Release Date: February 14, 2011
Dementia is a condition that affects millions of people. Seniors with hearing loss are more likely to develop dementia. However, a study by Johns Hopkins and the National Institute on Aging says it could lead to new ways to treat dementia.
The Link Between Hearing Loss and Dementia
The reason for the link is unknown. However, researchers think that a common cause and effect may be seen in both. It may be that people with hearing loss have the extra strain of decoding sounds. As a result, stressing the brain from the strain. This leaves people more at risk for dementia. Also, they believe that hearing loss makes people less social. This is a known risk factor for dementia and other cognitive disorders.
Whatever the cause, they think their findings may offer a starting point for treatment even as simple as hearing aids that could slow or prevent dementia by improving patients hearing.
Is There a Relationship?
Researchers have looked at what affects hearing loss, but few have looked at how hearing loss affects cognitive brain function, says study leader Frank Lin, M.D., Ph.D., assistant professor in the Division of Otology at Johns Hopkins University School of Medicine. There hasn’t been much talk between otologists and geriatricians, so it’s been unclear whether hearing loss and dementia are related.
To make the link, Lin used data from the Baltimore Longitudinal Study on Aging (BLSA). The BLSA, started by the National Institute on Aging in 1958, has tracked health factors in thousands of men and women over the years.
Current Research
The new study, in the February Archives of Neurology, was looking at 639 people. Their hearing and cognitive abilities went through assessment as part of the BLSA between 1990 and 1994. While about a quarter of the people had some hearing loss at the start of the study, none had dementia.
They did exams on these people every one to two years. By 2008, they could see the start of dementia in 58 of them. The researchers found that study participants with hearing loss at the beginning of the study were more likely to develop dementia by the end. In addition, compared with people with normal hearing, those with mild, moderate, and severe hearing loss had twofold, threefold, and fivefold, respectively, the risk of having dementia over time. So, the more hearing loss they had, the higher their risk for this memory-robbing disease.
Even after the researchers considered other factors that are linked to the risk of dementia, including diabetes, high blood pressure, age, sex, and race, Lin explains, hearing loss and dementia were still strongly connected.
A lot of people ignore hearing loss because it’s such a slow process as we age, Lin says. Even if people feel they are not seeing any effects, we’re showing that it may well be a more serious problem.
The research has support from the intramural research program of the National Institute on Aging.