loss a priority.

Even a mild hearing loss, left untreated, can negatively impact cognition.5  Frank R. Lin, MD and colleagues have been studying the effects of hearing loss on brain health. Their studies have linked our hearing and the health of our brains as we age3, showing “…individuals having hearing loss demonstrating a 30% to 40% accelerated rate of cognitive decline and a 24% increased risk for incident cognitive impairment during a 6 year period compared to individuals with normal hearing”.4  A 25 dB hearing loss = 6.8 years age difference in cognitive performance. They also found, “The reduction in cognitive performance associated with a 25 dB hearing loss was equivalent to the reduction associated with an age difference of 6.8 years.”5 Hearing loss ages your brain and increases your likelihood of developing a cognitive impairment.

Chien, Wade C.; Lin, Frank R. (2012) estimated that 22.9 million adults with hearing loss do not use hearing aids.2 Dr. Lin’s 2011 study found, “The risk of incident dementia became evident for hearing loss of greater than 25 dB and thereafter increased log linearly with a more severe loss.”3 Meaning the more hearing loss you have the greater your risk of dementia.

How do we reduce our risk of hearing loss related cognitive decline?  We reduce our risk by utilizing appropriate and adequate amplification (hearing aids) which help to mitigate the effects of hearing loss by providing the brain full auditory/aural stimulation. The key to hearing better with hearing aids is matching the hearing loss needs of your auditory system with how your brain hears and processes sound.  A common misconception is that we “hear” with our ears, but we actually hear with our brains. Our ears are simply a sound detection system, but it is our remarkable brains that take in that information and make something of it. It is our brains and our ability to think [cognition] which allows us to hear and attend to, or ignore the dog barking or the refrigerator running. Most importantly our cognition enables us to understand speech.

Having good cognition will enable us to better utilize the sound hearing aids provide us. By not hearing all the sounds across the spectrum we deprive our brains causing Auditory Deprivation. When we deprive our brains of sound it cannot “strength train” and will weaken over time.

In addition if we do not understand what is said, the brain will not process it as a memory.  Why would our brains remember something that is non-sense? By not utilizing the memory portion of our brains as much as possible it can lead to aging diseases such as Dementia and/or Alzheimer’s. Hearing all the speech sounds at appropriate volumes throughout all the ranges of speech we provide the brain with more information which results in an increased chance of understanding clearly, which leads to increased use of the memory systems of the brain.

Question:

 How do we reduce our risk of having “aging diseases”?

Answer:

With early intervention using appropriate amplification.

References:

1. Frank R. Lin, MD, PhD; E. Jeffrey Metter, MD; Richard J. O’Brien, MD, PhD; Susan M. Resnick, PhD; Alan B. Zonderman, PhD; Luigi Ferrucci, MD, PhD . Hearing Loss and Dementia Linked in Study (2011). Arch Neurol. 2011;68(2):214-220. doi:10.1001/archneurol.2010.362.

2. Hardy, C., et.al, (2016). Hearing and Dementia. Journal of Neurology. doi:10.007/s00415-016-8208-y.

3. Lin, Frank R.; et al. (2011, Feb). Hearing Loss and Incident Dementia. Arch Neurol. 2011 Feb; 68(2): 214-220.

4. Lin, Frank R.; et al. (2013). Hearing Loss and Cognitive Decline in Older Adults. JAMA Internal Medicine 173(4), 293-299.

5. Lin, Frank R., et al. (2011). Hearing Loss and Cognitive in the Baltimore Longitudinal Study of Aging. Neuropsycholocy 26(6) 763-770.

6. Amieva H, Ouvrard C, Giulioli C, Meillon C, Rullier L, Dartigues JF. (2015). Self-Reported Hearing Loss, Hearing Aids, and Cognitive Decline in Elderly Adults: a 25-Year Study. J Am Geriatr Soc 63(10);2099-104.

12. Cognitive Impairment: A Call for Action, Now! (2011). Available at: www.cdc.gov/aging/healthybrain/index.htm.

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