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Main types of hearing loss
Noise and the ageing process are two causes of inner ear hearing loss.
As we grow older, many of us experience a decline in our hearing. Although the degree of disability varies greatly, and some people adjust quite well to the slow decline in their hearing, for many this form of hearing loss, known as presbyacusis, causes frustration, loneliness and depression.
Sound reaches our ears as vibrations which are channelled along the ear canal to the eardrum. When the eardrum vibrates, it causes the three little bones of the middle ear to rock back and forth and they in turn pass the vibrations into the inner ear (or cochlea) where they are detected by special cells known as sensory 'hair' cells. Hairs on the tips of these cells detect the vibrations, enabling the cells to transmit signals to the brain.
As we grow older, hair cells will naturally die off, coinciding with a deterioration in our hearing. However, exposure to excessive noise can distort and damage hair cells, making them unable to transmit incoming sound to the brain and resulting in permanent hearing impairment.
