Protect Your Hearing!
“More than 120 million people in the world have a disabling hearing impairment.” —World Health Organization.
We must protect our hearing. As we get older, however, our hearing slowly but continually worsens. Society, with all the varied sounds and noises that are generated, seems to have sped up this process. A senior scientist at the Central Institute for the Deaf, in St. Louis, Missouri, U.S.A., had this to say: “About 75 percent of the hearing loss in the typical American is caused not by the aging process alone but by what you’ve done to your ears throughout your lifetime.”
While it is true, intense, brief exposure to loud sounds can be harmful to the sensitive structures in your ear. However, it is more often that hearing loss is a result of “the cumulative effect of noisy jobs, noisy hobbies, noisy recreational activities,” said hearing specialist Dr. Margaret Cheesman. So is there anything we can do to protect our hearing? To find the answer, we first should know something about our sense of hearing.
The Sounds We Hear
There is no question our environment is getting louder all the time. Every day we are battered by sounds of varying intensities ranging from car and road noises, buses, and trucks in the streets to the loud noises of power tools and equipment in the workplace.
Often times we make the problem worse by turning up the volume. The most popular way of listening to music these days is through the use of earbuds. According to Marshall Chasin, co-founder of the Musicians’ Clinics of Canada, surveys conducted in Canada and in the United States indicate that youths are increasingly suffering a loss of hearing caused by the use of headphones with the volume turned up.
So how loud is too loud? We characterize sound in three different ways —by duration, by frequency, and by amplitude. Duration is the easiest as it simply refers to the length of time a sound is heard. A sound’s pitch, or frequency, is described in cycles per second, or hertz. The range for normal, healthy hearing is from about 20 to 20,000 Hertz.
Volume
A sound’s amplitude, or volume, is looked at in a unit of measurement called decibels (dB). According to the W.H.O normal conversation has a sound level of roughly 60 decibels. Audiologists note that the longer we are exposed to any noise louder than 85 decibels, the greater the eventual hearing loss will be. The louder that sound is, the faster the damage to your hearing will be. A Newsweek magazine report stated: “Your ear can safely handle two hours with a power drill (100 dB), but not more than 30 minutes in a noisy video arcade (110 dB). Every 10-decibel increase on the sound scale represents 10 times more ear-battering noise.” Tests confirm that sound becomes painful at approximately 120 decibels. But did you know, some home stereo equipment can produce sound at more than 140 decibels!
To better understand why loud sounds damage your hearing, we must first know what happens when sound waves reach your ears.
How Our Hearing Functions
The shape of the outer ear, the part that gives us each our own unique look, called the auricle, or pinna, is designed to collect sound waves and funnel them into the ear canal, where they eventually reach the eardrum. Once the sound wave hits the eardrum, it causes it to vibrate. The eardrum then causes the three bones in the middle ear to vibrate. Once this takes place the vibrations move to the inner ear, a fluid-filled sac encased in bone. Here the vibrations move through the fluid inside the cochlea. The cochlea, the snail-shaped hearing part of the inner ear that contains the hair cells. The fluid in the cochlea triggers the hair cells to produce readable nerve impulses. These responses are then sent to the brain, where they are decoded and interpreted as sound and speech.
The limbic system, the complex nervous system in your brain, helps the brain decide which sounds to pay attention to and which to dismiss. This is what allows a mother to not consciously hear the normal sounds of her child at play, but still respond instantly to a cry for help or alarm. Hearing with two ears allows us to hear in stereo, which is very important to us. Stereo hearing allows us to identify what direction the sounds are coming from. Yet, when a sound consists of speech, the brain is only able to understand one message at a time. “This is why,” according to the book The Senses, “when listening to someone while talking on the telephone, people cannot readily take in what the person next to them is saying.”
How Does Noise Damage Our Hearing
When visualizing how loud sounds can damage our hearing, consider the following analogy. One occupational safety report compares the hair membranes in the inner ear to wheat in a field. Then compares the sound entering the ear to the wind. A gentle breeze, like a low-level sound, will move the tops of the wheat, but the wheat is not damaged. Increased wind velocity, however, will increase the stress on the wheat stalk. A sudden, high, violent wind can immediately damage the stalks; Or continuous exposure to lower winds over a long period of time may damage the stalk beyond repair. Eventually causing it to die.
The delicate hair cells in our inner ear react very similarly to noise. An instant loud blast can damage the tissues of the inner ear and leave scar tissue in its place that causes permanent hearing loss. Prolonged exposure to dangerous noise levels can permanently damage the delicate hair cells in your cochlea. The hair cells are unable to regenerate once they are damaged. This is also the leading cause of a result known as tinnitus —a buzzing, ringing, or roaring in the ears or head.
Protect Your Hearing!
While no doubt or family history or some unforeseen events may result in damage to our hearing; There are precautions that we can take to ensure we are protecting and prolonging our sense of hearing. It is important to educate yourself in advance of the potential risks around you. As one audiologist said, “waiting for a problem to arise before taking action is like applying the suntan lotion after you’ve been burned.”
It doesn’t often matter what we are listening to so much as HOW we are listening. For example, while using stereo earbuds; You probably don’t want the volume to be so loud that it drowns out the sounds going on around you. If you are listening to music on your car stereo or on your home system and have the volume loud enough you can’t hear a regular conversation, this is a good indication your volume is loud enough to cause damage to your ears. Industry experts warn that two to three hours of exposure to 90 decibels can lead to damage. It is always recommended that you wear some form of hearing protection in noisy environments.
