Turning up the volume when our favorite song begins playing. Navigating a busy commute. Strolling past a construction site. These three seemingly different things share a very important similarity: they’re all normal parts of daily life that can cause subtle hearing loss over time.
In fact, it’s things like this that concern hearing experts the most. Many of us forget to protect our ears from short-term exposure to loud noises that we experience every day. We become so accustomed to them that we forget the dangers they pose to our ears.
The result is that later in life, we suffer from hearing problems. Worse, research is finding that those hearing problems may be associated with a secondary health issue: cognitive impairment.
Exploring The Connection: Why Hearing Loss Could Be a Symptom of Cognitive Decline
In the results of a study published last year, researchers found that a specific type of hearing loss was often associated with mild cognitive decline (MCI). MCI is characterized by difficulties with memory, language, thinking, and judgment that exceed those normally associated with aging. MCI is an early indicator of possible dementia - a general term referring to a decline in mental capacities. Dementia affects around 50 million people worldwide and includes illnesses like Alzheimer's.
During the study, the researchers analyzed data collected on two types of age-related hearing loss: peripheral and central. Peripheral age-related hearing loss is caused by problems in the functionality of the inner ear and the nerves related to hearing. Central hearing loss, however, is caused by the brain’s impaired ability to process sound. As a result, people suffering from central hearing loss cannot always comprehend the meaning of what they hear.
At the end of the study, three-quarters of the participants with central hearing loss had MCI. That’s compared to 60 percent of those with no hearing loss or peripheral hearing loss.
When discussing these results, one researcher stated, “These preliminary results suggest that central hearing loss may share the same progressive loss of functioning in brain cells that occurs in cognitive decline, rather than the sensory deprivation that happens with peripheral hearing loss.”
In other words, there is a correlation between central hearing loss and overall cognitive decline.
Understanding These Results: How Hearing Loss Connects to Cognitive Decline
At first glance, these results can be confusing. We tend to think of the brain and the ear as completely separate entities. How could their decline be correlated?
The researchers explained as part of their study that, “The primary auditory cortex is the gateway to cortical processing of auditory input, since it receives information from the ascending auditory pathway. There are age-related changes in the primary auditory cortex. The memory areas are typically in the temporal cortex. Aging may involve both areas simultaneously.”
That’s a lot of medical jargon! So let’s break it down:
- The auditory cortex is the part of the temporal lobe that processes auditory information.
- 'Cortical processing' refers to the way in which the brain engages in cognitive behaviors and responses.
- Auditory input refers to the sounds being processed by the ear and brain.
Essentially, the researchers are saying that the brain is essential to processing soundwaves, analyzing and deciphering them, and determining a proper response to what we hear. Aging, however, creates changes in both the brain and the ears themselves, affecting cognitive functions as well as the ability to hear. The changes are referred to as neurodegeneration — the loss or death of neurons in the brain.
More Than an Aging Problem: Minor Hearing Loss Makes a Big Difference
Hearing loss affects approximately 30 percent of the U.S. population aged 60 to 69 years. It increases to 63 percent among people aged 70 years and over. For those older than 60 years of age, the risk of dementia is closely related to the severity of hearing loss.
But remember: hearing loss does not begin later in life. It begins early, and accumulates over time - and that affects the brain, too.
In addition to studying hearing loss and cognitive decline, researchers have found that in healthy young brains, only the left side of the brain processes sound and “translates” it into understandable languages. But when hearing loss develops, the right side of the brain begins to kick in and help process sound.
The problem is that normally, this would not happen until around the age of 50. Yet even a small amount of hearing loss forces the right side of the brain to “tune in” to the hearing process. As a result, experts now believe that this puts extra stress on the brain. It creates a situation where the brain expends extra energy translating sound and allowing us to hear and listen to the world around us. As a result, it drains cognitive resources that would otherwise be used for things such as memory development.
Worse still, once this process begins, it creates a vicious negative cycle of the hearing centers of the brain growing exhausted; of hearing capacity continuing to drop; and of cognitive decline. And the more cognitive abilities decline, the greater the risk of dementia.
Addressing Hearing Loss: What this Research Means For You
Unsurprisingly, losses of hearing and cognitive function are massive. Hearing loss by itself can lead to social isolation. And social isolation and loneliness have been linked to numerous adverse physical and mental health outcomes, including dementia. In other words, social isolation leads to further cognitive decline.
Taking action to address hearing loss early is the key to minimizing the risk of every health problem associated with hearing loss and MCI. And action includes the following:
- Protect your ears. Even a small amount of hearing loss — one you may not even be aware of — taxes your brain and can raise the risk of dementia later in life. Rather than letting this hearing loss accumulate, consider wearing protective headgear to block out loud everyday sounds. Additionally, avoid blasting your favorite music at high levels, particularly through headphones.
- Know your family history. A family history of either dementia or hearing loss can mean you have an increased risk of developing them as well. Knowing this history and reporting it to a doctor is crucial.
- Have regular evaluations and hearing tests. Meeting with a medical team (including a PCP and hearing expert) is a critical part of treating hearing loss as it develops. Ear doctors specifically can run tests to determine your specific hearing loss needs, and will prescribe lifestyle adjustments and tools alike to improve your quality of life - now and in the future.
Still have questions? Do you have specific concerns about your own hearing needs? We’re here to help! Since 1949, Hearing Unlimited, Inc. has specialized in addressing the numerous underappreciated issues associated with hearing loss. Contact us online or by phone today to schedule an appointment with us, to undergo a screening for central hearing loss, and to take advantage of our services and resources!