Causes

Generally, the causes of hearing loss symptoms are categorised by which part of the auditory system is not working or has been damaged. There are three types of hearing loss:

i. Conductive Hearing Loss (Outer / Middle Ear)

Conductive hearing loss occurs when there is a problem conducting sound waves through the outer ear, tympanic membrane or middle ear. Approximately 10% of all hearing losses are conductive, which can range from mild to moderate in severity. Conductive hearing loss can often be medically treated, and in many cases, hearing can be restored.

Possible causes can be:

• Temporary blockage ( e.g. accumulation of earwax, infection of the external ear canal ).
• Perforation of eardrum.
• Otitis Media (middle ear infection), where the middle ear becomes inflamed and filled with fluid, preventing the eardrum from vibrating. Most cases can be treated by antibiotics. In some cases, the insertion of ventilating tubes (grommets) may be necessary.
• Otosclerosis (stiff middle ear bones due to a build up of calcium around the stapes).

ii. Sensorineural Hearing Loss (Inner Ear):

Sensorineural hearing loss, also known as Nerve Deafness, occurs when the sensory hair cells in the cochlea or the auditory nerve are damaged. In some cases the problem lies in the central processing centres of the brain. As a rule, this damage cannot be reversed medically. Hearing aids are the recommended course of treatment.

Possible causes can be:

• Presbycusis (the aging process).
• Exposure to noise.
• Head injuries (trauma).
• Diseases (e.g. German measles during pregnancy, meningitis, Meniere's disease, Mumps, multiple sclerosis).
• Birth defect.
• Genetic disorder (inherited).

iii. Mixed Hearing Loss

Acoustic signals can be blocked in multiple places along its path. When a hearing loss occurs from conditions in the inner ear as well as the outer and/or middle ear, it is known as mixed hearing loss.

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