Prevention, causes and consequences
Noise-related hearing loss is not only common, it is also incredibly easy to be exposed to: the ear's comfort range of noises are at around 60 dB, up 85 dB. Experiencing anything above that for a long period of time will definitely result in hearing impairment and eventual loss.
Noise-related hearing loss is also known as sensorineural hearing loss and is the most common type of hearing impairment. It occurs in those who have an affected cochlea or a lesion on the cochlear nerve. The cochlea sits very deep inside the inner ear and has microscopic hairs responsible for sensing waves of movement that we register as sound.
Damage to these delicate hair-like structures from frequent loud noises means the hair in the cochlea doesn’t register or generate their own sound in response to sensing sound. This type of abnormal response is what audiometry tests are usually for.
Noise is essentially high-frequency vibration that the inner ear is not accustomed to or designed to process. This can cause immediate damage to inner ear hair cells. The destruction of these tiny hair cells is terminal, meaning they cannot regenerate leading to progressive loss that will eventually become permanent.
Yet, damage to the middle ear and even the inner ear can be preventable or – in cases of tinnitus – reversible. For example, temporary hearing loss due to noise may feel like a dull ache, ringing or even vertigo. These are all the body's first line of defense, indicating something is awry – but not yet completely lost.
Causes of NIHL
There are a couple of causes of noise-related hearing loss. These are, of course, all variables of the noise itself.
- the intensity of sound (measured in dB)
- the frequency of sound (measured in Hz)
- the duration of sound (is it loud and constant? Is it a one-time loud bang? Was the person close to where the sound happened?
- the proximity to the origin of the sound (the closer to the point of origin, the more potent the aggressive vibration upon the delicate inner ear hair cells)
We live on a "noisy planet" and it's not just urban cities and metropolises: depending on your profession, even rural dwellings can be the source of loud noises. How? Farmers, carpenters, and smithies are all prone to noise-related hearing loss because of their everyday tasks.
What it comes down to, then, is whether we experience situations in which these loud noises are part of the everyday lives we lead. Are the noises, therefore, "occupational" or "non-occupational"?
Because work constitutes so much of our life, do we expect these loud noises to occur for a long time? Or are they occasionally encountered during recreational activities such as concerts or fireworks festivals?
Facing the Consequences of Hearing Loss
Hearing loss has very obvious impact on our quality of life and the kind of connection we build with those around us. It is, after all, one important part in the two-way mode of communication: listening and responding, which calls on hearing and speech.
Impairment leading to permanent loss can therefore affect how we communicate with others, how we express ourselves, and whether we feel isolated or understood by our friends and family.
But hearing loss has other, less obvious and yet more dangerous consequences. Over time, the quality of life of an individual with a hearing impairment degenerates to the point of affecting physiology. For example, tinnitus or constant ringing and earaches could increase anxiety and irritability, which causes a direct increase in heart rate and blood pressure.
Anxiety and stress on the lymphatic system as well as the gastrointestinal system is well catalogued. Gut bacteria are important in maintaining the digestive system's pH balance and ensuring digestion occurs properly. An increase in stomach acid due to anxiety could cause adverse effects on these friendly bacteria.
Effects of hearing impairment are far reaching, rather like a tree with offshoots and tendrils. It may not look directly related, but hearing loss is a definite cause for concern in these big and small ways.