There are a number of tests that can be used in hearing evaluations. Of those, there are five major categories: pure-tone testing, speech testing, middle ear testing, Auditory Brainstem Response (ABR) and Otoacoustic Emissions (OAEs).
Pure-tone testing determines the faintest tones you can hear at a variety of pitches. You will be asked to wear specially designed headphones and sit in a sound booth. A series of tones will be played in each ear, every time you hear a tone you will raise your hand or press a button. At the end of this test, the results are recorded on an audiogram. This is a visual representation of how well you can hear, specially, the loudness (decibels) of each pitch (hertz) you can identify.
This test can be used on a children as young as 6 months old. Instead of using headphones, the sounds are broadcast through speakers in a specially designed booth. Since it is unlikely you could get a 6 month old to raise their hand every time they hear a sound, visual reinforcement is used. The child is rewarded by watching a toy move every time they look towards the sound when they hear it. For children ages 2 to 5 conditioned play is used. The child is asked to perform an activity, such as placing a block in a box every time they hear a tone.
Speech testing is used to identify how well you can understand spoken words. Your speech reception threshold (SRT) and your speech detection threshold (SDT) will be determined, with the results recorded on the audiogram. The tester will read a list of words aloud. One version of this test only requires you to indicate if you heard the words. Another version requires you to recite the list back to the tester. The results from speech testing are often used to confirm the results obtained from the pure-tone testing.
There are a number of middle ear tests, all of which provide information on how the middle ear is functioning. These tests are used most often on preschool aged children, as they are prone to middle ear infections. Tympanometry tests if there is fluid within the middle ear, if you have a perforated eardrum or if there is wax blocking the ear canal. Air is pushed into the ear canal and a measurement is taken of how much the eardrum is able to move back and forth. An acoustic reflex measure helps to determine the location of the hearing problem. Loud tones are presented to the middle ear and the reaction of tiny muscles in the ear is measured. Static acoustic impedance measures the volume of air within the middle ear. This is a helpful test to see if you have a perforated eardrum and to see if the tubes responsible for ear ventilation are working properly.
Auditory Brainstem Response (ABR), often called auditory evoked potential (AEP), tests how well your cochlea and the neural pathway that connects your inner ear to the brain are functioning. Electrodes are placed around your head and ear and you are asked to lay still for the duration of the two-hour test. Your brain wave activity in response to a variety of sounds is measured.
This test can be used on those that are unable to participate in a more subjective hearing test, specifically young children. Since a young child is unlikely to stay still for the whole test, a sedative may be administered beforehand. A simplified version of this test is used as part of newborn hearing screenings.