In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin led a study that was the first to review the potential impact of hearing loss on mental performance.
Research volunteers with hearing loss took recurring cognitive assessments, used to evaluate memory and thinking skills, over the span of six years. Hearing tests were also completed over the same time frame.
What the investigators discovered was concerning: those with hearing loss had cognitive abilities that diminished 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 linked to the extent of the hearing loss. The more extreme the hearing loss, the greater deterioration to brain performance. Additionally, those with hearing loss showed signs of significant cognitive deterioration 3.2 years earlier than those with average hearing.
The research demonstrates a deep connection 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 proposed three explanations for the relationship between hearing loss and cognitive decline:
- Hearing loss can bring about social isolation, which is a recognized risk factor for cognitive decline.
- Hearing loss forces the brain to dedicate too many resources to the processing of sound, at the expense of short term memory and thinking.
- A shared underlying trauma to the brain causes both hearing loss and diminished brain function.
Perhaps it’s a collection of all three. What is apparent is that, irrespective of the cause, the connection between hearing loss and cognitive decline is powerful.
The concern now becomes, what can be done about it? Experts estimate that 27 million Americans over age 50, including two-thirds of men and women aged 70 years and older, are suffering from some kind of hearing loss. Is there a way those with hearing loss can protect against or overturn cognitive decline?
Can Hearing Aids Help?
Remember the three ways that hearing loss is thought to cause hastened cognitive decline. Now, think about how hearing aids could resolve or correct those causes:
- Individuals that use hearing aids gain back their social confidence, become more socially active, and the consequences of social isolation—and its contribution to mental decline—are lessened or eliminated.
- Hearing aids protect against the fatiguing effect of struggling to hear. Mental resources are freed up for memory and reasoning.
- Hearing aids produce 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 prevent accelerated mental decline, and can we measure this?
The answer may be found 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 prevent or minimize brain decline.
Stay tuned for the results, which we’ll cover on our blog once published.