In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin led a study that was the first to investigate the possible consequence of hearing loss on cognitive performance.
Volunteers with hearing loss took repeated cognitive tests, used to evaluate memory and thinking skills, over the span of six years. Hearing tests were also carried out 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 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 functioning. Moreover, those with hearing loss displayed characteristics of significant cognitive impairment 3.2 years sooner than those with normal hearing.
The research demonstrates 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 offered three reasons for the relationship between hearing loss and cognitive decline:
- Hearing loss can bring about social isolation, which is a known risk factor for cognitive decline.
- Hearing loss forces the brain to dedicate 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 reduced brain function.
Perhaps it’s a combination of all three. What is apparent is that, regardless of the cause, the connection 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, 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 prevent or overturn cognitive decline?
Can Hearing Aids Help?
Recall the three ways that hearing loss is thought to cause more rapid cognitive decline. Now, contemplate how hearing aids could address or correct those causes:
- People that use hearing aids regain their social confidence, become more socially active, and the problems of social isolation—and its contribution to brain decline—are lessened or removed.
- Hearing aids protect against the fatiguing impact 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 mainly theoretical, and the big question is: does wearing 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 prevent or minimize brain decline.
Stay tuned for the results, which we’ll address on our blog once published.