The Causes of Acquired Hearing Loss

When it comes to hearing loss, the names of the game are treatment and prevention. Some of us are born with hearing loss, and in these cases treatment is the only option, but for the rest of us, prevention is really important to make sure we have the best hearing we can throughout our lives.

The broad categories of hearing loss are sensorineural, conductive, and mixed. Sensorineural hearing loss accounts for 90% of the hearing loss in the world, and it’s the kind that results from damage to the tiny, hair-like cells in the inner ear, called stereocilia. Most cells in the body are born, die, and are replaced on a regular basis, but when it comes to the stereocilia, the ones we’re born with are the only ones we’ll ever have.

Stereocilia can be damaged by exposure to loud noise, physical trauma, and other medical conditions. They also tend to stop working as we get older. In fact, the description of “normal” hearing changes through the human lifespan. Normal hearing for a 20-year-old involves a lot more high-frequencies than normal hearing for a 40-year-old.

And while one-third of those aged 60–69 have hearing loss, two-thirds of those over age 70 have it. Nearly 100% of centenarians have hearing loss, suggesting that we’re all likely to experience it if we just live long enough!

Let’s talk about some of the causes of acquired hearing loss:

Loud Noise

Noise is a major cause of hearing loss today. Our world just seems to keep getting louder. While noise-induced hearing loss (NIHL) was on the decline around the turn of the millennium, it’s back in a big way today. About 10% of millennials have hearing loss, while already 17% of Gen-Z’ers have it. Especially considering that Gen-Z is the younger of the two generations, this spike is pretty alarming!

Lots of people think that sound has to be painful to cause NIHL, but this isn’t true. In fact, sound levels as low as 85 dBA (decibels A-weighted)—about the level of a gas-powered lawnmower—can cause permanent hearing loss after about 8 hours of exposure. For every additional 3 dBA in level, the safe time of exposure is cut in half. By the time we reach 100 dBA—the average volume of a high school dance—permanent hearing loss occurs after only 15 minutes of exposure.

If you spend time around loud noise, the solution is pretty simple—just wear hearing protection! Earmuffs are a good choice for many activities, and it’s always a good idea to carry a set of earplugs with you. There’s a wide range of quality and specifications when it comes to earplugs, so give us a call if you have questions about the best option for yourself.

Physical Trauma

Car accidents, sports injuries, and other head injuries can cause hearing loss. “Physical trauma” also includes catastrophically loud sounds, like a bomb going off nearby. These kinds of explosions can cause immediate hearing loss.

Repeated, low-level physical traumas, like those experienced by American football players, can lead to something called “hidden hearing loss.”

Under normal circumstances, the electrical impulses that carry sonic information travel from our ears to the auditory cortex of our brains via the auditory nerves. Nerves are surrounded by a fatty substance called “myelin,” which functions like the rubber jacket around an electric cord. It keeps the information that the nerve is sending on that nerve. When the sheath is damaged, information can leak, and that’s what happens with hidden hearing loss.

In the context of a pure-tone hearing test, someone with hidden hearing loss will appear to have normal hearing. This is because the leaky auditory nerves are only transferring one sound at a time. When the same person goes out to a restaurant, the chaotic sonic environment will become difficult to comprehend, as a lot of the information coming into their ears will never make it to their brain.

Medical Conditions

Our hearing ability can indeed be like the “canary in the coal mine” of our bodies. When we have chronic inflammation, the restricted blood flow will eventually cause hearing loss. Underlying issues like hypertension, cardiovascular disease, diabetes, some viral infections, and obesity can all cause hearing loss.

An underlying cardiovascular condition can cause age-related hearing loss (presbycusis) to progress much faster than normal. By getting a regular hearing test, this might be discovered and result in a life-saving intervention!

If you or a loved one may be experiencing hearing loss, make an appointment for a hearing test today! Hearing aids are better than ever, and are still the best treatment for most sensorineural hearing loss!