Ignoring Hearing Problems Could Be Linked to Dementia

Hearing loss may increase your risk of developing dementia, scientists have warned. And according to new research, hearing aids may be able to prevent or delay the onset and progression of this condition.

Over 5 million Americans over the age of 65 live with dementia, according to 2014 data from the U.S. Centers for Disease Control and Prevention. Dementia comes in different forms—the most common of which is Alzheimer's disease—and is characterized by an impaired ability to remember, think and make decisions.

Numerous studies have found an association between hearing loss and cognitive decline, leading many to speculate that impaired hearing may be a risk factor for dementia. The mechanisms underlying this correlation are still unclear, but scientists are hopeful that it might lead to new treatment options in the future.

"There has long been interest in whether treating deafness with hearing aids can reduce the risk of developing dementia or at least delay the onset of dementia," Rob Howard, professor of old-age psychiatry at University College London, said in a statement.

In a recent study, published in the journal JAMA Otolaryngology - Head & Neck Surgery, researchers from the University of Southern Denmark assessed the associations between hearing loss and dementia in a cohort of 573,088 individuals over the age of 50. Participants were given a hearing assessment and followed up an average of 8.6 years later.

In the follow-up examinations, hearing loss was associated with an increased risk of dementia. However, out of those experiencing hearing loss, individuals who used hearing aids saw a significantly lower risk of dementia than those who did not.

"The authors found that people with hearing loss who did not use hearing aids has a 20 percent higher risk of dementia than those with normal hearing," Tom Dening, a professor of dementia research at the University of Nottingham, said in a statement.

"People who used hearing aids for their hearing loss did not have such a high risk (6%, which was only just significantly above the risk for normal hearing). This suggests that hearing aid use may help to protect against dementia."

However, while these results are promising, this association does not confirm that hearing aids can stop dementia. "Studies of this kind should be interpreted with care," Jason Warren, a professor of neurology at University College London, said in a statement.

"The brain changes associated with early dementia can affect hearing potentially some years before dementia is diagnosed and hearing loss (particularly if it is significant) acts as a 'cognitive stress test' that makes it more likely underlying dementia will be detected. In addition, people may be less likely to wear their hearing aids if they are developing cognitive problems. We should therefore be cautious about inferring that hearing loss causes dementia or that dementia can be prevented by wearing hearing aids."

Howard, too, said that, while these results are exciting, this correlation is not indicative of an underlying causal association. "It is always important to remember that association does not equal causation and to think about the potential differences between older people with hearing impairment who acquire and persist with the use of hearing aids versus those who don't," he said.

"So far, no randomised clinical trial has shown that encouraging deaf people to use hearing aids significantly reduces the development of dementia. We should probably wait until we have the results of such trials before recommending this as a way to prevent dementia. However, for those who find them acceptable and useful, hearing aids bring many other positive benefits to the lives of people with hearing impairment."

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