Audiology refers to the study of hearing and audiology centers are commonly part of a comprehensive otolaryngology practice. Our hearing specialists (a.k.a. audiologists) work closely alongside Dr. Bailey to identify sources of hearing loss and formulate solutions that can restore hearing and quality of life. With the help of the latest diagnostic equipment available, our audiologists can evaluate and treat the various hearing disorders in both children and adults.
Audiometric tests evaluate hearing by measuring the transmission of sound from the external environment to the brain. Sound waves are vibrations of air, fluid or solid material in the environment. The speed at which they vibrate is measured as the frequency and this determines how high or low the pitch of the sound is. The amplitude, which is the height of the sound wave, translates into how loud the sound is. Hearing occurs when sound waves travel through the ear canal and eardrum and are then turned into nerve impulses that travel from the inner ear to the brain. If the nerve impulses reaches the brain, hearing has occurred.
The following table describes the varying degrees of hearing loss according to decibel range and how it relates to one’s ability to hear speech.
Hearing Loss Table
|Hearing threshold in decibels (dB)||Degree of hearing loss||Ability to hear speech|
|0-25 Db||None||No significant difficulty|
|26-40 dB||Mild||Difficulty with faint or distant speech|
|41-55 dB||Moderate||Difficulty with conversational speech|
|56-70 Db||Moderate to severe||Moderate to severe|
|71-90 dB||Severe||Difficulty with loud speech; understands only shouted or amplified speech|
|91+ Db||Profound||May not understand amplified speech|
Hearing tests help monitor hearing in developing children and to evaluate for types of hearing loss. Hearing is vitally important in the development of speech, the ability to learn, understand language and interact with society. Hearing tests will also determine the type and degree of hearing loss. When the movement of sound (conduction) is obstructed and does not pass into the inner ear, it is known as Conductive Hearing Loss. Ear wax impaction or a growth in the ear canal are examples of conductive hearing loss. If, however, sound reaches the inner ear, but the brain never receives any kind of message that a sound is present, the problem may lie in the nerves that transmit impulses to the brain and is called Sensorineural Hearing Loss. Occasionally, a growth or damage to the areas of the brain that interpret sound may be the cause of the hearing loss. Hearing tests are frequently performed by an audiologist (a hearing specialist) in a hearing clinic or otolaryngologist’s office. They are also commonly performed in schools or the workplace by other allied health professionals such as speech pathologists, psychologists, nurses, or audiometric technicians.
Types of Hearing Tests
Pure Tone Audiometry
Using a machine called an audiometer, a series of tones varying in pitch and loudness are played through headphones. The volume is reduced until it is no longer heard and then increased until it is heard again. This is repeated for each pitch and helps determine at what pitch and frequency hearing loss is present.
Whispered Speech Test
Often performed in the doctor’s office where other specialized hearing equipment are not available, the whisper test can help document the presence of hearing loss in the right or left ear but cannot differentiate between conductive or sensorineural hearing loss nor at what frequency and pitch the hearing loss occurs at.
Tuning Fork Test
Tuning forks can aid in determining the source of hearing loss. When hit, the tuning fork produces vibrations and sound. It is placed in front of the ear and on the bone behind the ear. Sound heard when the fork is in front of the ear, indicates intact conductive hearing. If the sound is heard by placing the fork on the bone of the skull (the mastoid process behind the ear), sensorineural hearing is intact.
Speech Reception and Word Recognition Tests
These tests not only measure the ability to hear sound but also the ability to hear and understand normal conversation. A series of simple words are spoken and repeated with different degrees of loudness. When half of the list of familiar two-syllable words test become difficult to understand, documentation will be made and evaluated for appropriate therapy.
Otoacoustic Emissions (OAE) Testing
Used to screen newborns for hearing problems, a small, soft microphone introduces sound into the baby’s ear canal through a small flexible probe. The microphone then detects how the inner ear responds to the sound. The test is helpful in determining whether hearing loss is present, but is doesn’t identify the type or degree of hearing loss.
Auditory Brainstem Response (ABR) Testing
Also known as the brain stem auditory evoked response (BAER) testing or auditory brainstem evolved potential (ABEP) testing, this test is performed to primarily detect sensorineural hearing loss. Electrodes that are placed on the scalp and on each earlobe, monitor the brain’s response to clicking noises being transmitted through earphones.