In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin guided a study that was the first to appraise the potential consequence of hearing loss on mental performance.
Participants with hearing loss took recurring cognitive examinations, used to assess memory and thinking skills, over the span of six years. Hearing tests were also carried out over the same period.
What the investigators 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 everything. Not only did those with hearing loss experience higher rates of cognitive decline—the decline was directly related to the extent of the hearing loss. The more extreme the hearing loss, the greater deterioration to brain function. Furthermore, those with hearing loss presented signs of substantial cognitive deterioration 3.2 years earlier than those with normal hearing.
The research shows a strong association between hearing loss and cognitive decline, but the question remains as to how hearing loss can result in cognitive decline.
How Hearing Loss Causes Cognitive Decline
Researchers have suggested three reasons for the relationship between hearing loss and cognitive decline:
- Hearing loss can result in social isolation, which is a known 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 common underlying trauma to the brain causes both hearing loss and declined brain function.
Possibly it’s a collection of all three. What is apparent is that, regardless of the cause, the connection between hearing loss and cognitive decline is powerful.
The concern now becomes, what can we do 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 protect against or reverse cognitive decline?
How Hearing Aids Could Help
Remember the three ways that hearing loss is thought to trigger 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 problems of social isolation—and its contribution to brain decline—are mitigated or removed.
- Hearing aids protect against the overtaxing effect of struggling to hear. Cognitive resources are freed up and available for memory and thinking.
- Hearing aids produce amplified 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 accelerated mental decline, and can we measure this?
The answer could be discovered in an forthcoming study by Dr. Frank Lin, the head 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 minimize brain decline.
Stay tuned for the results of this research, which we’ll cover on our blog once published.