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 mental performance.
Volunteers with hearing loss took repeated cognitive exams, used to evaluate memory and thinking skills, over the length of six years. Hearing tests were also conducted over the same time frame.
What the investigators found 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 age, high blood pressure, and diabetes.
But that wasn’t everything. 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 severe the hearing loss, the greater deterioration to brain performance. Furthermore, those with hearing loss displayed signals of significant cognitive deterioration 3.2 years sooner than those with normal hearing.
The research shows a strong association between hearing loss and cognitive decline, but the question remains as to how hearing loss can trigger cognitive decline.
How Hearing Loss Causes Cognitive Decline
Researchers have proposed three explanations for the correlation between hearing loss and cognitive decline:
- Hearing loss can bring about social isolation, which is a recognized risk factor for cognitive decline.
- Hearing loss forces the brain to commit too many resources to the processing of sound, at the expense of memory and thinking.
- A shared underlying trauma to the brain causes both hearing loss and reduced brain function.
Perhaps it’s a blend of all three. What is apparent 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, including two-thirds of men and women aged 70 years and older, are afflicted by some kind of hearing loss. Is there a way those with hearing loss can protect against or counter cognitive decline?
Can Hearing Aids Help?
Remember the three ways that hearing loss is believed to trigger hastened cognitive decline. Now, think about how hearing aids could deal with or correct those causes:
- People with hearing aids increase their social confidence, become more socially active, and the effects of social isolation—and its contribution to brain 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 thinking.
- Hearing aids yield elevated sound stimulation to the brain, helping to re-create neural connections.
Admittedly, this is mainly theoretical, and the big question is: does utilizing hearing aids, in fact, slow or prevent accelerated mental decline, and can we measure this?
The answer could be discovered in an upcoming study by Dr. Frank Lin, the head 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 mitigate brain decline.
Stay tuned for the results, which we’ll address on our blog once published.