A pure tone audiometry test measures the softest, or least audible, sound that a person can hear. During the test, you will wear earphones and hear a range of sounds directed to one ear at a time. The loudness of sound is measured in decibels (dB). The tone of sound is measured in frequencies (Hz). Normal hearing range is 250-8,000 Hz at 25 dB or lower.
A word recognition test (also called speech discrimination test) assesses a person's ability to understand speech from background noise. If your speech discrimination is poor, speech may sound garbled. Word recognition scores can be helpful in predicting the usefulness of a hearing aid.
A tympanometry test detects problems such as fluid/wax buildup, perforated eardrum, ossicle bone damage, or tumors in the middle ear. Acoustic reflex testing evaluates the cranial nerves and brainstem.
An otoacoustic emission test (OAE) measures an acoustic response that is produced by the inner ear (cochlea), which in essence bounces back out of the ear in response to a sound stimulus. The test is performed by placing a small probe that contains a microphone and speaker into the infant's ear. As the infant rests quietly, sounds are generated in the probe and responses that come back from the cochlea are recorded. Once the cochlea processes the sound, an electrical stimulus is sent to the brainstem. In addition, there is a second and separate sound that does not travel up the nerve, but comes back out into the infant's ear canal. This "byproduct" is the otoacoustic emission. The emission is then recorded with the microphone probe and represented pictorially on a computer screen. The audiologist can determine which sounds yielded a response/emission and the strength of those responses. If there is an emission present for those sounds that are critical to speech comprehension, then the infant has "passed" the hearing screen.
Testing Newborns & Children
Hearing Evaluations for Children
A hearing test for a child is often not as simple as a hearing test for an adult. For this reason, audiologists are trained in specific techniques to evaluate the hearing of a child. Toys, games, and lights are used in the testing room to help obtain responses from a child to soft tones, noises, or words. The child may wear headphones or listen to the sounds in a room with speakers.
Newborn Hearing Screenings
The majority of infants born in hospitals are screened for hearing before going home. This type of hearing test uses small headphones and stickers that attach to the baby’s skin. A soft clicking sound is played in each ear, and a computer measures the brain’s response to the sound. The baby sleeps during this short, painless test. Babies who did not receive a hearing screening at birth should be screened within the first month of life./**/