Understanding childhood deafness

A family play together in a sand pit in the garden.

What is deafness?

We use the term ‘deaf’ to refer to all levels of hearing loss in children, including a partial or total loss of hearing. This includes those who may describe themselves as having a ‘hearing loss’, ‘hearing impairment’ or as ‘deaf’, and includes children who have glue ear.

Deafness, or hearing loss, happens when one or more parts of the ear are not working effectively. To understand this, it’s useful to know how the ear works.


The ear and how it works

 The ear has two main functions.

  • It receives sound and converts it into signals that the brain can understand.
  • It helps us to balance.

The two functions are closely related.

A diagram showing the workings of the inner ear

Click here to view large version of image

The ear is the first part of the hearing system. The pinna (the outside part of the ear) catches sound waves and directs them down the ear canal. The waves then cause the eardrum to vibrate. These vibrations are passed across the middle ear by three tiny bones: the malleus, incus and stapes (sometimes known as the hammer, anvil and stirrup, known together as the ossicles). The bones increase the strength of the vibrations before they pass through the oval window into the cochlea.

The cochlear looks like a snail’s shell. It is filled with fluid and contains thousands of tiny sound-sensitive cells. These cells are known as hair cells. The vibrations entering the cochlea cause the fluid and hair cells to move, much like the movement of seaweed on the seabed when waves pass over it.

As the hair cells move, they create a small electrical charge or signal. The auditory nerve carries these signals to the brain where they are understood as sound.

For an ear to work fully and allow us to pick up sound, all of these parts must work well.


Does my child have a hearing loss?

If you are concerned about your child’s hearing, we advise that you speak to your GP in the first instance. However, you may find this early years app, which enables you to test your child’s hearing in your own home, useful.


What does having a hearing loss sound like?

Although it's not possible to exactly replicate a child's deafness, there are websites that use computer software to simulate average hearing levels.

Find out more information on:


Types of deafness

There are two main types of deafness.

  • Sensorineural deafness, or nerve deafness as it is sometimes called, is a hearing loss in the inner ear. This usually means that the cochlea in the inner ear is not working effectively. Sensorineural deafness is permanent.
  • Conductive deafness means that sound cannot pass efficiently through the outer and middle ear into the inner ear. This is often caused by blockages such as wax in the outer ear, or fluid in the middle ear (glue ear). Glue ear is a very common condition, especially in pre-school children.

It is possible for children to have a combination of sensorineural and conductive deafness. This is known as mixed deafness. One example of mixed deafness is when someone has glue ear as well as permanent sensorineural deafness. It is also possible to have a permanent conductive deafness, but this is less common.
Very few deaf children have no useful hearing. Most deaf children can hear some sounds at certain frequencies and loudness, and with the use of hearing aids they are often able to hear more sounds.

Click here for further information on Glue ear.


Unilateral deafness

Deafness in one ear only is known as unilateral deafness. Unilateral deafness is also referred to as one-sided hearing loss or single-sided deafness (SSD).

Our webpage on unilateral Deafness explains the major impacts it can have on children and provides helpful information on how you can manage them.


Levels of deafness

The level of your child’s deafness can be described as:

  • decibel (dB) hearing level, or
  • ‘mild’, ‘moderate’, ‘severe’ or ‘profound’.

Below are the terms used to describe levels of deafness and the decibel hearing levels they refer to.

Level of deafness
 Hearing level in decibels (dB)
 Mild 21–40
 Moderate 41–70
 Severe 71–95
 Profound 95+

Your child’s audiologist will be able to give you more information about the level of your child’s deafness. They will also be able to explain the sounds that your child can and cannot hear.


Why does my child have a hearing loss?

A Mum cuddles her baby girl

There are many reasons why a child can be born deaf or become deaf in childhood. It is not always possible to identify the reason, but you may be offered further tests to try to establish the cause of your child’s deafness.

Causes before birth (pre-natal causes)

Around half the deaf children born in the UK every year are deaf because of a genetic (inherited) reason. Deafness can be passed down in families, even though there appears to be no family history of deafness. For about 70% of these deaf children, no other problems will occur. For the other 30%, the gene involved may cause other disabilities or health problems.

Deafness can also be caused by complications during pregnancy. Infections such as rubella, cytomegalovirus (CMV), toxoplasmosis and herpes can cause a child to be born deaf. There are also a range of medicines, known as ototoxic drugs, which can damage a baby’s hearing system before birth.

Causes in early childhood (post-natal causes)

Being born prematurely can increase the risk of a child being deaf or becoming deaf. Premature babies are often more prone to infections that can cause deafness. Severe jaundice or a lack of oxygen at some point can also cause deafness. Infections during early childhood, such as meningitis, measles and mumps, can be responsible for a child becoming deaf.

Occasionally, a head injury or exposure to loud noise can damage the hearing system.

Medical tests used to help diagnose the cause of permanent deafness

Information about how you can try to find out the cause of your child’s hearing loss can be found in Chapter 8 ‘Medical tests used to help diagnose the cause of permanent deafness’ in our publication Understanding Your Child's Hearing Tests.

Genetic counselling

This resource is written for anyone from a family where one or more family members (including children) are deaf.

Download: Genetic Counselling, Information for Families

Click here for more information on Causes of deafness.

Click here for more information on Genetic conditions associated with hearing loss.


Finding reliable health information online

As you turn to the internet to research childhood deafness, you’ll soon discover that there is an enormous amount of health information online. It can be overwhelming and difficult to know what information is useful, up to date and accurate.

Click here for guidance from the NHS on how to find reliable health information online.

Other useful websites










Got a question about deafness? Have a look at our Parents' FAQs.