In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin guided a study which was the first to evaluate the possible consequence of hearing loss on mental function.
Research volunteers with hearing loss took recurring cognitive examinations, used to measure memory and thinking skills, over the course of six years. Hearing tests were also performed over the same period.
What the researchers found was concerning: the cognitive abilities of those with hearing loss decreased 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 those with hearing loss experience higher rates of cognitive decline—the decline was directly related to the intensity of the hearing loss. The more serious the hearing loss, the greater impairment to brain performance. Moreover, those with hearing loss exhibited signals of significant cognitive deterioration 3.2 years sooner than those with normal hearing.
The research reveals a deep association between hearing loss and cognitive decline, but the question remains as to how hearing loss can cause cognitive decline.
How Hearing Loss Creates Cognitive Decline
Researchers have offered three explanations for the association between hearing loss and cognitive decline:
- Hearing loss can lead to social isolation, which is a known risk factor for cognitive decline.
- Hearing loss forces the brain to devote 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 decreased brain function.
Perhaps it’s a blend of all three. What is apparent 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? Experts estimate that 27 million Americans over age 50, including 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 prevent or counter cognitive decline?
Can Hearing Aids Help?
Recall the three ways that hearing loss is considered to trigger hastened cognitive decline. Now, contemplate how hearing aids could deal with or correct those causes:
- Individuals with hearing aids gain back their social confidence, become more socially active, and the side effects of social isolation—and its contribution to brain decline—are mitigated or eliminated.
- Hearing aids protect against the overtaxing impact of struggling to hear. Cognitive resources are freed up for memory and reasoning.
- Hearing aids provide elevated sound stimulation to the brain, helping to re-establish neural connections.
Admittedly, this is mainly theoretical, and the big question is: does using 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 presently 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 of this research, which we’ll address on our blog once published.