There are a number of different audiological tests used to assess a child’s hearing and auditory function. Typically, an audiologist will use a number of different tests together to provide a complete “picture” of the child’s hearing status and function of the auditory system. The ages of children appropriate for audiological tests should be considered in relation to the developmental age of the child if the child is functioning below his/her chronological age.
- Otoacoustic Emissions Testing (OAE, DPOAE, TEOAE)
- Brainstem Audiometry Evoked Response (BAER, BSER, BAER, ABR)
Behavioral Hearing Tests
How it is done: A small earphone is placed in the ear canal and sounds are presented. An otoacoustic emission test measures an acoustic response produced by the inner ear (cochlea). The acoustic response measured is the response produced by the inner ear in response to a sound stimulus from the earphone. The OAE tests take about 10 minutes to perform in a quiet child.
Who it is for: The OAE test is often used for newborn hearing screening and re-screening of infants up to 6 months of age, or for children who cannot respond to other types of behavioral hearing tests.
What it will show: The OAE test is interpreted with pass/fail criteria. If the child passes the OAE test, there are no concerns about the child’s hearing, but if the child does not pass the OAE test, the child is demonstrating at least a mild hearing loss. The OAE test does not distinguish the degree or type of hearing loss.
How it is done: The BAER test is a physiologic test that measures the function of the entire auditory system and the brain’s response to sound. This test can only be done if the child is either asleep or sedated. Electrodes are attached to the child’s head and behind the ears. Sounds are presented through the earphone and the electrodes measure the response of the child’s hearing system. This test gathers specific information about the responses of the child’s auditory system at different frequencies and hearing levels. A diagnostic BAER testing typically takes one hour of testing.
Who it is for: This test is used for infants up to 6 months of age, and for children who cannot respond to other types of behavioral hearing tests. The BAER test may be used for newborn hearing screening.
What it will show: The BAER provides information about the degree of hearing loss and the type of hearing loss across different test frequencies (pitches). Earphone and bone conduction testing will determine the type of hearing loss (sensorineural vs conductive).
Behavioral Hearing Tests
How it is done: During VRA testing, a child is seated on an adult’s lap in a sound proof booth. Auditory stimuli are presented and the child is trained to turn to the sound and is then rewarded with an animated toy. The sounds, or auditory stimuli used are tones, noise bands, and speech stimuli and can be presented by earphones, loudspeakers, and bone conduction.
Who it is for: Children from 6 months of age to 2 ½ years can be tested using visual reinforcement audiometry.
What it will show: By using this technique, it is possible to obtain information about the child's hearing thresholds across frequencies. If only sound field (loudspeaker) testing is used, then the results give information about hearing in at least one ear. Hearing thresholds will typically be plotted on an audiogram.
How it is done: Play audiometry is a game-like activity where the child is taught to do a specific task, such as dropping a block in a bucket, every time a sound is heard.
Who it is for: Children from 2 to 4 years of age
What it will show: As with VRA, it is possible to obtain detailed information about the child's hearing thresholds across frequencies in both ears. At this age, children often accept earphones more readily, so that ear-specific information can be obtained. If needed, bone conduction testing can be completed, as well. Hearing thresholds will typically be plotted on an audiogram.
How it is done: A child is seated in a sound proof booth and sounds are presented by earphones. The child is taught to raise a hand each time a sound is heard. The softest sounds that the child can hear, called hearing thresholds are recorded.
Who it is for: By the age of 5 years, children are able to reliably respond using conventional audiometry. This method is used through adulthood.
What will it show: Hearing thresholds are measured in each ear using headphones or earphones, and bone conduction, if necessary. Hearing thresholds will typically be plotted on an audiogram.
How it is done: Tympanometry is performed by placing a small probe earphone in the child's ear canal and gently changing the air pressure in the ear. The procedure takes a few seconds per ear.
Who it is for: Children and adults of all ages can be tested using tympanometry.
What will it show: Tympanometry is used to determine the function of the outer and middle ear. This test is important because fluid in the middle ear or other abnormalities can affect hearing. A normal tympanogram shows a peak on a graph, showing compliance, or movement of the eardrum as a function of changing pressure. A typical abnormal tympanogram in a child is a flat function, showing middle ear fluid.
Figure 4: Normal tympanogram
Figure 5: Flat tympanogram
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