The Remarkable Journey of Sound and Hearing Loss
Hearing is cool.
It adds dimension to our lives. It’s the source of much of the information we receive from outside sources – everything from hearing a seminar speaker to rolling thunder in the distance. (Time to take cover.)
Along with the other senses – sight, taste, touch and smell – our lives are richer, fuller and a lot more fun. But the thing is, we all (admit it) take healthy hearing for granted. When was the last time you had your hearing tested? When was the last time you wore hearing protection?
Yet, people with hearing loss also lose a certain level of quality in daily life. They miss the twittering birds or the soft whisper of a grandchild. There are numerous causes of hearing loss, and although hearing loss to some degree is inevitable with aging, there are some causes of hearing loss you can avoid with some basic information.
Let’s go back to Biology 101 for a quick tour of “The Remarkable Journey of Sound” and along the way, let’s look at some potential “bumps in the road” that can prevent that remarkable journey from taking place. The result? Hearing loss and even deafness.
It Starts With Sound Waves
We take hearing for granted, yet the process is complex and, indeed, quite remarkable when you break it down.
So, you’re watching the TV on the couch in the living room. Sound is coming at you from that 56-inch plasma shrine. Then, through that sound, in the distance, you hear your one-year-old crying down the hall. Let’s follow that baby’s cry.
When that child cries out, it creates a disturbance in the air. The disturbance is in the form of sound waves. Now, you don’t hear the baby’s cry the instant he lets loose. The sound waves travel through the air. They bounce off walls, even, maintaining the frequency created when the child began crying. But you still don’t know that a diaper change is in your near future.
The sound waves quickly reach you where they’re captured by the outer ear, which acts like a dish antenna. The pinna – that’s what the outer ear is called – gathers sound waves and shoots them down the ear canal.
First Bump in the Road: If the ear canal is blocked with wax, sound waves will be blocked in their journey of hearing. However, do NOT use cotton swabs to ream out the ear canal.
Ear wax, also known as cerumen, is natural and beneficial, capturing outside dirt and debris before they causes issues within your outer ear. If you do have an ear wax problem consider safe ear wax removal before digging in yourself. Your first option is to visit your physician or audiologist for ear wax removal. Second have your hearing tested by a certified professional to ensure the cleared ear wax was the source of your hearing loss as there may be an underlining hearing loss. Lastly purchase a wax softener to prevent wax build-up.
Warning: Don’t overdo it. It can cause dryness and lead to itchy ear syndrome. Remember, wax should be there so let your ears do their job and keep the cotton swabs in the medicine chest.
|Photo courtesy Sonic Innovations|
Sound Waves Are Converted To Electrical Impulses
Sound waves travel down the ear canal where they set in motion the ear drum, also called the tympanic membrane in the textbooks.
The ear drum vibrates and transfers this mechanical disturbance to the three smallest bones in the human body – the stirrup, the anvil and the mallet – named for their shapes.
Even as these three tiny bones are all a-tingle with the sound of the baby’s cry, you still haven’t heard the cries for a little dignity. Sound is still moving through the system as mechanical energy – sound wave vibrations hitting the ear drum and rattling three bones.
Second Bump In The Road: A damaged ear drum may lead to hearing loss, hearing distortion and a lot of frustration. Another good reason to keep things out of your ear canal. The ear drum is definitely reachable and, yes, you can puncture it practicing the traditional approach to ear hygiene.
Middle-ear fluid can also cause the eardrum to be less efficient at transmitting vibrations.
Next, consider the complexity of what’s going on. The ear drum vibrates. That vibration is transferred to three small bones – delicate bones. If these bones can no longer transmit vibrations from the ear drum, the hearing journey comes to an abrupt halt. Diseases such as otosclerosis can cause this to occur.
The vibrations created by the ear drum and passed along by the anvil, malleus and stirrup are next picked up by the cochlea – a small, fluid-filled organ deep in the ear. This is where things start to get interesting.
The cochlea picks up the vibrations, jiggling the fluid inside. The interior of the cochlea is lined with millions of hair-like projections that pick up the vibrations in the cochlear fluid. These projections have the ability to convert the vibrations passing through the cochlear fluid into electric impulses that are then sent to the hearing centers of the brain.
And get this: you still haven’t heard the baby’s cry, yet all of this activity takes place in the blink of an eye.
The brain receives sound information from the outside world in the form of electrical impulses along the auditory nerve.
Once they reach the hearing centers of the brain, the electrical impulses produced by the hairs lining the cochlea are processed. You now hear the sound and your brain sorts out a great deal of information instantly.
Your brain’s memory immediately recognizes the sound as your infant’s cry. Because those sound waves reach the right and left ears a split second apart, the brain is able to determine the direction or location of the sound – instantly.
Finally, the brain reacts and you react by getting up to handle another change of diapers.
Third Bump In The Road: The hearing mechanism can deliver the electrical signals to the brain but, as we age, or as the result of injury or head trauma, the hearing centers of the brain can be damaged and are no longer able to process sound.
In order to send these impulses to the brain, the hair cells within the cochlea must be properly functioning. Although we have millions, they are delicate and once they are gone, they are gone. Things that can cause hair-cell damage consist of excessive noise exposure (preventable), age, toxic drugs, various vascular diseases, smoking, and many other causes.
In addition to damaged hair-cells, the loss of cognitive function – the ability to interact with the outside world – is often an aspect of aging, disease and even lifestyle choices (not good ones, btw). Because of this our ability to process incoming sounds, especially speech in background noise, become more difficult with age.
Protect the Hearing You Have
Hearing loss is a fact of life with one-third of the over 65-crowd experiencing some degree of hearing loss.
In the U.S. alone, 28,000,000 people experience hearing loss – that’s almost one in 10 of us.
Anywhere along the journey sounds take can be damaged by illness, trauma, long-term exposure to loud noise (think workplace and MP3 players) and simple aging. The parts that make up the hearing and understanding system can wear out as time passes, which is why protecting your hearing today is so important.
Protect what you’ve got. Stay away from loud noise, wear ear plugs, ear cups, noise cancellation earphones or some kind of protection to prevent damaging all of that hearing apparatus you were born with.
The journey a sound takes is an amazing one, indeed. However, there are bumps in the road along the way. Regardless of your age or your degree of hearing loss, you’re the only one who can prevent things from getting worse.
If you’re 25 or 55, have your hearing tested regularly. The result will be a better listening experience, and a better living experience.