The external ear can be lost, but hearing is virtually unaffected. From the University of Iowa, one associate professor of audiology attests that prolonged exposure to noise causes inner ear damage, which negatively effects hearing. The Noise Technical Assistance Center through the US Environmental Protection Agency recently sponsored a noise symposium, at which the professor gave a talk.
The tiny hair cells, called cilia, of the inner ear are destroyed by noise, which results in hearing defects. Sound stimulates the cilia, which send corresponding electrical signals to the brain for interpretation. It is generally accepted that hearing loss arises as one ages. Premature hearing loss can happen, as with prolonged exposure to loud noise.
Cilia do not recover from any damage, unlike other cells. Hearing aids help in increasing the volume of sounds, but they do not help in sound differentiation. The first stage of hearing loss is loss in soft, high frequency sound. Later, the person feels isolated, as he can no longer participate in conversations, listen to TV or the radio, or talk on the phone.
It has been known for quite a time that noise causes hearing loss, but few know its other dangers to health. People should realize that noise makes illnesses worse, but does not actually cause them. Noise increases stress and insomnia, which are risk factors for hypertension and ulcers in themselves. With loud noise comes an adrenaline reaction, complete with elevated blood pressure, increased breathing rate, and muscle tightening.
Not until the noise subsides does the stress response subside. The stress response aggravates and causes conditions, such as stress, high blood pressure, cardiovascular disease, ulcers, headaches, asthma, and colitis. Sleep disruption due to noise is certainly well documented. You can find many who will give you such a testimonial. Sleep is disrupted in both depth and duration.
A lighter sleep state is the result of noise, though it may not result in complete wakefulness. Sleepiness and inefficiency are the first effects of less sleep, which eventually results in health problems. Emotions and behavior are manipulated by noise, resulting in such actions as anti-social behavior, suicide, and murder. When people call for help, they may not be heard due to the noise.
With ear protection devices, one has a cushion against loud, prolonged noise. Ear plugs and muffs give the most protection. Neither is better than the other. However, ear protection does not afford miracles. Loud sound can go straight through the skull to rattle the inner ear.
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