The better to hear you, the better to remember

A leading Johns Hopkins University otology expert who was a key speaker at a conference in Israel believes there is a link between untreated hearing loss and dementia.

By
October 17, 2016 23:55
FRANK LIN

FRANK LIN. (photo credit: Courtesy)

If you’re embarrassed to wear a hearing aid because you think it casts you as “old,” think again.

A leading expert in hearing loss from Johns Hopkins University suggests that there is a link between untreated hearing problems and dementias such as Alzheimer’s disease.

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Johns Hopkins University’s Prof.

Frank Lin, recognized as the leading expert on this epidemiological connection, is not sure yet whether treating hearing loss will lower one’s risk of Alzheimer’s disease, but he and his Baltimore colleagues are about to conduct an intensive, five-year study of the subject.

The otology and head-and-neck surgeon and geriatric medicine specialist spent a couple of days in Israel recently to speak at a Sheba Medical Center and Tel Aviv University conference on hearing rehabilitation in older adults at the invitation of the Med-El company, which makes cochlear implants. It was his second visit to Israel, Lin said in an interview with The Jerusalem Post. “I was in Eilat three years ago.”

The son of two physicians and public health researchers and the brother of a doctor and an economist, Lin was born at Johns Hopkins University Medical Center. His parents emigrated from Taiwan and moved to Maryland shortly before his birth in the 1970s.

“I have always been drawn by big public health problems. I have found that hearing, especially in the elderly, frequently gets ignored.”

His research is primarily funded by a US National Institutes of Health (NIH) Career Development Award and is focused on studying the interface between hearing loss and aging. Lin says he spends 80% of his time on research and the rest on treating patients.

“If I would do only one or the other, I would get bored,” he confessed. “But from what I learn from the patients I treat, I apply to my research.”

In particular, Lin has established multiple collaborations with gerontologists, cognitive scientists, epidemiologists and auditory scientists that form the basis for his current research program studying the impact of hearing loss on the cognitive and physical functioning of older adults and the potential role of aural rehabilitative strategies in mitigating these effects.

At Brown University in Rhode Island, Lin met his wife, who is a veterinarian. “We have a cat and a 14-year-old dog, who has completely lost his hearing,” he noted with irony. “I can’t help him, as there are no hearing aids for dogs, but deaf cats were a model for cochlear implants.”

So many who could benefit from hearing aids don’t use one, Lin said. The rate varies from country to country, he added. In the UK, which has National Health Insurance, the figure is only a bit better and in Scandinavia somewhat better. The official Israeli rate is not known.

Hearing loss can be mild or severe, present at birth or begin later in life, occur gradually or suddenly, resulting from excessive noise, health conditions or aging. An estimated 30 million Americans have hearing loss. Around the world, hearing loss has been identified as the fifth leading cause of years lived with disability.

As the population of older adults increases, hearing loss will become an area of greater concern. Hearing is a vital human sense important to communication and health and a significant component of quality of life, but for a variety of reasons, many people with hearing loss go without seeking or receiving help to hear.

Between 67% to 86% of US adults aged 50 and older who may benefit from hearing aids do not use them. Thus many hearing assistive technologies as well as auditory rehabilitation services are not fully utilized.

Long seen as an issue for individuals (and to some extent their families and friends), there is a growing recognition that hearing loss is a significant public health concern that can be addressed by actions at multiple levels.

A few months ago, the US National Academies of Sciences, Engineering and Medicine convened an expert committee to study the accessibility and affordability of hearing health care for adults in the United States. Using a set of guiding principles to help shape its work, the committee recommended key institutional, technological, and regulatory changes that would enable consumers to find and fully use the appropriate, affordable and high-quality services, technologies and support they need.

Why so few elderly have hearing aids is multifactorial, said the Baltimore ear expert. The average set of hearing aids costs close to $5,000, making it the third-largest purchase an older person makes after a house and a car. While cost is a big issue, it is not the only one,” said Lin.

“In most countries, you can’t buy a hearing aid on your own. You have to go to an audiologist who will decide if you need one and, if approved, one must travel back and forth for numerous visits in several months before it is fitted. Some people need these visits more, while others need them less.

Not everyone really needs an audiologist.

There have been significant improvements in hearing-aid technologies in the last 50 years, but the rate of use has remained static during this period.”

THE EDUCATIONAL requirements to become an audiologist differ by country.

In the US, one must earn a clinical doctorate after getting a bachelor’s degree. Here, one needs a two-year master’s degree after a bachelor’s degree. In Israel, people who feel they have hearing problems cannot go to a company and buy a hearing aid, even if they have the money to purchase it themselves. They must first go to an otolaryngologist (ear-nose-and-throat specialist) because a tumor or other medical problem could be the cause of the hearing loss). Numerous cases of hearing loss can result from a medical difficulty that can be remedied.

The queue for an ENT appointment is generally quite long, which deters some people from seeking a hearing aid. The Health Ministry covers the cost – through the basket of health services – of two cochlear implants for deaf children and for basic hearing aids for children and adults through age 30 (NIS 3,500 if eligibility for a hearing aid is approved). If one has a supplementary health fund policy, one can get an additional NIS 1,000 as well. People aged 31 to 64 with hearing problems can receive NIS 1,000 from the ministry, which does not cover the entire cost, and those aged 65 and over can get NIS 3,500 from a health fund supplementary insurance policies if they have approval due to their hearing problem. There have been applications for increasing hearing aid subsidies to those hearing disabled between the age of 31 and 64.

“If the problem were only the stigma of wearing a hearing aid, it would be easier to deal with. For some people, it is the cosmetic problem; for others it is access; while for yet others, it is price. But the business model of US hearing aid companies is wrong. They propagate the notion that everyone needs an audiologist and has to go frequently to them before they can get a hearing aid,” Lin continued. “They also push the most expensive models.”

There are “entrenched interests that encourage the status quo in America. In the short term it could be very disruptive if this were changed, but in the long term it would help. There are numerous public health groups that favor easing the access to hearing aids.”

Because of the awareness of the disability problem of large numbers of baby boomers and more elderly Americans, the White House is putting pressure on the authorities to change regulations said Lin, who noted that former president Bill Clinton is well aware of the problem and could ideally serve as a spokesman for wearing hearing aids because he suffers hearing loss from playing the saxophone as a young man.

“Health maintenance organizations observe the 50-year-old policy of Medicare that prevents the hearing disabled from getting hearing devices without going to an audiologist and without being completely deaf. The option was written out of regulations five decades ago and affects all HMO policies today.”

Asked if he thought being deaf was worse than being blind, Lin said it was difficult to answer, but the famous Helen Keller, who was both, said that her blindness disconnected her from things, while her deafness disconnected her from people.

AS FOR the link between hearing disability and dementia, Lin said they have a common pathological cause. One factor is that dementia can be caused by clogged blood vessels involving heart disease or diabetes.

But according to epidemiological studies, even after one controls for age, race, education and other factors, there is still a strong link, and there are three mechanistic influences.

The first, said Lin, is that with hearing loss, the brain has to cope with a garbled signal. It must expend energy on decoding this information rather than on thinking and building memory. The second is that when you constantly reduce stimulation to the brain, parts of the brain shrink faster.

Atrophy of the brain harms brain functions, and these have cascading effects. The third is that for people who cannot hear well are less socially engaged.

“They don’t go out as much; they suffer from loneliness. This is an important risk factor in dementia.”

While he believes that poor hearing can lead to dementia, Lin has not yet proven that treating hearing loss can impact these pathways and reduce the risk of Alzheimer’s, for example.

“From my perspective, I feel fairly confident that there is a link between hearing loss and dementia. I am not yet convinced whether treating hearing loss can do enough to reduce risk of dementia. Hearing loss may be just one factor. Maybe it couldn’t prevent dementia, but it could delay it or reduce the risk.”

A study in the Journal of the American Medical Association going back 23 years found more hearing loss in people with dementia.

That doesn’t prove the link on its own.

There have been case-controlled studies on people with hearing loss before they develop dementia.

“The vast majority of hearing loss is in older adults; it results from exposure to noise, and there is probably also a genetic aspect as well. But the genetics behind hearing loss in adulthood is not from one gene, but many genes.”

Lin is among the planners of a definitive study called ACHIEVE that is due to follow thousands of older people for years who do not have dementia. It will take two years just to recruit the participants at four centers around the US. They will undergo brain scans, hearing tests and scanning to see if they have plaque in the brain. Some of the participants will have hearing loss, while others will not.

“The NIH is considering our application for funding, and we hope it will be approved. Because it has not yet been proven, the ACHIEVE trial is so important.”

Linn is also involved in research about what can be done now about hearing loss – developing and testing new models of hearing care, making it affordable, taking hearing care out of clinic, going to the patient’s home and hearing centers.

“We will begin with lay health people who are trained by audiologists. They will spend an hour screening people in the community, promoting education about the subject and the use of non-hearing-aid devices such as iPhones that can help people without the need for audiologists. However, that model is not for everyone. Some of these over-thecounter amplification devices are useless, but others could be beneficial.”

Asked why a man of his young age is so interested in the elderly, Lin noted that many of his colleagues in the field are in their 30s and 40s.

“In public health, you study the issues that are challenging. With higher longevity rates promoted by 100 years of public health successes, we will have to learn how to deal with crush of older adults, including their hearing problems and dementia.”


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