Potential causes of hearing impairment
Most people suffer some hearing impairment, as they get older. Being in a noisy environment can make hearing loss greater. Noise above 50 decibels has been shown to reduce the comfort and efficiency of people at work and at home. Higher levels are thought to partly contribute to high blood pressure, nervousness and mental illness. Chronic exposure to sound of 90 decibels or more can cause permanent damage.
Causes of deafness
Impaired hearing or deafness can be a result of:
Damage to the eardrum (caused by infection, a mechanical blow or a very loud noise)
Damage to any of the three ossicles in the middle ear (due to a birth defect or mechanical damage)
Build up of fluid in the middle ear (due to a respiratory tract infection)
Damage to the sensory cells lining the cochlea (which may be caused by loud noises)
Damage to the auditory nerve (birth defect associated with rubella)
Exposure to loud sounds may cause temporary damage to the cilia lining the cochlea
Industrial deafness
Exposure to continuous loud sounds causes permanent hearing damage. The OHS (noise) regulation 1996 defines a workplace as unsafe and a risk to health if any person is exposed to noise levels that exceed 85dB for 8 hours or peak at more than 140dB. Exposure to noise levels above these values can result in hearing loss, which is described as industrial deafness. Once hearing loss occurs, it cannot be reversed.
Repeated exposure to loud sounds (single exposure such as an explosion) can damage the organ of Corti (contains the auditory receptor cells) in the cochlea. These cells are not replaced.
Preventing noise-induced hearing loss:
When you know you will be exposed to loud noises, either...