In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin led a study which was the first to measure the possible impact of hearing loss on mental performance.
Research volunteers with hearing loss took recurring cognitive exams, used to measure memory and thinking skills, over the span of six years. Hearing tests were also conducted over the same time frame.
What the researchers discovered was concerning: those with hearing loss had cognitive abilities that declined 30 to 40 percent faster than those with normal hearing, even after accounting for other contributing factors like high blood pressure, age, and diabetes.
But that wasn’t all. Not only did people with hearing loss suffer from higher rates of cognitive decline—the decline was directly related to the severity of the hearing loss. The more serious the hearing loss, the greater impairment to brain function. Additionally, those with hearing loss showed signs of significant cognitive deterioration 3.2 years sooner than those with average hearing.
The research reveals a strong association between hearing loss and cognitive decline, but the question persists as to how hearing loss can create cognitive decline.
How Hearing Loss Triggers Cognitive Decline
Researchers have suggested three explanations for the relationship between hearing loss and cognitive decline:
- Hearing loss can lead to social isolation, which is a recognized risk factor for cognitive decline.
- Hearing loss forces the brain to devote too many resources to the processing of sound, at the expense of short term memory and thinking.
- A common underlying injury to the brain causes both hearing loss and reduced brain function.
Perhaps it’s a combination of all three. What is clear is that, irrespective of the cause, the relationship between hearing loss and cognitive decline is strong.
The concern now becomes, what can be done about it? Researchers estimate that 27 million Americans over age 50, among them two-thirds of men and women aged 70 years and older, experience some kind of hearing loss. Is there a way those with hearing loss can avoid or counter cognitive decline?
Can Hearing Aids Help?
Recall the three ways that hearing loss is considered to cause more rapid cognitive decline. Now, contemplate how hearing aids could address or correct those causes:
- Individuals that use hearing aids restore their social confidence, become more socially active, and the consequences of social isolation—and its contribution to mental decline—are mitigated or removed.
- Hearing aids prevent the overtaxing impact of struggling to hear. Mental resources are freed up and available for memory and thinking.
- Hearing aids present boosted sound stimulation to the brain, helping to re-establish neural connections.
Admittedly, this is mainly theoretical, and the big question is: does wearing hearing aids, in fact, slow or protect against accelerated mental decline, and can we quantify this?
The answer could be found in an forthcoming study by Dr. Frank Lin, the head researcher of the initial study. Lin is currently working on the first clinical trial to study whether hearing aids can be objectively measured to prevent or mitigate brain decline.
Stay tuned for the results, which we’ll cover on our blog once published.