The relationship between hearing loss and dementia is nothing new, but it is gaining a stronger foothold. In fact, midlife hearing loss is one of many modifiable lifestyle factors that can potentially prevent more than one-third of dementia cases, according to a report presented at the Alzheimer’s Association International Conference.

But what is noteworthy is that midlife hearing loss accounted for 9% of the risk of dementia across the globe, making it the greatest single lifestyle factor contributing to dementia cases, according to the report.

But there is hope: Treating the hearing loss may actually reverse or slow cognitive decline.

“What we don’t know yet definitely is whether treating hearing loss will prevent cognitive decline,” said Jennifer Deal, an epidemiologist and gerontologist at Johns Hopkins University on the research team that explored the issue.

Beginning in November, the Lin Research Group at Johns Hopkins will build upon this pilot study and begin a clinical trial in which researchers will follow participants for three years, with results expected in five years, according to Next Avenue. The study targets participants between the ages of 70 and 84 who are at risk for cognitive decline, but are not yet cognitively impaired.

The Connection Between Hearing Loss and Dementia

The connection between hearing loss and dementia isn’t exactly clear, but researchers have their theories. One such theory is that hearing loss can result in social isolation, which is another significant risk factor for dementia.

“What keeps your brain healthy is a cognitively rich environment,” said Dr. Gil Livingston, professor of psychiatry at University College London and lead author of the report. “One of the easiest ways to get that is to talk. People who can’t hear often avoid complex social situations.”

In the pilot study, social improvements were noted among those who had their hearing loss treated with hearing aids. This group saw their social network grow, while those who didn’t receive hearing aids saw their social network decrease in a mere six months.

Addressing hearing loss and dementia isn’t as simple as providing hearing aids, though. Hearing aids can cost thousands of dollars, which limits access.

“People who get hearing aids can be quite a select group,” Deal said. “People who use hearing aids can be better cognitively, but it could be because of higher socioeconomic status, higher education and other reasons.”

Deal’s observation is especially pertinent, because low education came second on the report’s list of modifiable risk factors for dementia.

The way hearing works can be a reason for the connection between hearing loss and dementia, too. With hearing loss, the brain has to work harder to interpret degraded sound. Because of this hyperactivity, listeners may have more trouble remembering what they heard. Researchers believe that repeated efforts to decode sound may hinder the neural resources of those who struggle with hearing.

It’s important to note that the research and these theories pertain to age-related hearing loss, and don’t apply to those who list their hearing for other reasons. And while hearing loss and dementia strong correlate, hearing loss doesn’t necessarily cause dementia.

Even so, the research presents a strong case for seeing an audiologist once you reach middle age, if not for the potential to slow cognitive decline, then for an improved quality of life.