hearing loss and dementiaHearing Loss and Dementia

How hearing aids can help to prevent memory loss

Hearing loss isn’t just an inconvenience. It can be harmful the your brain too.

Seniors with hearing loss are at a higher risk for developing dementia over time than those with normal hearing. It is common knowledge that the brain becomes smaller with age, however, the shrinkage happens more quickly in older adults with hearing loss, according to the results of a study by researchers from Johns Hopkins and the National Institute on Aging. These findings add to a growing list of health consequences associated with hearing loss, including increased risk of dementia, falls, hospitalizations, and poor physical and mental health.

According to the American Speech-Language-Hearing Association, more than 30 percent of people over the age of 65 have some type of hearing loss, and 14 percent of people between 45 and 64 do as well. Close to 8 million people between the ages of 18 and 44 have hearing loss.

 “The general perception is that hearing loss is a relatively inconsequential part of aging, “says Frank Lin, M.D., an otologist and epidemiologist at Johns Hopkins University, “but recent findings suggest that it may play a much more important role in brain health than we’ve previously thought. “

 Information from the ongoing Baltimore Longitudinal Study of Aging compared brain changes for up to 10 years for individuals with normal hearing and impaired hearing of at least 25 decibels. After analyzing MRI’s over the years, Lin and his colleagues determined that the study participants whose hearing was already impaired at the start of the study had accelerated rates of brain atrophy compared to those with normal hearing. Those with impaired hearing lost more brain tissue each year compared to those with normal hearing. Those with impaired hearing also had significantly more shrinkage in the regions of the brain that process sound and speech. The more hearing loss the individuals had, the higher the risk for developing dementia.

The structures responsible for sound and speech are affected in those with hearing loss because that region of the brain could become atrophied from lack of stimulation. Lin also explained that these structures don’t work in isolation, and their responsibilities do not end at sorting out sounds and language. The gyri of the brain also play roles in memory and sensory integration, and have been shown to be involved in the early stages of dementia and Alzheimer’s disease.

 The study also gives some urgency to treat hearing loss rather than ignoring it. If hearing loss is potentially contributing to these differences, you want to treat it before the brain structural changes take place.

The research was supported by the intramural research program of the National Institute on Aging, the National Institutes of Health’s National Institute on Deafness and other Communication Disorders (K23DC011279), a Triological Society/American College of Surgeons Clinical Scientists Development Award and the Eleanor Schwartz Charitable Foundation. Susan Resnick, Ph.D., of the National Institute on Aging was the study’s senior investigator. Michael A. Kraut, M.D., Ph.D., of Johns Hopkins; and Luigi Ferrucci, M.D., Ph.D., and Yang An, M.S>, both of the National Institute on Aging, also contributed to the research.