In 2013, Johns Hopkins University researcher and epidemiologist Dr. Frank Lin guided a study which was the first to evaluate the potential impact of hearing loss on mental function.
Participants with hearing loss took repeated cognitive tests, used to evaluate memory and thinking skills, over the length of six years. Hearing tests were also conducted over the same period.
What the investigators found was concerning: those with hearing loss had cognitive abilities that 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 those with hearing loss experience higher rates of cognitive decline—the decline was directly linked to the seriousness of the hearing loss. The more intense the hearing loss, the greater deterioration to brain function. In addition, those with hearing loss presented characteristics of substantial cognitive impairment 3.2 years sooner than those with normal hearing.
The research depicts a strong connection between hearing loss and cognitive decline, but the question remains as to how hearing loss can create cognitive decline.
How Hearing Loss Causes Cognitive Decline
Researchers have suggested three explanations for the link between hearing loss and cognitive decline:
- Hearing loss can contribute to social isolation, which is a known risk factor for cognitive decline.
- Hearing loss causes the brain to expend 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, regardless of the cause, the connection between hearing loss and cognitive decline is strong.
The question now becomes, what can we do 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 type of hearing loss. Is there a way those with hearing loss can prevent or reverse 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 deal with or correct those causes:
- Individuals with hearing aids increase 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 fatiguing effect of struggling to hear. Cognitive resources are freed up for memory and reasoning.
- 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 wearing hearing aids, in fact, slow or prevent hastened mental decline, and can we measure this?
The answer could be found in an upcoming 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 study, which we’ll cover on our blog once published.