"Audiometry involves the testing of hearing. There are various different ways to test hearing depending on the age of the person involved and the type of hearing loss."

What is Audiometry?

Audiometry is the medical word used to mean hearing tests. Audiometry checks whether there are problems with any of the different mechanisms that allow us to hear sound.

How does audiometry work?

There are various types of tests that can be carried out to check hearing ability. They vary according to who is being tested and why. Babies are obviously not able to say when they have heard a sound, so special methods are used. In children the principles of testing may be the same, but the way in which the tests are carried out may be varied to get the most accurate results. There are also additional tests which help to check how well the middle ear and the brain are working in the hearing pathway.

Testing in babies and young children

In young children a technique called visual reinforcement audiometry is used. In this test the child hears sounds, usually through speakers in the testing room. When the child hears the sound and turns their head towards it they are given a reward. Usually this is a visual reward such as the flashing lights of a toy. The person testing the child hearing continues reinforcing this behavior with a reward every time the child turns towards a sound. Then the person carrying out the test begins to assess the child hearing by seeing if they respond to different types of sound. By doing this it is possible to find the quietest sound the child can hear. Different variations of this reward-based test are used as a child gets older and finds it easier to communicate.

Testing in older children and adults

Testing in adults mainly uses a technique called pure tone audiometry. This uses a machine called an audiometer to play a series of tones through headphones. The tones vary in pitch (frequency, measured in hertz) and loudness (intensity, measured in decibels). The health professional conducting the test will control the volume of a tone and reduce its loudness until you can no longer hear it. Then the tone will get louder until you can hear it again. You signal by raising your hand or pressing a button every time you hear a tone, even if the tone you hear is very faint. The health professional will then repeat the test several times, using a higher-pitched tone each time. Each ear is tested separately. The results of the test are plotted on a special graph called an audiogram which helps to show the pattern of any hearing loss.

What is Audiometry Used for?

Audiometry is used in a number of different circumstances including:

• To evaluate possible hearing loss in anyone who has noticed a persistent hearing problem in one or both ears or has had difficulty understanding words in conversation.
• When determining the type and amount of hearing loss (conductive, sensor neural, or both).
• Screening babies and young children for hearing problems that might interfere with their ability to learn, speak, or understand language.
• To screen for hearing loss in people who are repeatedly exposed to loud noises or who are taking certain antibiotic medicines, such as gentamicin.