In modern society, we are constantly surrounded by background noise in our day to day lives. Background noise is the description given to any unwanted environmental sound or any general unspecified sounds. This noise can be described subjectively in terms of its pitch (frequency) and loudness (intensity). Excessive long term exposure to noise can have a detrimental effect on hearing.
The cochlea is the auditory portion of the inner ear and has two types of hair cells which both have different functions that let us hear. Generally the outer hair cells receive information from the brain and the inner hair cells send information to the brain. The basal hair cells respond best to high frequency sound and the apical end better to low frequencies. It is largely due to the degeneration of these hairs cells that an individual suffers from a hearing loss. Loss caused by damage to the hair cells is described as sensorineural hearing loss.
Noise Induced Hearing Loss is caused by damage to the hair cells of the hearing organ (cochlea) caused by exposure to higher than normal levels of noise. This occurs due to force of impact on the hair cells when the noise occurs, which may cause temporary or permanent damage. Noise-induced hearing loss is the second most common form of hearing loss, after Presbyacusis or age related loss.
Typically noise induced hearing loss occurs in both ears, between 3,000 and 6,000 Hertz (Hz) and develops gradually over time. All sounds entering the cochlea do so at the basal end and travel towards the apical end, therefore the hair cells at the basal end are subjected to more wear resulting in them degenerating at a quicker rate.
The extent of the damage and speed of onset of the hearing loss caused by noise is dependent on a number of factors including; length of exposure, loudness and proximity to sound and whether or not any form of hearing protection is worn.
Hearing protection is available from many resources and comes in many varieties. The cost of the protection largely determines the level of protection it provides. They work to protect the nerve damage by dampening the loudness of the noise. The types of Hearing Protection available on the market include the following:-