Now Hear This: Hearing Loss Associated with Risk of Dementia

Hearing loss can have multiple negative consequences, the worst of which may be an increased risk of dementia.

"We can't say there is a causal relationship, but they are definitely connected," said Danai Fannin, Ph.D., an associate professor at North Carolina Central University(NCCU) and a licensed speech-language pathologist in the department of Communication Sciences and Disorders.

The worse the untreated hearing loss, the greater the risk of dementia, according to research from Johns Hopkins University.

• Individuals with mild hearing loss are twice as likely to develop dementia as those with normal hearing.
• Those with moderate hearing loss are three times as likely to develop dementia as those with normal hearing.
• Those with severe hearing loss are five times as likely to develop dementia as those with normal hearing.

Scientists caution that this association between hearing loss and dementia is not well understood but researchers at Columbia University have hypothesized reasons for the link. For one, increased cognitive load, which is extra mental effort needed to understand speech, can drain resources from other brain tasks.

"The cognitive reserve - the mental strength that helps people show fewer signs of cognitive decline - even if you have dementia, your cognitive reserve can help mitigate it," Fannin said.

That might not work, however, for people with untreated hearing loss.

"It takes more energy to listen and concentrate to try to figure out what people are saying," said Fannin. "You are using this cognitive energy just to understand speech."

Also, says Fannin, researchers suggest that there could be less auditory stimulation when there is untreated hearing loss. Hearing loss can lead to social isolation, again, meaning less stimulation to the brain. This social isolation may weaken thinking skills over time.

Neurodegeneration could also be accelerated if hearing loss triggers shrinkage in the auditory cortex, potentially fueling Alzheimer's-related changes throughout the brain, Fannin said.

The incidence of hearing loss increases with age. By age 65-74, roughly 33% of adults incur hearing loss. By age 75, that increases to 50%.

Most people do nothing about hearing loss

There are a few treatments for hearing loss: cochlear implant surgery (for those with moderate to severe hearing loss), amplification or environmental adjustments or hearing aids.

While cochlear impact surgery is expensive - $30,000 to $100,000 according to one estimate - hearing aids cost an average of $2,000 per ear. And prices for hearing aids have become more affordable since late 2022, when the U.S. Food and Drug Administration allowed people with mild to moderate hearing loss to purchase hearing aids over the counter and without a prescription.

Still, most people who have hearing loss don't do anything.

"Only 20% to 30% of people who have hearing loss actually use hearing aids," said Fannin.

Fannin speculate on why people avoid treatment.

First, typical age-related hearing loss occurs gradually and tends to start off with high pitched sounds, which are the sounds that allow listeners to separate the parts of words in certain languages like English.

"People think they are still hearing because they can hear a dog bark (a lower-pitched sound), but they are not hearing the high-pitched sounds for speech perception," said Fannin. "If they are in a roomful of people, those with hearing loss don't really understand what is being said and have to ask for repetition."

Second, there is a stigma about wearing hearing aids. "People feel it indicates they are getting older," said Fannin.

Regardless of the reason, the minority of the population that actually use hearing aids take an average of ten years after initial diagnosis to be fitted with their first set of hearing aids, Fannin said.