Hearing Loss

How We Hear

The ear is divided into three sections; the outer ear, the middle ear, and the inner ear (see diagram).

1. The outer ear consists of the pinna, ear canal and eardrum. Sound is collected by the pinna and directed into the ear canal and down to the eardrum.

2. The middle ear consists of an air filled cavity containing the three linked bones. Sounds are transmitted via vibration of the eardrum, through the chain of bones and on to the inner ear. This cavity is connected to the back of the nose by the Eustachian tube, which allows air in and out of the middle ear space to equalise pressure.

3. The inner ear consists of the cochlea and semicircular canals. The cochlea is a shell shaped bony spiral that contains tiny hair cells and nerve-endings. These hair cells and nerve endings detect sound and convert this information into nerve impulses that are directed to the brain. The semicircular canals are part of our balance organs.

Types of Hearing Loss

Type of Hearing Loss Conductive Sensorineural
Problem Area Outer or Middle ear (eardrum, middle ear bones) Inner ear (cochlea, auditory nerve)
Causes Wax blocking the ear canal, perforation of the eardrum, damage to the middle ear bones, middle ear fluid (glue ear) Exposure to loud sounds, genetic disorders, natural ageing process, certain viral illnesses, accidental trauma to the ear
Level of Loss Mild to moderate and often treatable Mild to profound and often permanent
Treatment Hearing aids, medical or surgical intervention Hearing aids or cochlear implants