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Hearing and Deafness

Hearing loss can affect any age and statistically one in six adults have some degree of hearing loss. This increases to three in four in old age. Children can also be affected, although this is usually due to fluid in the middle ear or to chronic infection. In some cases, a child is born with a hearing loss either due to genetic factors or other congenital factors.

The mechanism of hearing

Sound waves are conducted along the ear canal where they set the eardrum into vibration which in turn are conveyed by three small ossicles (small bones in the ear) to the the inner ear or cochlea where the sound waves are changed into electrical signals which are passed on to the brain along the nerve for hearing.

Types of deafness

The causes of deafness can be generally distinguished into two types , the conductive hearing losses where the problem lies in the ear canal or the middle ear, and the sensori-neural hearing losses, where the problem lies in the inner ear and fails to translate the sound waves into an electrical signal (sensory) or get conveyed to the brain because the nerve is non functioning (neural).

A conductive hearing loss for example may be due to wax blocking the ear canal, or infection, a collection of fluid, trauma or fixation or loss of the ossicles in the middle ear. This type of hearing loss can be corrected frequently by surgery or medication.

A sensorineural hearing loss where the problem is in the inner ear or on the nerve that conveys the signal to the brain is frequently not treatable and is usually managed by hearing aids if the hearing needs to be amplified. There are many causes, the commonest being that of hearing loss in old age (presbyacusis), but other causes include noise exposure, infections, trauma, drugs and very rarely it may be due to a growth or tumour in the brain.

An ENT specialist may be required:

-If there is a sudden hearing loss (within 1-2 days), treatment should be started as soon as possible after its onset.
-A hearing loss is felt more so in one ear only.
-If there is a slow and gradual worsening of ones hearing.

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