In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin guided a study that was the first to investigate the possible impact of hearing loss on mental performance.
Participants with hearing loss took repeated cognitive tests, used to quantify memory and thinking skills, over the span of six years. Hearing tests were also conducted over the same period.
What the researchers discovered 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 all. Not only did those with hearing loss experience higher rates of cognitive decline—the decline was directly associated to the intensity of the hearing loss. The more serious the hearing loss, the greater impairment to brain function. Moreover, those with hearing loss presented signs of substantial cognitive deterioration 3.2 years earlier than those with normal hearing.
The research shows a deep connection between hearing loss and cognitive decline, but the question persists as to how hearing loss can create cognitive decline.
How Hearing Loss Triggers Cognitive Decline
Researchers have proposed three reasons for the association between hearing loss and cognitive decline:
- Hearing loss can lead to social isolation, which is a recognized risk factor for cognitive decline.
- Hearing loss causes 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 diminished brain function.
Possibly it’s a collection of all three. What is evident is that, regardless of the cause, the relationship between hearing loss and cognitive decline is powerful.
The question now becomes, what can be done about it? Researchers 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 reverse cognitive decline?
Can Hearing Aids Help?
Recall the three ways that hearing loss is believed to trigger accelerated cognitive decline. Now, think about how hearing aids could resolve or correct those causes:
- Individuals with hearing aids restore their social confidence, become more socially active, and the consequences of social isolation—and its contribution to mental decline—are lessened or eliminated.
- Hearing aids prevent the overtaxing effect of struggling to hear. Cognitive resources are freed up for memory and thinking.
- Hearing aids produce heightened sound stimulation to the brain, helping to re-create neural connections.
Admittedly, this is only 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 may be found in an forthcoming study by Dr. Frank Lin, the head researcher of the initial study. Lin is working on the first clinical trial to study whether hearing aids can be objectively measured to protect against or mitigate brain decline.
Stay tuned for the results, which we’ll cover on our blog once published.