Patients who suffer from hearing loss, or other hearing-related conditions, may benefit from audiologic testing. Comprehensive diagnostic exams can determine the causes and severity of, and best treatment for, hearing-related conditions. Audiologic tests are usually performed after other diagnostic tests have indicated the presence of a possible hearing problem.
Diagnostic audiological evaluations for children and adults commonly include:
This hearing test uses sounds of specific frequencies and intensity levels to determine what a person can hear in each ear. The sounds are heard through headphones, and the patient is asked to identify each sound and the ear in which it was heard. The sounds become fainter and fainter, ultimately determining the lowest level at which a patient can hear. An audiogram may also include speech in the form of two-syllable words to determine how well a patient can comprehend what is being heard.
A modified version of the diagnostic audiogram, play audiometry is sometimes used when working with preschool and younger school-age children. The sounds are heard through headphones, but rather than raising a hand to indicate hearing a sound, the child places a toy in a container.
This form of testing examines and diagnoses problems in the middle ear by varying air pressure in the ear canal to see how the ear responds. A probe is inserted into the ear to change the air pressure, produce a tone and measure the responses. The patient may not speak, move or swallow during the test because doing so can affect ear pressure. Tympanometry measures the functionality of the eardrum (tympanic membrane). Abnormal findings may be the result of fluid in the middle ear, a perforated ear drum or impacted ear wax.
Brainstem Auditory Evoked Response Test
The brainstem auditory evoked response test (BAER) examines brain waves that have been stimulated by a clicking sound in order to evaluate the auditory pathways in the brain. Electrodes are placed on the scalp and earlobes, and the patient listens to a clicking noise through headphones. The BAER test is commonly conducted to diagnose hearing loss in infants or children.
Otoacoustic Emissions Testing (OAE)
Otoacoustic emissions testing (OAE) measures response to a sound from the cochlea, or the inner part of the ear. The hair cells inside the cochlea vibrate in response to sound. These vibrations produce a nearly inaudible sound that echoes back into the middle ear.
This test is performed by inserting a microphone and two speakers into the ear to emit a sound and then record the response signal. The test is often performed on children when hearing loss is a possibility. An OAE may also be conducted as part of the newborn hearing screening process. Absent or very soft response signals may be a sign of hearing loss, fluid behind the ears or damage to the cochlea.