In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin directed a study that was the first to appraise the possible consequence of hearing loss on mental performance.
Volunteers with hearing loss took repeated cognitive examinations, used to quantify memory and thinking skills, over the course of six years. Hearing tests were also performed over the same time frame.
What the researchers discovered was concerning: the cognitive abilities of those with hearing loss 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 experience higher rates of cognitive decline—the decline was directly connected to the severity of the hearing loss. The more serious the hearing loss, the greater impairment to brain function. In addition, those with hearing loss showed indications of significant cognitive impairment 3.2 years earlier than those with average hearing.
The research reveals a strong connection between hearing loss and cognitive decline, but the question persists as to how hearing loss can result in cognitive decline.
How Hearing Loss Produces Cognitive Decline
Researchers have proposed three reasons for the relationship between hearing loss and cognitive decline:
- Hearing loss can lead to social isolation, which is a known risk factor for cognitive decline.
- Hearing loss causes the brain to commit 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 reduced brain function.
Perhaps it’s a mix of all three. What is evident is that, regardless of the cause, the relationship between hearing loss and cognitive decline is strong.
The concern now becomes, what can be done about it? Experts estimate that 27 million Americans over age 50, among them two-thirds of men and women aged 70 years and older, are afflicted by some type of hearing loss. Is there a way those with hearing loss can protect against or slow cognitive decline?
How Hearing Aids Could Help
Remember the three ways that hearing loss is believed to trigger accelerated cognitive decline. Now, think about how hearing aids could resolve or correct those causes:
- Individuals with hearing aids restore their social confidence, become more socially active, and the side effects of social isolation—and its contribution to cognitive decline—are lessened or removed.
- Hearing aids protect against the overtaxing impact of struggling to hear. Mental resources are freed up and available for memory and reasoning.
- Hearing aids present elevated sound stimulation to the brain, helping to re-establish neural connections.
Admittedly, this is mainly theoretical, and the big question is: does utilizing hearing aids, in fact, slow or prevent hastened 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 presently working on the first clinical trial to examine whether hearing aids can be objectively measured to protect against or mitigate brain decline.
Stay tuned for the results of this research, which we’ll address on our blog once published.