Hearing loss linked to accelerated brain tissue loss

January 22, 2014, Johns Hopkins University School of Medicine

Although the brain becomes smaller with age, the shrinkage seems to be fast-tracked in older adults with hearing loss, according to the results of a study by researchers from Johns Hopkins and the National Institute on Aging. The findings add to a growing list of health consequences associated with hearing loss, including increased risk of dementia, falls, hospitalizations, and diminished physical and mental health overall.

For the study, Frank Lin, M.D., Ph.D., and his colleagues used information from the ongoing Baltimore Longitudinal Study of Aging to compare changes over time between adults with normal hearing and adults with impaired hearing. The Baltimore Longitudinal Study of Aging was started in 1958 by the National Institute on Aging to track various health factors in thousands of men and women.

Previous research from other studies had linked with marked differences in brain structure compared to those with normal hearing, both in humans and animals. In particular, structures that process information from sound tended to be smaller in size in people and animals with impaired hearing. Lin, an assistant professor at the Johns Hopkins University schools of medicine and public health, says it was unknown, however, whether these brain structural differences occurred before or after hearing loss.

As part of the Baltimore Longitudinal Study of Aging, 126 participants underwent yearly (MRI) to track for up to 10 years. Each also had complete physicals at the time of the first MRI in 1994, including . At the starting point, 75 had normal hearing, and 51 had impaired hearing, with at least a 25-decibel loss.

After analyzing their MRIs over the following years, Lin and his colleagues, reporting in an upcoming issue of Neuroimage, say those participants whose hearing was already impaired at the start of the sub-study had accelerated rates of brain atrophy compared to 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 with those with normal hearing. Those with impaired hearing also had significantly more shrinkage in particular regions, including the superior, middle and inferior temporal gyri, brain structures responsible for processing sound and speech.

That structures responsible for sound and speech are affected in those with hearing loss wasn't a surprise, says Lin—shrinkage in those areas might simply be a consequence of an "impoverished" auditory cortex, which could become atrophied from lack of stimulation. However, he adds, these structures don't work in isolation, and their responsibilities don't end at sorting out sounds and language. The middle and inferior temporal gyri, for example, also play roles in memory and sensory integration and have been shown to be involved in the early stages of mild cognitive impairment and Alzheimer's disease.

"Our results suggest that hearing loss could be another 'hit' on the brain in many ways," Lin explains.

The study also gives some urgency to treating hearing loss rather than ignoring it. "If you want to address hearing loss well," Lin says, "you want to do it sooner rather than later. If hearing loss is potentially contributing to these differences we're seeing on MRI, you want to treat it before these brain structural changes take place."

Lin and his colleagues say they plan to eventually examine whether treating hearing loss early can reduce the risk of associated health problems.

Explore further: Hearing loss accelerates brain function decline in older adults

Related Stories

Hearing loss accelerates brain function decline in older adults

January 21, 2013
Older adults with hearing loss are more likely to develop problems thinking and remembering than older adults whose hearing is normal, according to a new study by hearing experts at Johns Hopkins.

Hearing loss linked to 3-fold risk of falling

February 27, 2012
Hearing loss has been linked with a variety of medical, social and cognitive ills, including dementia. However, a new study led by a Johns Hopkins researcher suggests that hearing loss may also be a risk factor for another ...

Obesity associated with higher risk of hearing loss in women

November 25, 2013
According to the World Health Organization, 360 million people have disabling hearing loss, a condition that is often considered to be an unavoidable side effect of aging. New research from Brigham and Women's Hospital (BWH) ...

Hearing aid gap: Millions who could benefit remain untreated

February 13, 2012
Though an estimated 26.7 million Americans age 50 and older have hearing loss, only about one in seven uses a hearing aid, according to a new study led by Johns Hopkins researchers.

One in five Americans has hearing loss: study

November 14, 2011
Nearly a fifth of all Americans 12 years or older have hearing loss so severe that it may make communication difficult, according to a new study led by Johns Hopkins researchers and published in the Nov. 14 Archives of Internal ...

Recommended for you

Women run faster after taking newly developed supplement, study finds

January 19, 2018
A new study found that women who took a specially prepared blend of minerals and nutrients for a month saw their 3-mile run times drop by almost a minute.

Americans are getting more sleep

January 19, 2018
Although more than one in three Americans still don't get enough sleep, a new analysis shows first signs of success in the fight for more shut eye. According to data from 181,335 respondents aged 15 and older who participated ...

Wine is good for you—to a point

January 18, 2018
The Mediterranean diet has become synonymous with healthy eating, but there's one thing in it that stands out: It's cool to drink wine.

Sleep better, lose weight?

January 17, 2018
(HealthDay)—Sleeplessness could cost you when it's time to stand on your bathroom scale, a new British study suggests.

Who uses phone apps to track sleep habits? Mostly the healthy and wealthy in US

January 16, 2018
The profile of most Americans who use popular mobile phone apps that track sleep habits is that they are relatively affluent, claim to eat well, and say they are in good health, even if some of them tend to smoke.

Improvements in mortality rates are slowed by rise in obesity in the United States

January 15, 2018
With countless medical advances and efforts to curb smoking, one might expect that life expectancy in the United States would improve. Yet according to recent studies, there's been a reduction in the rate of improvement in ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.