Having your ears checked
Your GP or practice nurse will first ask you or your child about any symptoms, including whether there is:
If you or your child has a hearing problem, your GP or practice nurse will do an ear examination. If they have concerns, they may refer you to an ear, nose and throat (ENT) specialist for further assessment.
Your ear will be examined using an instrument called an auriscope, which is sometimes also known as an otoscope. An auriscope is a small hand-held torch with a magnifying glass used to examine the eardrum and the passageway that leads to it from the outer ear.
An auriscope can be used to look for:
- discharge – fluid coming out of the ear
- a bulging eardrum – indicating that there is infected fluid in the middle ear
- a retracted eardrum – indicating uninfected fluid in the middle ear (glue ear)
- perforated eardrum – a hole in the eardrum, with or without signs of infection
- earwax or foreign bodies that might be blocking the ear
Childhood hearing tests
The various hearing tests that are carried out during infancy and childhood are outlined below.
Infant distraction test
In the past, the infant distraction test (IDT) was the main hearing test used by health visitors to test a baby’s hearing at the age of around eight months.
During the IDT, an examiner sits in front of the infant and uses a ball or a toy to gain their attention. A second examiner, sitting behind the infant then makes a noise at the infant’s ear level on either side. If the infant’s hearing is working normally, they should turn towards the sound.
Nowadays, the IDT is no longer used because it is unreliable and can only be used to make a diagnosis when a child is old enough to turn their head. Healthcare professionals realised that a more accurate hearing test was needed that could be carried out on newborn babies. This led to the Newborn Hearing Screening Programme being set up.
Newborn Hearing Screening Programme
Today, all newborn babies are tested as part of the Newborn Hearing Screening Programme (NHSP). The automated otoacoustic emission (AOAE) screening test is the hearing test that is used. The test is carried out by a trained hearing screener or health visitor (a qualified nurse who helps families with young children).
Automated otoacoustic emissions test
The AOAE test is a simple, painless test that produces immediate results and can be carried out while the baby is asleep. It involves placing a small probe into the baby’s ear which produces a gentle clicking sound. In normal hearing, some of the nerve endings in the cochlea (inner ear) automatically produce a noise of their own as a reflex when a sound is heard. This is often known as cochlear echo.
A cochlear echo will not be produced when the hearing is impaired. This makes the AOAE test a good hearing test. However, it is not totally reliable because sometimes no echo is produced even when a baby has normal hearing. Also, an echo may occasionally be produced when a baby’s hearing is impaired, and a baby who is born with normal hearing may go on to develop loss of hearing during their first year.
However, despite not being perfect, the AOAE test is much better than IDT screening, and nowadays far fewer children with hearing loss are diagnosed late (older than 12 months).
Before your baby has the AOAE test, the hearing screener or health visitor will explain the test to you. If the first test does not produce a clear result, your baby will be given a second test. However, an unclear test result does not necessarily mean that your child has a hearing impairment. It may be that conditions during the first test were not right, such as there being too much background noise.
Automated auditory brainstem response test
If two AOAE test results are unsatisfactory, an automated auditory brainstem response (AABR) test will be recommended for your child. In certain situations – for example, where a baby has spent a long period of time in a neonatal intensive care unit – they may be given an AABR test and an AOAE test as a matter of routine. The AABR test can be used to provide more information about the baby’s hearing.
An AABR test is usually carried out at home (if the baby is not in a care unit) and takes around 20 minutes to perform. Three sensors will be placed on your baby’s head and neck to detect how their ears, hearing nerves and brain respond to sound. Sounds will then be played through earphones and a computer will be used to record your baby’s responses. If their response is strong, it is unlikely that they have any hearing loss.
Like the AOAE test, the AABR test is not totally foolproof. If the result of the AABR test is satisfactory, your baby has good hearing and there is usually no need for further tests. However, an unsatisfactory AABR does not always mean that your baby has hearing loss, but that a further test is needed – an auditory brainstem response (ABR) test.
Auditory brainstem response test
After having an unsatisfactory AABR test, the next step is to carry out an auditory brainstem response (ABR) test. Unlike an AABR test, an ABR test is not an automated test. It is a much more sophisticated and accurate test that is carried out in a hospital audiology clinic by a highly trained audiologist (hearing specialist). The audiologist will also interpret the test results.
Like AABR, the ABR test uses headphones to produce sound and sensors are placed on the baby’s scalp and neck. The sensors pick up the electrical signals that are produced in the ears and hearing nerves and a computer turns these signals into a ‘wave’ that is displayed on a printout or screen.
As sounds become quieter, the waves get smaller and disappear completely when the hearing threshold is reached (when a sound is so quiet that you cannot hear it). Different types of ABR test can be performed to give information about the baby’s hearing at different sound frequencies and to determine whether a hearing loss is conductive or sensori-neural.
ABR tests are not used on every baby because they take about 45 minutes (and sometimes longer) to carry out. It therefore would not be practical to use the test for every baby, and the AOAE and AABR tests are used because they are simpler screening investigations, rather than in-depth examinations.
Again, even if an ABR test is unsatisfactory, it does not always mean that your baby has permanent hearing loss – for example, they may have a temporary blockage due to glue ear.
As well as the hearing tests described above, there are also a number of other tests that may be used at different stages of your child’s development. These are described below.
Visually reinforced audiometry
Visually reinforced audiometry (VRA) has replaced the infant distraction test (IDT) as the best way of checking a baby’s ability to react to the direction of sound.
During VRA, the baby sits on their parent’s lap and a tester stands in front to keep the baby’s attention. Another tester, positioned outside of the baby’s visual field, makes a number of different sounds. If the baby reacts by turning their head in the direction of the sound, they will be rewarded by seeing a small toy positioned at the side of the room, which either lights up or moves.
The reward is controlled by the testing audiologist and is only given to the baby if they turn their head in response to a sound. Nothing will happen if the baby turns to try to see the toy without a sound being made. Only rewarding the baby when they turn towards the sound reinforces their response and makes VRA a much more accurate test than the IDT.
Pure tone audiometry
Pure tone audiometry (PTA) tests the hearing of both ears and can usually be carried out when a child is over four years of age. PTA is the type of test carried out when a child starts school.
During PTA, a machine called an audiometer is used to produce sounds at various volumes and frequencies. The child being tested listens to the sounds through headphones and responds when they hear them by pressing a button.
In your child fails a pre-school audiogram, they may be referred to the ENT or audiology department of your local hospital for further testing.
Other childhood hearing tests
Other hearing tests that your child may have at the audiology department of your local hospital are briefly described below.
Play audiometry
Play audiometry involves your child listening to a sound and being asked to perform a simple task as part of a game to indicate that they have heard the sound. This is used for children who are too old for VRA but are not yet able to cope with a pure tone audiogram.
Speech perception test
The speech perception test, also sometimes known as a speech discrimination test or speech audiometry, involves testing your child’s ability to hear words without using any visual information. The words may be played through headphones or a speaker, or spoken by the tester.
Sometimes, the child is asked to listen to the speech sounds in the presence of a controlled level of background noise (speech in noise testing) – for example, to mimic the situation in a classroom.
Whispered voice test
The whispered voice test can be carried out on older children in a quiet room – for example, at a GP surgery. See adult hearing tests (box, left) for more information about how the test is performed.
Impedance tympanometry
The eardrum should ideally allow as much sound as possible to pass into the middle ear. If sound is reflected back from the eardrum, hearing will be impaired (or impeded). Fluid in the middle ear will impede sound. Impedance tympanometry measures the ‘impedance’ of sound by the eardrum.
During impedance tympanometry, a small tube will be placed at the entrance of your child’s ear and air will be gently blown down it into their ear. The test can be used to confirm whether your child has glue ear.
