In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin guided a study which was the first to analyze the possible consequence of hearing loss on mental function.
Volunteers with hearing loss took repeated cognitive examinations, used to quantify memory and thinking skills, over the course of six years. Hearing tests were also performed over the same time period.
What the researchers discovered was concerning: the cognitive abilities of those with hearing loss declined 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 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 functioning. Moreover, those with hearing loss presented indicators of appreciable cognitive impairment 3.2 years sooner than those with normal hearing.
The research shows a deep association between hearing loss and cognitive decline, but the question remains as to how hearing loss can lead to cognitive decline.
How Hearing Loss Triggers Cognitive Decline
Researchers have offered three explanations for the association between hearing loss and cognitive decline:
- Hearing loss can result in 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 short term memory and thinking.
- A shared underlying trauma to the brain causes both hearing loss and declined brain function.
Possibly it’s a combination of all three. What is apparent is that, irrespective 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 form of hearing loss. Is there a way those with hearing loss can protect against or overturn cognitive decline?
How Hearing Aids Could Help
Recall the three ways that hearing loss is thought to cause hastened cognitive decline. Now, consider how hearing aids could resolve or correct those causes:
- People with hearing aids regain their social confidence, become more socially active, and the consequences of social isolation—and its contribution to brain decline—are lessened or eliminated.
- Hearing aids prevent the overtaxing impact of struggling to hear. Cognitive resources are freed up for memory and reasoning.
- Hearing aids deliver increased sound stimulation to the brain, helping to re-establish neural connections.
Admittedly, this is mainly theoretical, and the big question is: does using hearing aids, in fact, slow or protect against hastened mental decline, and can we quantify this?
The answer could be discovered in an upcoming study by Dr. Frank Lin, the head researcher of the initial study. Lin is currently working on the first clinical trial to examine whether hearing aids can be objectively measured to protect against or minimize brain decline.
Stay tuned for the results of this study, which we’ll cover on our blog once published.