Services

HOW THE EAR WORKS

The human ear receives and transmits sound waves to the brain where they are analyzed and interpreted. Perhaps the best way to describe the function of the ear is to describe the pathway sound takes through the different parts of the ear.

1 - THE OUTER EAR

     Collects sound waves and directs them into the ear canal where they are amplified by its funnel-like shape and channeled on to the      eardrum.

2 - THE MIDDLE EAR

The middle ear is an air-filled chamber connected to the nasal and throat passages by the eustachian tube, the purpose of which is to equalize the air pressure on both sides of the eardrum. The eustachian tube is usually closed but is opened naturally when you swallow or yawn.
On reaching the eardrum, the sound waves cause the eardrum to vibrate, transmitting the sound to the delicate bones of the ossicular chain. These tiny articulated bones - commonly referred to as the 'hammer, anvil and stirrup' - mechanically connect the eardrum to the oval window of the inner ear. The movement of this oval window transmits the pressure waves of sound into the inner ear.

3 - THE INNER EAR

The fluid-filled inner ear consists of the spiral-  shaped cochlea (an ancient Greek word for the shell of a snail). The passageways of the cochlea are lined with about 20,000 microscopic hair cells that convert sound vibrations   into nerve impulses which are then sent to the brain. Here, these impulses are interpreted as meaningful sounds.

In 90% of cases, a hearing loss occurs because the delicate hair cells in the inner ear either break or weaken - typically because of aging or exposure to loud noises. This is called a sensorineural (or 'perceptive') hearing loss.

The effects are almost always the same - it becomes harder to distinguish speech from noise, certain high-pitched sounds such as birdsong disappear altogether, people seem to be mumbling and you often have to ask them to repeat themselves.

The problem is that the brain doesn't receive all the sounds and frequencies it needs to make, for example, speech understandable. It's a little bit like removing all the high keys on a piano and asking somebody to play a well-known melody. Even with only 6 or 7 keys missing, the melody might be difficult to recognize and wouldn't sound right at all.

Once the hair cells in the inner ear are damaged, nothing can be done to repair them. A hearing instrument can, however, greatly improve your hearing ability. You can also help to prevent further deterioration to your existing hearing by avoiding over-exposure to loud noise.

The most common types of hearing loss are:

Conductive Hearing Loss.

This type of hearing loss involves an obstruction to sound waves reaching the inner ear. It can be caused by accumulation
of wax in the ear canal, perforation of the eardrum, fluid in the middle ear or abnormal bone growth in the middle ear
(otosclerosis). Often, a conductive loss is responsive to medical or surgical treatment.

Sensorineural loss

is the most common type of hearing loss, occurs when the nerve endings in the inner ear are not transmitting sound properly, often as a result of damage to the hair cells in the cochlea. This damage can by caused by a number of things, including noise, or a natural withering of the cells (presbyacusis) that comes with age. Sensorineural loss cannot be cured medically, but it can usually be improved through the use of hearing instruments

Tinnitus.

Some people with sensorineural hearing loss also notice a constant ringing or rushing sound in their ears. This is called tinnitus.
It is often permanent and not medically or surgically treatable.