Most people think of hearing tests as merely raising their hand when they hear a soft beeping sound. This is only a small part of a routine hearing evaluation . After the audiologist examines the ear canals for excessive ear wax or other debris, the person is seated in a sound-treated room which allows for the detection of extremely soft sounds. Initially, soft tones are presented and the patient is asked to signal that the tone is heard by either pressing a button or raising his or her hand. Next, two-syllable words are presented and the person is asked to repeat the words. Then, the patient is asked to repeat one-syllable words at a level determined to be the most comfortable and clear. Most comfortable listening levels and uncomfortable listening levels are obtained using speech and tones. Using these tests, your audiologist can determine whether a hearing loss exists and, if so, its degree and type.
The degree of hearing loss is determined based on the loudness required for a person to hear the soft beeping tones, measured in decibels.
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Hearing losses may be categorized as conductive, sensorineural, a combination of the two called mixed, or retrocochlear.
Conductive hearing loss is caused by a problem of the outer ear (ear canal) or middle ear (ear drum, tiny ear bones, or the space containing those bones). Conductive hearing loss is quite often medically treatable. When a conductive loss is identified, the patient must be referred to a physician, preferably one specializing in the treatment of ear, nose and throat diseases, for evaluation and possible treatment. Some of the most common causes of conductive hearing loss are ear infections (otitis media), trauma to the ear, otosclerosis (a problem with the tiny bones of the ear) and foreign objects in the ear canals.
Sensorineural hearing loss ("nerve" or "inner-ear" hearing loss) is usually caused by a problem with the actual organ of hearing that turns sound into nerve energy. In most cases of sensorineural hearing loss, the tiny hair cells that respond to sound in the inner ear are damaged and cannot send that sound to the nerve and up to the brain. Sensorineural loss is usually permanent and not medically treatable. Fortunately, most sensorineural losses can be treated successfully with hearing aids . The two most common causes of sensorineural hearing loss are noise exposure and the normal aging process.
Retrocochlear hearing loss. Occasionally, sensorineural
hearing loss is related to an actual problem with the hearing nerve or parts
of the brain which process speech. These types of losses are called
retrocochlear disorders. When a retrocochlear
disorder is suspected, additional tests such as
auditory brainstem response
(ABR) or electronystagmography
(ENG) may be recommended to provide additional information.
Otoacoustic emissions
(OAEs) also may be of benefit in evaluating such hearing losses. Patients
with suspected retrocochlear disorders are referred to a physician for further
evaluation.
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