We are forever exposed to sound in our environment such as the sound of the television, traffic, radio, household and much more. Usually, these sounds are at safe volumes and do not cause any damage to our ears. But, when we are exposed to harmful levels of sound that is commonly referred to as noise that is too loud, the sensitive parts of our inner ear run the risk of permanent damage in the form of noise-induced hearing loss.
To know how noise causes damage to one’s hearing ability, we must understand how we hear in the first place. Hearing depends on a complex process that transforms sound waves into electrical signals that the auditory nerves carry to the brain via a series of stages. They are as follows:
• The sound waves enter the outer part of the ear and go in through the narrow passageway that is called the ear canal. The ear canal takes the sound waves to the eardrum.
• When the sound waves hit the eardrum, it vibrates and sends them further inside to the three bones in the middle ear.
• The tiny bones in the middle ear coupe sound vibrations from the air to fluid vibrations in the cochlea of inner ear.
• Once the vibrations have caused the fluid present inside the cochlea to babble, the wave forms travel along basilar membrane (elastic partition that exists from the beginning to the end of the cochlea in the inner ear). These sound waves are ridden by hair cells that sit on the top of the basilar membrane.
• The sound waves transform into electrical signals and get carried to the brain by the auditory nerves. The brain translates these signals into sound that we recognise and make sense of.
Most causes of noise-induced hearing loss is caused by damage of death of the hair cells.
Noise-induced hearing loss can be caused by multiple factors such as:
• Surprising, one-time exposure to a harmful level of impulse sound such as that of an explosion
• Continuous exposure to loud sounds over a certain period of time such as noise that is generated in a wood workshop.
Sound is measured in the units of decibels. Experts say that sound that is less than 75 decibels does not cause any harm to the human ear even if it is exposed to this level for a prolonged period of time. But, if one exposes his/her ears to sound above 85 decibels, there may be a high risk of developing hearing loss. The louder the sound gets, the shorter time it takes for noise-induced hearing loss to develop.
To make sure that you are exposed to the right levels of sound, here is the average decibel rating for sounds that one is exposed to every day:
Noise generated by:
• refrigerator: 45 decibels
• normal conversation: 60 decibels
• motorcycle: 95 decibels
• mp3 player at maximum volume: 105 decibels
• firecrackers: 150 decibels.
There is no particular person who is at higher risk of developing hearing loss compared with the rest. People of all ages are at risk of developing hearing loss; this includes young adults, teens, children and older people.
Certain leisure activities that can put one at a high risk of developing hearing loss include shooting, hunting, listening to mp3 player at a high volume, snowmobile riding , attending loud concerts and playing in a band.
Read more articles on Understand Hearing Loss in Adults.