In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin led a study which was the first to evaluate the possible impact of hearing loss on cognitive performance.
Research volunteers with hearing loss took repeated cognitive tests, used to measure memory and thinking skills, over the length of six years. Hearing tests were also carried out over the same time period.
What the researchers found was concerning: the cognitive abilities of those with hearing loss 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 experience higher rates of cognitive decline—the decline was directly connected to the seriousness of the hearing loss. The more serious the hearing loss, the greater deterioration to brain functioning. In addition, those with hearing loss exhibited evidence of significant cognitive deterioration 3.2 years sooner than those with normal 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 Creates Cognitive Decline
Researchers have suggested three explanations for the correlation between hearing loss and cognitive decline:
- Hearing loss can result in social isolation, which is a recognized risk factor for cognitive decline.
- Hearing loss forces the brain to allocate too many resources to the processing of sound, at the expense of short term memory and thinking.
- A shared underlying injury to the brain causes both hearing loss and decreased brain function.
Perhaps it’s a mix of all three. What is evident is that, irrespective of the cause, the relationship between hearing loss and cognitive decline is strong.
The question now becomes, what can we do about it? Researchers estimate that 27 million Americans over age 50, including two-thirds of men and women aged 70 years and older, suffer from some form of hearing loss. Is there a way those with hearing loss can prevent or reverse cognitive decline?
How Hearing Aids Could Help
Recall the three ways that hearing loss is considered to cause accelerated cognitive decline. Now, consider how hearing aids could resolve or correct those causes:
- People with hearing aids increase their social confidence, become more socially active, and the problems of social isolation—and its contribution to mental decline—are lessened or removed.
- Hearing aids prevent the fatiguing impact of struggling to hear. Mental resources are freed up and available for memory and reasoning.
- Hearing aids generate amplified sound stimulation to the brain, helping to re-establish neural connections.
Admittedly, this is only theoretical, and the big question is: does utilizing hearing aids, in fact, slow or protect against accelerated mental decline, and can we quantify this?
The answer could be discovered in an forthcoming study by Dr. Frank Lin, the head researcher of the initial study. Lin is working on the first clinical trial to examine whether hearing aids can be objectively measured to protect against or minimize brain decline.
Stay tuned for the results of this research, which we’ll cover on our blog once published.