John Hopkins Bloomberg Public School of Health : Hearing Loss and the Dementia Connection
PublishedNovember 12, 2021
Hearing loss doesn’t just mean an older adult needs to turn up the TV. It’s been linked to a range of health problems, including dementia.
The latest aging research not only shows the two are connected, it’s also leading scientists to believe that hearing loss may actually be a cause of dementia.
This emerging area of research has huge implications, says Frank Lin, MD, PhD ’08, director of the Cochlear Center for Hearing and Public Health at the Bloomberg School. Some 37.5 million Americans have trouble hearing, according to the National Institute on Deafness and Other Communication Disorders.
A key question researchers have: Could hearing aids reduce the risk of a person developing dementia?
Lin explains the connection between the two conditions and where the science is headed.
Hearing loss and the brain
If you have hearing loss, you have a greater chance of developing dementia, according to a 2020 Lancet commission report that lists hearing loss as one of the top risk factors for dementia.
Brain strain and social isolation
Hearing loss can make the brain work harder, forcing it to strain to hear and fill in the gaps. That comes at the expense of other thinking and memory systems. Another possibility: Hearing loss causes the aging brain to shrink more quickly. A third possibility is that hearing loss leads people to be less socially engaged, which is hugely important to remaining intellectually stimulated. If you can't hear very well, you may not go out as much, so the brain is less engaged and active.
Quantifying hearing loss’s impact
Hearing loss is estimated to account for 8% of dementia cases. This means that hearing loss may be responsible for 800,000 of the nearly 10 million new cases of dementia diagnosed each year.
Reducing the risk of dementia
Johns Hopkins is leading a large National Institute on Aging study to see if hearing aids can safeguard seniors’ mental processes. The study has multiple locations and has recruited nearly 1,000 people ages 70–84 with hearing loss. One group is provided hearing aids, while another group receives aging education. By early 2023, the study should provide definitive results on whether treating hearing loss will reduce the risk of cognitive decline. In essence, we’ll know whether the use of hearing aids can potentially reduce brain aging and the risk of dementia.
Other effects on health
Hearing loss has long-term effects on health. It’s believed to increase the risk for falls and depression. It also leads to higher health care costs: People with hearing loss have, over 10 years, a 47% increased rate of hospitalization.
Frank R. Lin, MD, PhD, is the director of the Cochlear Center for Hearing and Public Health. He is a professor of Otolaryngology and Medicine at the Johns Hopkins School of Medicine as well as a professor of Mental Health and Epidemiology at the Johns Hopkins Bloomberg School of Public Health.