Understanding the Latest Findings in Hearing Health News
How hearing loss affects your brain has been in the news a lot lately. For example, you might have heard about the results of a groundbreaking 2023 study about hearing loss and cognitive decline.
You might even have seen headlines that claim hearing aids cut cognitive decline by 48%.
But articles about this type of scientific news often contain language that’s easy to gloss over or misinterpret. What does it mean when hearing loss and cognitive decline have been linked? When they’re associated, is that the same thing? What about when an article says they’re correlated?
Let’s look at some terminology, check out an example that involves your heart and your hearing, and then return to hearing health and brain health.
Basic Terms
Variables
When researchers want to study the relationship between two things that can be measured, they call them variables. No, we’re not wading into math territory here. Just know that “variables” means “the things being studied.” Hearing loss is a variable, as is cognitive decline. And researchers try as much as possible to consider any other variables in play and account for their effects on the situation.
Independent
Suppose you’re making cookies from scratch. You’re multitasking, so you’re making chocolate chip cookies and snickerdoodles.
Your two variables are cream of tartar and chocolate chips.
Already, you can probably tell one thing — in this situation, how much cream of tartar you use has nothing to do with how many chocolate chips you use. This means the variables are independent. One doesn’t depend on the other at all.
Associated or Linked
Those snickerdoodles were a hit, and you can see why — the perfect texture, height, and flavor. You decide a week later to make them again. The variables this time are cream of tartar and cookie rise.
You realize you have no cream of tartar. But really, how much does that matter? It’s a teaspoon and a half of measly powder.
The cookies come out kind of flat. You suspect it has something to do with leaving out the cream of tartar — you think it’s associated with (or linked with) flat snickerdoodles. But you’re not convinced (just play along).
Correlated
Being a curious person — and someone who loves baking — you decide to bake three more batches to try to understand this association. You’re going to test your variables.
One batch has no cream of tartar, one has the amount indicated in the recipe, and the third has twice the amount indicated in the recipe.
The first batch is the same flat cookie you made last time. The second batch is the height a snickerdoodle ought to be. The third is awfully lofty. You don’t trust it.
But you’ve decided cream of tartar and cookie height aren’t just associated, they’re correlated — a change in the first variable results in a predictable change in the other.
Causation
Here’s where things get complicated. If you know something is correlated, you still can’t assume one causes the other. Both variables might be affected by an unknown third variable.
This is where our baking example stops being as useful, because plenty has been written about how cream of tartar and baking soda work together to give snickerdoodles their characteristic lift. You can easily “prove” your theory that cream of tartar causes snickerdoodle cookies to have more lift.
Proving causation in research on the human body is much more difficult. Often, proving correlation or association is useful, even groundbreaking, and can inspire further research or influence your physician’s health recommendations.
Hearing Loss and Cardiovascular Disease
This is a classic example of association. There has long been a known association between two variables: cardiovascular disease (CVD) and hearing loss. But what does that mean, and why does it matter?
In one study, they found that hearing loss was more prevalent in people with CVD than in those who didn’t have CVD. They found an association between the variables CVD and hearing loss.
In another study, they found that hearing loss was more prevalent in people who simply have risk factors for CVD, such as smoking or diabetes. That’s another study finding an association between CVD and hearing loss!
When enough studies report findings like this, there starts to be a consensus. There must be an association — not necessarily a correlation — between CVD and hearing loss.
How is that helpful? Suppose your audiologist finds you have a hearing loss. If you know about the association between CVD and hearing loss, you can discuss your heart health with your physician, just in case your hearing loss indicates something about your cardiovascular system.
Hearing Loss and Cognitive Decline
Determining the Association
Before a groundbreaking study in 2011, researchers had suggested an association between the variables hearing loss and dementia. However, there had been no studies conducted specifically to determine whether there was.
The 2011 study didn’t just demonstrate an association between hearing loss and dementia — it also showed that the risk of developing dementia increased with the degree of hearing loss.
A couple of years later, another study showed that hearing loss is also associated with accelerated cognitive decline and cognitive impairment in older adults.
But just because these are associations, not something stronger such as correlation, doesn’t mean they’re not important. In fact, as of now, no correlation has been demonstrated between hearing loss and developing dementia. But that first study inspired other research up to the present, with encouraging results.
The ACHIEVE Study
Research on hearing loss and cognitive decline has long suggested that hearing aids might be able to slow down cognitive decline in older adults and that the benefits of hearing aids should be further investigated.
Dr. Frank Lin, the man behind the groundbreaking 2011 study, set out to do just that in his ACHIEVE study. Two sets of cognitively healthy 70-to-84-year-olds with untreated hearing loss were followed for three years. One group received hearing care, the other didn’t. The variables under study were hearing care and cognitive decline.
In their findings, hearing care, which included hearing aids, was associated with a 48% reduction in the rate of cognitive decline in older adults already at increased risk for cognitive decline.
Hearing care, at least in this study, seems to be related to a slowing down of cognitive decline in those at greater risk. On a related note, those at lower risk can’t expect the same slowing effect on cognitive decline.
With this association established, this first-of-its-kind study gives researchers a clearer picture of hearing care and cognitive decline — and a clearer direction for future research.
What’s also clear is that your hearing health affects your brain health — so contact us today if you suspect you or a loved one has hearing loss. It’s never too early to ensure you’re taking care of both.
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