In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin led a study that was the first to evaluate the potential consequence of hearing loss on brain function.
Research volunteers with hearing loss took recurring cognitive examinations, used to assess memory and thinking skills, over the course of six years. Hearing tests were also completed over the same period.
What the researchers found 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 suffer from higher rates of cognitive decline—the decline was directly linked to the seriousness of the hearing loss. The more serious the hearing loss, the greater impairment to brain functioning. Furthermore, those with hearing loss displayed indicators of significant cognitive impairment 3.2 years sooner than those with normal hearing.
The research demonstrates a deep association between hearing loss and cognitive decline, but the question persists as to how hearing loss can result in cognitive decline.
How Hearing Loss Produces Cognitive Decline
Researchers have offered three reasons for the correlation 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 memory and thinking.
- A common underlying injury to the brain causes both hearing loss and decreased brain function.
Possibly it’s a mix of all three. What is clear is that, regardless of the cause, the relationship 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, including 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 counter cognitive decline?
Can Hearing Aids Help?
Recall the three ways that hearing loss is believed to trigger more rapid cognitive decline. Now, contemplate how hearing aids could resolve or correct those causes:
- People that use hearing aids boost their social confidence, become more socially active, and the consequences of social isolation—and its contribution to brain decline—are mitigated or removed.
- Hearing aids prevent the overtaxing impact of struggling to hear. Cognitive resources are freed up for memory and thinking.
- Hearing aids present increased sound stimulation to the brain, helping to re-create 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 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 of this study, which we’ll cover on our blog once published.