For someone of any age to hear, the ear has to change sound waves into electrical signals which the brain can interpret. This is a complex process, and any malfunction of any part of the ear/hearing apparatus can have hearing loss as a result.
Hearing tests for babies and young children
In newborn babies, when their hearing is tested, clicking sounds are played through an earpiece of headphones and the response from the inner ear and brain is measured. This test can also be used on older children who may have difficulty responding to instructions.
Read: What can be done to help kids hear?
From the age of seven months to about two-and-a-half years, visual reinforcement audiometry (a test in which a child’s ability to link a sound to a visual reward is evaluated), is used. Reducing the sound slowly will give an indication of the level at which a baby/toddler stops hearing a particular sound.
From the age of two to five, a play audiometry test is used, in which a child is given instructions through a headphone or speakers to perform certain tasks. The volume and pitch is then reduced, and it can be seen at which volume the child stops responding to instructions. A graph called an audiogram is used to show the results of this test.
Tests of the middle ear can determine whether there are blockages in the ear canal, and if so, where they are, and whether the eardrum might be perforated.
Hearing tests for older children and adults
For older children, and for adults, a pure tone audiometry test is used in which sounds are played at different tones and frequencies, and the person is asked to indicate when they are able to hear them.
Read: Hearing loss can make elderly feel more isolated
Speech tests are also used in which it is determined what the faintest speech is the person can hear – both with and without background noise. The person being tested is asked to repeat certain words or phrases.
The Otoacoustic Emissions test measures the vibration produced when the cochlea (a part of the inner ear which produces nerve impulses in response to sound vibrations) is stimulated. People who have substantial hearing loss do not produce these sounds/vibrations.
Hearing loss or difficulties can have a profound effect on anyone’s life: it can hamper development in children, and cause serious social problems or problems in the workplace for older people. It is essential to get treatment as soon as possible.
What is hearing loss?
Symptoms of hearing loss
Types of hearing loss
National Health Service: http://www.nhs.uk/Conditions/Hearing-tests/Pages/Introduction.aspx; American Speech-Language-Hearing Association: http://www.asha.org/public/hearing/Hearing-Testing