Hearing Loss

How is sound detected?

In a normal ear sound travels down the ear canal and causes movement of the ear drum. This inturn causes movement of the three little bones (ossicles) in the middle ear. The middle ear usually is filled with air. Movement of the bones in the middle ear inturn cause movement of fluid in the inner ear (cochlea), and this sends signals to the brain down the hearing (auditory) nerve. In the brain the signals from the nerve are processed into recognisable sounds.

What causes hearing loss?

Any disruption of the above mechanisms may give rise to hearing loss, the mechanisms that may cause hearing loss include:

1)Blockage of sound travelling down the ear canal e.g impacted wax,or infected ear canal

2)Impaired movement of the ear drum, this may arise if the ear drum is scarred and stiff, or is deficient i.e has a large hole within it.

3)Impaired movement of the bones in the middle ear, this may arise if

i)one or part of the bone is missing

ii)part of the bony lever mechanism is stiff

iii)the middle ear is not filled with air, it may for example be filled with fluid e.g in glue ear, pus e.g in middle ear infection, or blood after trauma

4)Abnormalities of the inner ear e.g hearing loss of old age (presbyacusis), noise trauma, or Merniere’s disease

5)Abnormalities of the hearing (auditory) nerve or brain processing pathways e.g aging, brain injury, stroke

What should I do if I have a hearing loss?

The first step is to seek medical help to acertain the cause of your hearing loss. The doctor will take a history and examine you, and will arrange for you to have a hearing test. Having made a diagnosis he will be able to advise you as to what the management options may be.

What are the treatment options?

Amplification of sound (hearing aid)

A hearing aid acts by amplifying the sound at appropriate frequencies. A hearing aid may be a suitable option for managing all types of hearing loss. It is often the only option in inner ear, or auditory nerve deafness. Digital hearing aids are now available through the NHS.

Medical treatment or surgery

Hearing loss due to deficiencies or problems within the ear canal, ear drum or middle ear may be improved by medical therapy, surgical therapy, or a hearing aid. The treatment options depend on the exact cause of the hearing loss. Your doctor will be able to discuss with you the treatment options once an accurate diagnosis has been reached.