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Hearing loss may push decline in memory, thinking
January 22nd, 2013
11:03 AM ET

Hearing loss may push decline in memory, thinking

Older Americans who have hearing loss have an accelerated decline in thinking and memory abilities, compared to those with normal hearing, according to a study published in JAMA Archives of Internal Medicine.

Those with hearing loss experience a 30% to 40% greater decline in thinking abilities compared to their counterparts without hearing loss, according to the findings published Monday.

Hearing loss is common among old older adults, affecting about two-thirds of adults 70 and older, and about one-third of adults younger than 60, according to lead study author Dr. Frank R. Lin of Johns Hopkins University.  A large number of people with hearing loss are untreated, Lin explained, because they associate hearing loss with the stigma of getting older.

About two years ago Lin and his associates published a paper showing that hearing loss was associated with greater risk for developing dementia. “Fortunately most of us will never develop dementia, but most of us will experience some kind of cognitive decline over time,” explained Lin.

Rather than looking at hearing loss and dementia, the researchers studied people with normal cognitive function to determine whether people with hearing loss had different rates of memory and thinking decline compared to people with normal hearing. Dementia rates are projected to rise as the world's population ages, the study noted; identifying factors that may contribute to cognitive decline and dementia in older adults may lead to ways to slow and treat brain decline.

The researchers studied about 2,000 older adults enrolled in a long-term study which began in 1997. All subjects included in the study had no dementia or cognitive impairment.  Each subject went through an audiometric assessment performed in a sound-treated booth, which Lin described as “the gold standard” for hearing testing. Their memory, thinking abilities and decision-making were also tested. Both tests were repeated at three, five and six years, and researchers looked at average decline in memory and thinking abilities, comparing people with normal hearing to those with reduced hearing.

“We found that people with hearing loss had a faster rate of mental decline compared to people with normal hearing. ... And the greater the rate of hearing loss, the faster the decline of memory and thinking. It was dose dependent,” said Lin. People with hearing loss took 7.7 years to have a five-point drop in their thinking skills, compared to 10.9 years for people with normal hearing.

Why does this happen? Lin said there’s no definite explanation, noting that various explanations may apply. When people suffer from hearing loss, it’s not that they can’t hear. It’s that the cochlea, the part of the inner ear that converts a complex sound to a precise signal that goes to the brain for decoding, isn’t doing a good job converting, so people hear a garbled signal. Lin described it like a bad cell phone connection.

One theory is that "if the brain is dedicating extra resources to try and hear what’s going on, it's probably taking away from other brain resources like thinking and memory, “ explained Lin.

A second explanation, using the cell phone example, is that people experiencing lousy reception end up tuning out, because it’s so labor intensive to try to hear the call. This explanation plays into the idea of social isolation, which has been shown to have negative health effects including increased illness, death rates, and increased cognitive decline and dementia.

A third possible explanation is that some mechanism in the brain is affecting both hearing and brain function. Lin said it's likely that the hearing loss and brain decline are explained by all three factors. He also acknowledged that while his study tried to adjust for other factors affecting hearing and cognitive abilities, they did not account for factors including something in the inflammatory process or the age of mitochondria, the energy factories of cells.

Lin thinks the big public health question is whether treating hearing loss will have an impact on brain function and memory decline.


soundoff (22 Responses)
  1. dave557

    Interesting but there is still not enough evidence that hearing loss increases the risk of dementia. it could also be other factors such as air quality http://malalzheimer.blogspot.com/2013/01/dementia-help-can-be-provide-when-you.html

    January 22, 2013 at 12:07 | Report abuse | Reply
  2. Hahahahahahahah

    What? Hahahahahahahahah

    January 22, 2013 at 16:19 | Report abuse | Reply
  3. Gregory Faith

    My memory is fine just like my........my.....................my................never mind.

    January 22, 2013 at 17:28 | Report abuse | Reply
  4. diana

    i am deaf, and i have no dementia. perhaps, the increase of dementia because of little or no social communications. irregardless if the person with hearing loss or not, dementia is not related to deafness. most people don't spend times with the elderly, where communication is so vastly needs as well as social, and in the nursing or living homes. thats my opinions.

    January 23, 2013 at 00:34 | Report abuse | Reply
  5. Lisa

    That's ridiculous; I am deaf, I am from a family of five generations of deaf people (more than 30 deaf people in total), and I can promise that the only deaf person in my family didn't have good memory at the end of his life and that's because he had a stroke. My family has been immensed in the deaf culture for more than 100 years, and I can promise you that anybody could have dementia regardless of his or her hearing status.

    Absolutely ridiculous study.

    January 23, 2013 at 09:26 | Report abuse | Reply
    • Lisa B.

      I completely agree. I'm deaf too. Been deaf since I was a toddler. This article leaves too much out. I strongly believe that older adults who start losing their hearing should start learning sign language and use closed captioning and learn about Video Relay services. In other words, learn how real deaf people get along in the world. We do pretty darn well being deaf.

      ~Lisa B.

      January 28, 2013 at 22:00 | Report abuse |
  6. Jules

    the study did not metion anything about deaf people, it was based off individuals who had normal hearing and then had hearing loss. If you are deaf you are not straining to hear things, you just don't hear them, and you communicate normally by other means. If you are used to communicating through hearing and then you cannot communicate that way (and most normal hearing people do not know sign language or have alternate ways of communicating unfortunately – as the deaf community does) it is reasonable to me that would cause confusion and cause you to just stop trying to communicate. Therefore, if you begin to withdraw from normal human interaction I can see how that would cause your brain to decline, use it or lose it. I have read other studies that point to the fact that if you don't use your brain in many different ways and stop learning new things, your brain starts to decline.

    January 23, 2013 at 14:39 | Report abuse | Reply
    • Lisa B.

      That's one of the problems of this article: they didn't bring up the issue of deaf people and how their brain function compares to newly deaf older adults. This article lacks scientific data and contains too many leak holes inviting an abundance of assumptions on its readers. I feel that CNN should have elaborated further on the communication factor, such as how can newly deaf older adults evolve their communication skills? Personally I believe that older adults don't need to resign to a lifelong sentence of isolation. There are options, the most obvious being that they can get hearing aids (including Cohlear Implants). But they can also learn sign language and adopt a Deaf culture lifestyle. Eventually, the confusion will cease. The human body is well capable of evolving in the face of drastic changes.

      January 29, 2013 at 16:11 | Report abuse |
  7. DLO

    One tragically overlooked opportunity for the elderly also pertains to the ear......the inner ear.....as the balance portions age we will naturally lose some balance. The brain will also shift it's emphasis to the task of balancing the body also leaving one with impaired thinking. A BPPV (a form of vertigo) patient will have impaired thinking, loss of short term memory etc..... Some vestibular therapy for the elderly may be an opportunity for improving thinking in some cases.

    January 23, 2013 at 16:26 | Report abuse | Reply
  8. empresstrudy

    So what? Insurance plans don't pay for hearing aids. At least not any of the usable ones.

    January 25, 2013 at 11:49 | Report abuse | Reply
  9. DeafEmily

    How so absurd. Seriously, whoever did this research obviously is soliciting for BIG cochlear implant industries. YOU know that research is 99% biased. Don't believe any sh!t you hear. I am deaf and born deaf and have 3 college degrees, traveled around the globe, and I still have my "MARBLES."

    January 25, 2013 at 13:23 | Report abuse | Reply
  10. 911pam

    Several years ago I awoke to muffled hearing. Just Thought it might be a sinus and ear problem, but within 24 hrs I had lost 100% hearing in my right ear. As a 911 Operator and of course needing hearing to do my job I went to a walk in clinic. The Dr there told me it was allergies, irrigated my ear, take some Mucinex, and sent me home. 48 hrs later I was still no better and feeling slightly confused and listing to one side when walking. I took myself to an Ear Nose & Throat Dr and was told I needed extensive testing as an episode of sudden hearing loss can be a life threatening issue if the cause is a stroke. I was tested for STD's, autoimmune disorders, stroke, and when all was ruled out the diagnosis was Sensioneural Sudden Hearing Loss. Immediately my Dr presribed oral steriods and then steroidal shots directly into the ear drum. I did recover most of my hearing.

    WHAT IS IMPORTANT FOR PEOPLE TO KNOW IS THAT YOU HAVE A 72 HR WINDOW TO GET STEROIDAL TREATMENT OR MORE THAN LIKELY YOUR HEARING LOSS WILL BE PERMANENT AND UNRESOLVED.

    The feelings of confusion are still with me but not as bad initially some 5 yrs later. My dr explained that the brain is always searching for it's "speaker" for dual sound intake and that is part of the reason for continued confusion.

    Mine is very slight and manifests more in a slowing of my thinking in a minor way. What is interesting is that I still work taking 911 calls and I have had many quality assurance tests and I test either perfect in my call taking or near perfect.

    I do need increased volume and a double headset but I am very good at what I do. Hearing is just one part of the equation, and the other is Active Listening which uses a different part of the brain.

    However I do believe when the hearing loss occurred there was also a neurological event occurring as well. I certainly will be self monitoring not only for my job but for my future as I approach my 60's.

    January 26, 2013 at 08:55 | Report abuse | Reply
  11. Judy Lynn Pearce

    As a speech pathologist I found this article especially interesting. Presbycusis is the concept of hearing loss associated with aging. During graduate school at Chapel Hill we obviously studied a lot about cognitive changes associated with Alzheimer's and dementia related conditions. Similarly we studies hearing loss and the impact of being born deaf versus acquiring a hearing impairment as an older adult. We never discussed any links between cognitive decline and hearing impairment. Given the amount of new research in the area of neuro-science I personally we continue to look for more evidence before forming any strong opinions. As with any new science there is always much speculation. Looking at the flood of information on the benefits of brain games in the market and the hypothesis that they will prevent cognitive decline, I similarly have reserved judgement on these issues. It would be interesting for one of those websites like Lumosity to do a study on this. I personally have a hearing impaired father who is 80 and he is 100% sharp – he does read, exercises, plays brain games (there are even free sites like http://www.BrainSpade.com or AARP has a good one) and he eats right. Everything in moderation is what he says and as a clinician I have to admit I agree with him. Balance is most important. Ah but I digress...

    January 27, 2013 at 12:06 | Report abuse | Reply
  12. Cruzer

    I am have been losing some of my hearing but I have not lost my thinking/analyzing ability which tells me that the sale of hearing aids (the price of hearing aids-over$2K) is a rip-off of the greatest magnitude. The same thinking/analyzing ability also tells me that the sale of prescription glasses/eye wear (the price is over $150 if one can find such low price) is another medical provider rip-off especially when one compares the$1.00 cost of reading glasses frames and lenses at the $0.99 cent stores. So whose thinking ability is warped? That of the ones who have lost some of their hearing ability or that of the rip-offers whose greed can never be satisfied?

    January 28, 2013 at 12:57 | Report abuse | Reply
  13. YayaMama

    As a deaf person, this article and "study" struck me as utterly ridiculous. If this study had any validity whatsoever, they'd be testing deaf children and comparing them to their peers and/or doing the same with 20-somethings. This article presented little to no facts other than 7 yrs. vs. 10yrs to a "5 point drop in their thinking skills," whatever "thinking skills" means.

    Filling column inches with this sort of nonsense is shameful.

    January 29, 2013 at 12:43 | Report abuse | Reply
  14. Irma

    This may be interesting to you and all our family – if we get a hearing aid, we may actually give our brains less stress so we don't give into dementia/alzheimers too young!

    January 29, 2013 at 13:56 | Report abuse | Reply
  15. Mary

    I can't get a hearing aid for my bad ear because I don't carry credit cards and my work insurance doesn't cover for it. It takes a long time to save up $2000-$2500 when you have kids to care for....

    January 30, 2013 at 15:35 | Report abuse | Reply
  16. Fran

    I wonder if people with hearing loss who wear hearing aids were included in this study and if so did this have an impact in the results?

    February 4, 2013 at 18:31 | Report abuse | Reply
  17. Thomas Fairclough

    I found this aritcle whilst researching industrial deafnesshttp://www.asons.co.uk/hearingloss.. Previously I had no idea about the potential connection between memorly lossand hearing loss.

    Tom Fairclough
    http://www.asons.co.uk

    June 17, 2013 at 11:16 | Report abuse | Reply
  18. Alison N.

    I think everyone is missing the point. This study was directed at adults with late onset hearing loss. A deaf individual has a whole other set of considerations and is not included in this study. I work with hearing impaired people every day and the one thing I would assure you, if you don't use it you lose is. You Lisa as a deaf individual – have other modes of communicating and therefore are not "losing anything"... However, as for your statement that you are doing pretty darn well being deaf – how many people do you know that are deaf and not on social assistance?

    June 21, 2013 at 11:26 | Report abuse | Reply
  19. Pamala Jukes

    Hearing loss exists when there is diminished sensitivity to the sounds normally heard. The terms hearing impairment or hard of hearing are usually reserved for people who have relative insensitivity to sound in the speech frequencies. The severity of a hearing loss is categorized according to the increase in volume above the usual level necessary before the listener can detect it..^`,

    Newest content article on our internet site http://www.healthmedicine.cobu

    June 22, 2013 at 10:02 | Report abuse | Reply
  20. Dee

    This article fails to address what type of testing was used,how the testing it self has been used with hearing disabled. This can be dangerous and lead to medical discrimination against the disabled whose communication skills are altered . the hearing impaired are difficult to assess with test taking Apparently, this article implies that they used the same tests and compared them. However, different tests are needed as hearing impairment alters test taking skills and assessments. Thia was not discussed. .This type of article ,without more information,negativly educates the public concerning the hearing impaired! Now they will fight being labelled as having dementia when they do not. In the past ,society labelled the deaf as idiots and seems prepared to do so again!

    July 4, 2014 at 09:30 | Report abuse | Reply

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