Types of Hearing loss

Some children are born deaf (congenital deafness), and other children may become deaf (acquired) later in life, for example as a result of an illness.

• The two main types of deafness are conductive and sensori-neural. Some children can have a mixed hearing loss which is a combination of both conductive and sensori-neural deafness.

Conductive deafness is the most common type of deafness. It occurs when sounds cannot pass through the outer and middle ear to the cochlea and auditory nerve in the inner ear. This is often caused by fluid building up in the middle ear (glue ear). Most conductive deafness is temporary but there is a chance that it can be permanent. (click for more information)

Glue ear can cause temporary deafness and can either clear up naturally after a short period of time, or it can develop into a long-term condition requiring surgical intervention, such as grommets, or wearing hearing aids. Grommets are tiny plastic tubes that are put in the eardrum. Grommets allow air to circulate and stop fluid building up. (click for more information)

Sensori-neural deafness is caused by a fault in the inner ear or auditory nerve. Most cases are because of loss of, or damage to, the hair cells in the cochlea that means that the cochlea is not processing the sound effectively. (click for more information)

Progressive Hearing Loss – is when a hearing loss (mild or otherwise) is already present, and becomes worse. Symptoms may indicate that a person’s hearing is deteriorating, and there are many risk factors and potential causes a few include having a family with a history of hearing loss, being born prematurely, or having physical malformations of the head or ears. If the mother gets certain infections while she is pregnant or while she is giving birth, that too can result in a progressive hearing loss.

Unilateral Deafness – Unilateral deafness is deafness that affects only one ear. It is often referred to as ‘one-sided hearing loss’. One ear has a normal level of hearing, and most children with unilateral deafness manage very well in most situations. There are a few situations where they may find it more difficult to hear well.

Most children with unilateral deafness develop clear speech. Your child will hear well in most situations, but they may have difficulty:

• hearing sounds or speech on the side with the deafness;

• identifying the source of a sound or the direction a sound is coming from; and

• understanding speech when there is background noise.

Auditory Neuropathy – Auditory neuropathy and auditory dys-synchrony are terms used to describe a particular type of hearing problem when sounds may be transmitted normally through the middle ear and the cochlea but then do not transmit normally from the cochlea, or along the auditory nerve. This means that the child may be hearing something, but this is probably very distorted.

In this factsheet we use the term auditory neuropathy to refer to both that condition and auditory dys-synchrony.

Auditory neuropathy is sometimes abbreviated to AN. It should not be confused with other conditions of the ear and hearing which may also be abbreviated to AN (for example acoustic neuroma).

Is it a common problem?

The number of children affected by this condition is not yet fully known, but it is estimated that up to one in 10 profoundly deaf children have this condition.