In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin led a study that was the first to identify the potential consequence of hearing loss on brain function.
Research volunteers with hearing loss took repeated cognitive tests, used to assess memory and thinking skills, over the course of six years. Hearing tests were also performed over the same time period.
What the researchers found 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 age, high blood pressure, and diabetes.
But that wasn’t all. Not only did people with hearing loss suffer from higher rates of cognitive decline—the decline was directly related to the extent of the hearing loss. The more serious the hearing loss, the greater deterioration to brain functioning. Moreover, those with hearing loss showed evidence of appreciable cognitive deterioration 3.2 years sooner than those with average hearing.
The research depicts a strong connection between hearing loss and cognitive decline, but the question remains as to how hearing loss can trigger cognitive decline.
How Hearing Loss Creates Cognitive Decline
Researchers have offered three reasons for the connection between hearing loss and cognitive decline:
- Hearing loss can result in social isolation, which is a recognized risk factor for cognitive decline.
- Hearing loss causes the brain to devote 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 diminished brain function.
Possibly it’s a blend of all three. What is clear is that, irrespective of the cause, the link between hearing loss and cognitive decline is powerful.
The concern now becomes, what can we do about it? Researchers estimate that 27 million Americans over age 50, including two-thirds of men and women aged 70 years and older, suffer from some kind of hearing loss. Is there a way those with hearing loss can prevent or counter cognitive decline?
Can Hearing Aids Help?
Recall the three ways that hearing loss is believed to trigger accelerated cognitive decline. Now, contemplate how hearing aids could resolve or correct those causes:
- People with hearing aids increase their social confidence, become more socially active, and the side effects of social isolation—and its contribution to brain decline—are mitigated or removed.
- Hearing aids protect against the fatiguing impact of struggling to hear. Mental resources are freed up and available for memory and reasoning.
- Hearing aids produce boosted sound stimulation to the brain, helping to re-create neural connections.
Admittedly, this is only theoretical, and the big question is: does wearing hearing aids, in fact, slow or protect against hastened mental decline, and can we measure this?
The answer could be found in an forthcoming study by Dr. Frank Lin, the head 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 alleviate brain decline.
Stay tuned for the results, which we’ll cover on our blog once published.