In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin led a study which was the first to examine the potential impact of hearing loss on brain performance.
Participants with hearing loss took repeated cognitive assessments, used to assess memory and thinking skills, over the span of six years. Hearing tests were also conducted over the same time period.
What the investigators 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 all. Not only did people 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 impairment to brain performance. In addition, those with hearing loss showed indicators of significant cognitive impairment 3.2 years earlier than those with average hearing.
The research reveals 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 offered three explanations for the relationship between hearing loss and cognitive decline:
- Hearing loss can lead to social isolation, which is a recognized risk factor for cognitive decline.
- Hearing loss forces the brain to allocate too many resources to the processing of sound, at the expense of memory and thinking.
- A common underlying injury to the brain causes both hearing loss and decreased brain function.
Perhaps it’s a mix of all three. What is clear is that, regardless of the cause, the connection between hearing loss and cognitive decline is strong.
The concern 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, are suffering from some kind of hearing loss. Is there a way those with hearing loss can avoid or reverse cognitive decline?
Can Hearing Aids Help?
Recall the three ways that hearing loss is considered to cause more rapid cognitive decline. Now, consider how hearing aids could resolve or correct those causes:
- Individuals with hearing aids increase their social confidence, become more socially active, and the consequences of social isolation—and its contribution to cognitive decline—are lessened or removed.
- Hearing aids protect against the overtaxing effect of struggling to hear. Mental resources are freed up for memory and reasoning.
- Hearing aids produce boosted 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 prevent accelerated mental decline, and can we measure 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 mitigate brain decline.
Stay tuned for the results, which we’ll address on our blog once published.