According to a recent study published in the medical journal Archives of Neurology, adults with hearing loss are significantly more likely than adults with normal hearing to develop dementia. The study was conducted by researchers at Johns Hopkins and the National Institute on Aging. The study found that the greater the hearing loss the higher the risk of dementia and may open a new avenue of research into dementia and Alzheimer’s disease. Men and women in the study who experienced severe hearing loss were five times more likely to develop dementia than those with normal hearing. But even mild hearing loss doubled the risk of dementia.
The study followed 639 people ages 36 to 90 who initially did not have dementia, logic and language that interferes with daily living. The volunteers were tested for hearing loss and dementia every two years for nearly two decades.Researchers found that those with hearing loss at the beginning of the study were much more likely to develop dementia by the end, even after taking into account age and other risk factors. The risk of dementia only began to rise once hearing loss began to interfere with the ability to communicate. The study also found that hearing loss increased the risk of Alzheimer’s disease, but the two were not as strongly linked as hearing loss and dementia.
The social isolation often caused by hearing loss can aid in the development of dementia. Also, it is quite possible that auditory deprivation may be related to the increase in dementia. Auditory deprivation occurs because of inadequate stimulation of the auditory system. With auditory deprivation, a person gradually loses their ability to comprehend speech making communication even more frustrating. This is why it is important to wear hearing aids at the early onset of hearing loss to continue stimulation of the entire auditory system.
“The brain might have to reallocate resources to help with hearing at the expense of cognition,” says the lead researcher, Frank R. Lin, M.D., an ear surgeon at Johns Hopkins Hospital in Baltimore. That may explain in part why straining to hear conversations over background noise in a loud restaurant can be mentally exhausting for anyone, hard of hearing or not, he adds.
The findings suggest that poor hearing is a “harbinger of impending dementia,” says George Gates, M.D., a hearing expert at the University of Washington in Seattle, who was not involved in the new study but whose own research has demonstrated a link between the two conditions.”We listen with our ears but hear with our brains,” Gates says. “It is simply not possible to separate audition and cognition.
“Lin says that hearing loss has an enormous impact on the lives of his patients and their family members. “Yet because it is such a slow and insidious process, it is often left ignored and untreated.
“There is no cure for dementia, and there are no surefire ways of preventing it. Gates isn’t optimistic that restoring hearing can affect the course of dementia. However, if treatments and prevention strategies for dementia do become available in the future, he says, hearing loss could play an important role in early detection.
Lin and his colleagues have begun researching the effect of hearing aids on the risk of dementia. “Whether or not it can help dementia, we don’t know yet,” he says. “But in the meantime, there’s no reason not to take your hearing loss seriously and pursue some type of treatment.”