A hearing exam is the first step in determining whether a hearing loss exists and, if so, measures its type, degree and configuration. Hearing testing evaluates the function of the auditory system, including the inner ear and auditory nerve.
Different tests are performed depending on the age and development of the patient. Newborns must be tested using strategies that don’t require participation. Young children may be best assessed using behavioral tests. Adult hearing tests are typically completed using the simplest and most efficient methods available.
Types of Hearing Tests
Auditory Brainstem Response (ABR)
Auditory brainstem response testing is used to determine whether a specific type of hearing loss – sensorineural – exists. It is also frequently used to screen newborns for hearing problems.
In an ABR test, electrodes are attached to your head, scalp or earlobes, and you are given headphones to wear. Your brainwave activity is measured in response to sounds of varying intensities.
This test takes about 30 minutes to complete, though the whole process can take up to two hours.
Otoacoustic Emissions (OAEs)
Otoacoustic emissions (OAEs) are sounds generated by vibrations of the hair cells in the cochlea of the inner ear. OAE testing utilizes a tiny probe fitted with a microphone and speaker that is used to stimulate the cochlea and measure its response. Individuals with normal hearing will produce emissions; when a hearing loss exceeds 25-30 decibels, no sound will be produced.
This test helps determine whether there is a blockage in the ear canal, excess fluid in the middle ear or damage to the hair cells of the cochlea. OAE testing is often included in newborn hearing screening programs.
Tympanometry is a test of the middle ear used to detect fluid, wax buildup, eardrum perforations and tumors. It measures movement of the eardrum in response to air pressure; the results are recorded on a chart called a tympanogram.
Acoustic Reflex Testing
The acoustic reflex test measures involuntary muscle contractions of the middle ear, and is used to determine the location of your hearing problem (the ossicles, cochlea, auditory nerve, etc.) as well as the type of hearing loss.
Pure Tone Audiometry
Pure-tone testing (also known as pure tone audiometry) uses air conduction to measure your ability to hear sounds of various pitches and volumes. Wearing headphones or small foam tips, you will be asked to identify a series of tones by pressing a button.
The results are charted on an audiogram, a graph that shows the type, degree and configuration of your hearing loss by comparing pitch (frequency) with loudness (intensity). The pattern recorded will help your audiologist determine your hearing threshold.
Bone Conduction Testing
Bone conduction testing is another type of pure-tone test that measures the inner ear’s response to sound. If there is damage or a blockage in the outer or middle ear, bone conduction audiometry testing may be used.
Instead of sending the tones through the ear, this type of testing is able to bypass the outer and middle ear and send the tone directly to the inner ear. A small vibrator is placed behind the ear. The device sends out a vibration that passes through the skull bone to reach the inner ear.
If the results of this test are different than the air conduction test, your audiologist can use this information to determine whether you have a conductive or sensorineural hearing loss.
Bone conduction testing is often used in place of air conduction testing when an obstruction in the outer or middle ears is present.
Speech audiometry tests are also performed in a sound booth. You will be asked to repeat a series of words, which will be delivered at various volumes. When the sound becomes very soft, you may need to guess what is being said.
Behavioral Testing for Children
In additional to pure tone and speech testing, we perform tympanometry, reflexes and otoacoustic emissions when appropriate. The type of test used depends on the age and development of your child.
Conditional Play Audiometry (CPA)
CPA is mostly helpful in testing children ranging from two to four years old. Children are taught to perform a simple task (such as putting a block in a bucket) every time they hear a sound. They may be also be asked to point to pictures when they hear the corresponding word.
A parent can accompany the child into the testing booth. A trained testing assistant in the booth is required for this test.
Visual Reinforcement Audiometry (VRA)
This testing technique is used for children 6 to 24 months old. Children are taught to turn toward a moving toy every time they hear a sound (either speech, noise or tonal).
The child usually sits on a parent’s lap during the test and the parent is instructed not to respond to the sounds to avoid inadvertently cueing the child.
Call Heuser Hearing Institute at (502) 584-3573 for more information or to schedule an appointment.