In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin guided a study that was the first to appraise the potential consequence of hearing loss on cognitive performance.
Participants with hearing loss took recurring cognitive examinations, used to evaluate memory and thinking skills, over the length of six years. Hearing tests were also completed over the same time frame.
What the researchers discovered 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 everything. Not only did those with hearing loss experience higher rates of cognitive decline—the decline was directly associated to the extent of the hearing loss. The more extreme the hearing loss, the greater impairment to brain function. Furthermore, those with hearing loss exhibited indications of substantial cognitive impairment 3.2 years earlier than those with average hearing.
The research shows 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 Triggers Cognitive Decline
Researchers have offered 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 trauma to the brain causes both hearing loss and diminished brain function.
Perhaps it’s a mixture of all three. What is clear is that, regardless of the cause, the link between hearing loss and cognitive decline is strong.
The concern 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 type of hearing loss. Is there a way those with hearing loss can avoid or overturn cognitive decline?
Can Hearing Aids Help?
Remember the three ways that hearing loss is thought to cause hastened cognitive decline. Now, consider how hearing aids could resolve or correct those causes:
- Individuals that use hearing aids restore their social confidence, become more socially active, and the side effects of social isolation—and its contribution to mental decline—are lessened or removed.
- Hearing aids prevent the fatiguing effect of struggling to hear. Mental resources are freed up for memory and thinking.
- Hearing aids yield boosted sound stimulation to the brain, helping to re-create neural connections.
Admittedly, this is mainly theoretical, and the big question is: does using hearing aids, in fact, slow or prevent hastened mental decline, and can we measure this?
The answer could be found in an upcoming study by Dr. Frank Lin, the lead researcher of the initial study. Lin is working on the first clinical trial to examine whether hearing aids can be objectively measured to protect against or minimize brain decline.
Stay tuned for the results of this research, which we’ll cover on our blog once published.