In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin guided a study that was the first to investigate the potential impact of hearing loss on mental performance.
Participants with hearing loss took repeated cognitive assessments, used to evaluate memory and thinking skills, over the span of six years. Hearing tests were also performed over the same time frame.
What the investigators discovered 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 related to the degree of the hearing loss. The more intense the hearing loss, the greater impairment to brain function. In addition, those with hearing loss displayed signals of significant cognitive impairment 3.2 years sooner than those with average hearing.
The research depicts a strong connection between hearing loss and cognitive decline, but the question persists as to how hearing loss can lead to cognitive decline.
How Hearing Loss Produces Cognitive Decline
Researchers have suggested three reasons for the association between hearing loss and cognitive decline:
- Hearing loss can lead to social isolation, which is a well-known risk factor for cognitive decline.
- Hearing loss causes the brain to expend too many resources to the processing of sound, at the expense of memory and thinking.
- A common underlying injury to the brain causes both hearing loss and reduced brain function.
Possibly it’s a collection of all three. What is clear is that, regardless of the cause, the connection between hearing loss and cognitive decline is powerful.
The question 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 form of hearing loss. Is there a way those with hearing loss can protect against or reverse cognitive decline?
Can Hearing Aids Help?
Remember the three ways that hearing loss is believed to cause more rapid cognitive decline. Now, think about how hearing aids could resolve or correct those causes:
- People with hearing aids boost their social confidence, become more socially active, and the side effects of social isolation—and its contribution to mental decline—are mitigated or eliminated.
- Hearing aids prevent the overtaxing impact of struggling to hear. Cognitive resources are freed up and available for memory and reasoning.
- Hearing aids deliver elevated 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 may be found in an upcoming study by Dr. Frank Lin, the head researcher of the initial study. Lin is currently working on the first clinical trial to examine whether hearing aids can be objectively measured to prevent or mitigate brain decline.
Stay tuned for the results, which we’ll address on our blog once published.