Hearing Screening

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, you will be asked to identify a series of tones by raising a hand, pressing a button, or responding verbally. 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 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.

Alternatively, a two-pronged metal tuning fork may be placed behind the ear or on the forehead. When vibrated, it produces a tone that travels to the cochlea via the skull. Your response determines how well sound travels through different parts of your ear, helping the audiologist diagnose your type of 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 (or word recognition) testing is used to measure your speech reception threshold (SRT), or the faintest speech you can understand 50% of the time. This is compared with your pure-tone test results to confirm the diagnosis. In addition, your ability to separate speech from background noise will be recorded. Speech testing may be administered in either a quiet or noisy environment; results are recorded on the audiogram for easy visual reference.

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.

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.

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.

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 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.