Collier Edition

Does Hearing Loss Cause Dementia?

By Dr. David B. Rawlings, PhD

Does Hearing Loss Cause DementiaDo you know anyone who has been suffering from mild to moderate to severe hearing loss? I know I do. Personally, I’ve had my own problems hearing friends talking; particularly, when we go out with several couples and we’re sitting at a large table in a busy restaurant.  I really have to concentrate on what one person is saying to the detriment of what else might be going on around me, and then I might miss a side conversation. It really makes me think twice about where we go out and with how many friends.

Well, if putting a kibosh on my social life wasn’t bad enough, hearing loss has now been reported to be associated with accelerated cognitive decline and cognitive impairment in a study of older adults. Seniors who suffer hearing loss are reportedly at a higher risk for developing dementia according to research by Frank Lin, M.D., an otolaryngologist and epidemiologist, at John Hopkins School of Medicine in Baltimore, MD.

Compared to persons with normal hearing, those individuals with a mild, moderate, and severe hearing loss, respectively, had a 2-, 3-, and 5- fold increased risk for developing dementia over the course of the study. The study, published in the 2011 Archives of Neurology, Dr Lin and his colleagues looked at 639 subjects ranging in age from 36 to 90 (with the majority of subjects between 60 and 80). None of these subjects had cognitive impairment at the beginning of the study, while some had hearing loss. The conclusion: the worse the hearing loss, the greater the risk for developing dementia. This was particularly true when other variables such as age, diabetes, and hypertension, etc., were ruled out.

More recently, Dr Lin reported new findings in JAMA (Internal Medicine) from research employing a total of 1,162 subjects.  Those individuals with baseline hearing loss had annual rates of decline in test scores (which measured global and executive function) that were 41% and 32% greater, respectively, than those among individuals with normal hearing. Compared to those individuals with normal hearing, individuals with hearing loss at baseline had a 24% increased risk for incident cognitive impairments. The conclusion: the worse the hearing loss, the worse the rate of cognitive decline.

Dr. Richard Gurgel at the University of Utah also reported a study which included 4,463 men and women, aged 65 years or older, who did not have dementia at baseline. 700 of those had hearing loss. In the hearing loss group, 16.3% developed dementia over the course of the study, compared with 12.1 % of those without hearing loss. Mean time to dementia was 10.3 years in the hearing loss group vs.11.9 years for patients with normal hearing. After controlling for gender, and education, etc., the investigators found that hearing loss was an independent predictor of the development of dementia.
What’s causing this?
The answer is not totally clear….yet. Keep in mind that correlation does NOT mean causation!!

One explanation is a common pathological process called reverse causation; a phenomenon involving degenerative pathology involving both genetic and environmental factors put forth by Dr. John Gallacher at Cardiff University.

After analyzing their MRI’s over the last few years, Dr. Lin will be reporting in an upcoming issue of NeuroImage that those participants whose hearing was already impaired at the start of his sub-study had accelerated rates of brain atrophy compared with those with normal hearing. Overall, the scientists report, those with impaired hearing lost more than an additional cubic centimeter of brain tissue each year compared to those with normal hearing. Those with impaired hearing also had significantly more shrinkage in particular regions of the brain, including the superior, middle and inferior temporal gyri; brain structures responsible for processing sound and speech.

Dr. David Friedland from the Medical College of Wisconsin and other researchers including the Framingham Heart Study suggested an association between hearing loss and cardiovascular disease. Since the inner ear tends to be so sensitive to blood flow changes, any vascular abnormalities could be noted earlier in the ear than in other parts of the body.

Another theory proposed between hearing loss and cognitive impairment is, “cognitive load” This is what I experience in a noisy restaurant when I’m with a lot of friends!! I might be hearing, but not actually listening. When I say I’m conversing….I’m actually pretending. I may hear some of the words, but not all of the words. What I end up doing is putting a lot of effort into hearing and using up a lot of brain power that I should be using for other things. This “cognitive load” becomes more of an overload at times. In essence, my brain is so pre-occupied with translating sounds into words that it doesn’t seem to have much processing power left to search through my data bank to give a fast or appropriate response to the topic at hand.

What happens as hearing declines?
I hear this a lot from my clients and their spouses.  As hearing loss gradually progresses, the compensatory strategies used to improve communications such as lip-reading, become less effective. People become resistant to wearing hearing aides or they are too expensive to purchase. When these strategies become less effective it can lead to increased social withdrawal. People with hearing loss, often avoid social gatherings and withdraw as a result of the frustration and/or embarrassment that stems from their inability to follow conversations. Social withdrawal and limited interactions with peers and family members can lead to depression which, in turn, can possibly speed up the progression of dementia.

What can you do about it? Get your hearing tested. Have your kids, and family screened. Get it corrected.  Unfortunately, hearing aides aren’t always the answer.  Look into new digital technology such as “hearing loops” at hearingloop.org.

Get out and socialize….even if it’s with one or two people or a small group of people. Take up some hobbies. Exercise…..30-40 minutes a day; 3 days a week. Eat a Mediterean Diet; a colorful palette of fruits and vegetables. Drop your blood cholesterol. Reduce your risk for stroke and high blood pressure by not smoking, decreasing your salt intake, and moderate your alcohol intake. Sleep well. Meditate and slow up your life.

If you feel you or your loved one are having cognitive difficulties or memory issues, our office can test you and/or yours to see if you or they are experiencing benign, age-related problems, or neurological-impairments that require greater attention. Remember, hearing loss and depression frequently mimic memory symptoms but are not the same and do require a specialist to differentiate one from another.

Dr. David B. Rawlings, PhD
720 Goodlette Road N. | Suite 201 | Naples FL 34102
239-430-2303 | www.drrawlings.com

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