In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin directed a study that was the first to investigate the possible consequence of hearing loss on mental function.
Research volunteers with hearing loss took repeated cognitive exams, used to measure memory and thinking skills, over the course of six years. Hearing tests were also performed over the same time frame.
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 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 associated to the seriousness of the hearing loss. The more intense the hearing loss, the greater deterioration to brain performance. Furthermore, those with hearing loss showed evidence of appreciable cognitive deterioration 3.2 years earlier than those with average hearing.
The research demonstrates a deep connection between hearing loss and cognitive decline, but the question remains as to how hearing loss can create cognitive decline.
How Hearing Loss Produces Cognitive Decline
Researchers have suggested three reasons for the association between hearing loss and cognitive decline:
- Hearing loss can bring about social isolation, which is a well-known risk factor for cognitive decline.
- Hearing loss forces the brain to devote too many resources to the processing of sound, at the expense of short term memory and thinking.
- A common underlying trauma to the brain causes both hearing loss and declined brain function.
Possibly it’s a blend of all three. What is apparent is that, regardless of the cause, the link between hearing loss and cognitive decline is powerful.
The question now becomes, what can be done about it? Experts estimate that 27 million Americans over age 50, including two-thirds of men and women aged 70 years and older, are afflicted by some type of hearing loss. Is there a way those with hearing loss can avoid or slow cognitive decline?
Can Hearing Aids Help?
Recall the three ways that hearing loss is believed to cause accelerated cognitive decline. Now, contemplate how hearing aids could address or correct those causes:
- People with hearing aids boost their social confidence, become more socially active, and the side effects of social isolation—and its contribution to brain 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 yield increased sound stimulation to the brain, helping to re-establish neural connections.
Admittedly, this is only 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 found in an forthcoming study by Dr. Frank Lin, the lead researcher of the initial study. Lin is working on the first clinical trial to examine whether hearing aids can be objectively measured to protect against or alleviate brain decline.
Stay tuned for the results of this research, which we’ll cover on our blog once published.