In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin guided a study which was the first to identify the possible impact of hearing loss on mental performance.
Research volunteers with hearing loss took recurring cognitive exams, used to evaluate memory and thinking skills, over the course of six years. Hearing tests were also carried out over the same time period.
What the investigators found was concerning: those with hearing loss had cognitive abilities that 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 associated to the severity of the hearing loss. The more severe the hearing loss, the greater impairment to brain function. Additionally, those with hearing loss exhibited characteristics of significant cognitive deterioration 3.2 years earlier than those with average hearing.
The research demonstrates a strong association between hearing loss and cognitive decline, but the question remains as to how hearing loss can cause cognitive decline.
How Hearing Loss Produces Cognitive Decline
Researchers have suggested three reasons for the link 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 invest 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 declined brain function.
Possibly it’s a combination of all three. What is evident is that, irrespective of the cause, the link between hearing loss and cognitive decline is powerful.
The concern now becomes, what can we do about it? Researchers estimate that 27 million Americans over age 50, including two-thirds of men and women aged 70 years and older, experience some form of hearing loss. Is there a way those with hearing loss can protect against or counter cognitive decline?
How Hearing Aids Could Help
Remember the three ways that hearing loss is believed to trigger hastened cognitive decline. Now, think about how hearing aids could address or correct those causes:
- People that use hearing aids gain back their social confidence, become more socially active, and the problems of social isolation—and its contribution to cognitive decline—are mitigated or eliminated.
- Hearing aids protect against the fatiguing impact of struggling to hear. Cognitive resources are freed up and available for memory and reasoning.
- Hearing aids deliver increased sound stimulation to the brain, helping to re-create neural connections.
Admittedly, this is only theoretical, and the big question is: does utilizing hearing aids, in fact, slow or protect against accelerated mental decline, and can we quantify 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 study 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.