Hearing Loss: Condition or Symptom?
Did you know that hearing loss isn’t always a standalone condition? In fact, sometimes hearing loss is a symptom of disease! And most often, hearing loss is associated with diseases of the cardiovascular system or cognitive decline. These connections have been made by various studies led by researchers around the world, and the ties they’ve made are crucial for everyone to know and understand. Some of the most definitive links between hearing loss as a symptom of specific diseases include obesity, Parkinson’s Disease and even Dementia. Here are the surprising ties:
Obesity and Hearing Loss
Obesity is a condition characterized by the excessive accumulation and storage of fat in the body. According to the Centers for Disease Control and Prevention, more than one-third (36.5%) of US adults have obesity. Most commonly, obesity-related conditions include heart disease, stroke, type 2 diabetes and certain types of cancer — but obesity also contributes to hearing loss. Here’s the connection: Studies have shown that active blood flow and oxygen significantly aid in healthy auditory systems. Since obesity puts a massive strain on the walls of our capillaries (blood vessels or veins) it is harder for them to transport oxygen to the tiny hair cells which are responsible for detecting sound, and translating these sounds to our brains for interpretation. And because obesity can also cause high blood pressure (which also increases your risk of developing hearing loss), your chances of developing a sensitivity to noise, Tinnitus and even noise-induced hearing loss significantly increase.
Parkinson’s Disease and Hearing Loss
As a chronic and progressive movement disorder, Parkinson’s Disease is identified through tremors of the hands, arms, legs, jaw and face, slow movements, rigid or stiff limbs and impaired balance or coordination. Individuals suffering from this disease also experience an increase in certain chemicals known to affect the inner ear function. This correlation drove Italian researchers at the University of Naples Parthenope to conduct a study which screened and compared hundreds of patients with Parkinson’s to another group of similar age and sex without the disease. These researchers found that almost 90% of the patients with Parkinson’s disease exhibited age-related hearing loss in one or both ears — a significant number more than their healthy counterparts, and a finding that led to an interesting conclusion: The increase in chemicals found in Parkinson’s disease affects inner-ear susceptibility to noise-induced or age-related hearing loss.
In a different study in Taiwan (Lai et. al, 2014) researchers took a look at how the lack of dopamine — a neurotransmitter responsible for how our central nervous system functions, and a key determining factor in those with Parkinson’s — affects the ability to hear. After comparing the results of thousands of individuals observed in the study, researchers found that patients with hearing loss were 1.5 times more likely to have Parkinson’s as compared to a control group without hearing loss. Why? Because dopamine helps to protect the cochlea from noise exposure. So, its absence leaves the inner ear vulnerable to noise-induced hearing loss.
Dementia and Hearing Loss
The Hearing Loss Association of America has stated that hearing loss may increase the risk of dementia. Ask any hearing care professional the effects hearing loss has on our cognitive functioning, and all of them will tell you that they are significant (just think about how exhausting it can be just to understand what you’re hearing!). “The general perception is that hearing loss is a relatively inconsequential part of aging,” Frank Lin (otologist and epidemiologist at Johns Hopkins University) told AARP, “but recent studies suggest that it may play a much more important role in brain health than we’ve previously thought.”
In fact, JAMA Otolaryngology — Head & Neck Surgery recently published a study (Association of Age-Related Hearing Loss With Cognitive Function, Cognitive Impairment, and Dementia, Dec. 7, 2017) revealing striking results from a systematic review and meta-analysis of 40 studies from 12 countries which included 20,264 unique participants. The findings? A relationship between age-related hearing loss (ARHL) across all domains of cognitive function: “Among cross-sectional studies, a significant association was found for cognitive impairment and dementia.”
Does this mean having ARHL means you will develop dementia? Not necessarily. However, it does suggest that ARHL is a possible biomarker (in other words, a measurable indicator of a biological condition) and a modifiable risk factor (meaning you can take measures to decrease your risk of developing a disease) for cognitive decline, cognitive impairment and dementia. But as the JAMA study states, additional research is still being conducted to further examine and understand causes and treatment underlying this relationship.
Like most medical conditions, the sooner you seek treatment from a medical professional — for hearing loss or any other symptom or condition — the better. So, if you or someone you know is currently experiencing or displaying symptoms of hearing loss, get to know the resources that can get you started on your journey not only towards better hearing health, but also how hearing instruments can significantly enhance your life. Find a hearing care center near you to begin.