In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin directed a study which was the first to evaluate the potential consequence of hearing loss on mental performance.
Research volunteers with hearing loss took recurring cognitive exams, used to assess memory and thinking skills, over the course of six years. Hearing tests were also completed over the same period.
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 everything. Not only did those with hearing loss suffer from higher rates of cognitive decline—the decline was directly related to the severity of the hearing loss. The more severe the hearing loss, the greater deterioration to brain functioning. Moreover, those with hearing loss showed evidence of substantial cognitive impairment 3.2 years sooner than those with normal hearing.
The research reveals a strong association between hearing loss and cognitive decline, but the question remains as to how hearing loss can lead to cognitive decline.
How Hearing Loss Triggers Cognitive Decline
Researchers have suggested three reasons for the connection between hearing loss and cognitive decline:
- Hearing loss can contribute to social isolation, which is a well-known risk factor for cognitive decline.
- Hearing loss forces the brain to commit 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 decreased brain function.
Perhaps it’s a blend of all three. What is evident is that, irrespective of the cause, the relationship 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, experience some type of hearing loss. Is there a way those with hearing loss can protect against or overturn cognitive decline?
Can Hearing Aids Help?
Recall the three ways that hearing loss is believed to trigger accelerated cognitive decline. Now, consider how hearing aids could deal with or correct those causes:
- Individuals that use hearing aids increase 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 effect of struggling to hear. Cognitive resources are freed up and available for memory and reasoning.
- Hearing aids deliver amplified sound stimulation to the brain, helping to re-create neural connections.
Admittedly, this is only theoretical, and the big question is: does wearing hearing aids, in fact, slow or protect against hastened mental decline, and can we quantify this?
The answer could be discovered in an forthcoming study by Dr. Frank Lin, the lead researcher of the initial study. Lin is presently working on the first clinical trial to study whether hearing aids can be objectively measured to protect against or alleviate brain decline.
Stay tuned for the results of this study, which we’ll address on our blog once published.