About Hearing
Hearing
What Is A Hearing Loss & What Does It Mean?
The results of a hearing examination are graphed on an audiogram, which records a person's hearing capabilities. By creating an audiogram, a Preferred Hearing Solutions specialist can illustrate the person's ability to hear sounds at different frequencies. Hearing levels from -10 to 25 dB are considered within normal limits (see Figure 1.1).
Figure 1.1

During a hearing examination, the person's ability to hear tones is measured. The intensity of the test tones is varied until the level is determined that the person can just hear the tones. This 'barely-heard' level is the "hearing threshold level." In Figure 1.2, which demonstrates a moderate to severe hearing loss in the high frequencies, the person can just barely hear the 4000 Hz tone at the 55 dB level. For a normal-hearing person, this 55 dB tone would be comfortably loud.
Fig 1.2

Symptoms of a Hearing Loss
While individuals losing hearing ability at different frequencies, this patient’s hearing loss (Figure 1.3) will manifest itself in several ways. Most significantly, because consonants are spoken at higher frequencies and vowels at lower frequencies, this person will have a difficult time hearing consonants spoken in normal conversation. The effects of hearing loss can be severe, often dramatically changing the affected person’s lifestyle. In adults, it creates coping mechanisms, which may include isolation from family and friends and a reluctance to participate in public events. In children, hearing loss may negatively affect their ability to learn, the development of their communication skills and their ability to interact with others.
Figure 1.3

The following table describes the loudness of some common situations and noises.
| dB | Sound |
| 140 | Threshold of Pain |
| 125 | Jet Take-Off at 100 Meter Distance |
| 110 | Rock Group |
| 90 | Heavy Truck |
| 85 | Average Street Traffic |
| 60 | Conversational Speech |
| 35 | Library |
| 0 | Threshold of Hearing |
Types of Hearing Losses
The major cause of hearing loss in children is ear infections. Hearing loss in children can also be caused by birth defects, disease, and injury. The major causes of hearing loss in adults are noise exposure, disease, injury and aging (presbyacusis).
Hearing loss can occur at different places in the auditory system and is classified according to which portion of the ear structure is affected. Disorders affecting the outer or middle ear result in a conductive hearing loss. These types of hearing loss reduce the volume or loudness of the sound reaching the inner ear, but do not necessarily cause distortion of pitch or loudness. Conductive hearing losses are most often considered to be temporary and can be caused by excessive ear wax, foreign objects placed in the ear canal, fluid in the middle ear or damage to the eardrum or middle ear mechanism. A conductive hearing loss component of 15db or greater in three frequencies requires a hearing instrument specialist to refer his patient to an otolaryngologist, or an ear-nose-throat specialist, for possible correction.
Hearing loss involving the inner ear or cochlea is called sensory or auditory, and the hearing loss involving the nerve is called neural. Classified together they are referred to as a sensorineural hearing loss, or commonly referred to as "nerve deafness". They can be further divided as cochlear, or just the inner ear by itself; or retrocochlear, which indicates the auditory neural or brainstem. Sensorineural hearing losses not only reduce the loudness of sounds reaching the brain, but also tend to distort sounds so they do not reach the inner ear as clearly. If the nerve and brainstem portions are also involved, then greater distortions impair the clarity or intelligibility of the speech sounds reaching the brain. " If the loss is in the inner ear, then it is "cochlear," which is also called sensorineural. If a person has conductive and cochlear hearing loss combined, it is termed "mixed." A person can also have hearing loss associated with the central auditory nervous system (CANS) which includes the auditory nerve, the brainstem, and the brain. Sensorineural loss can be caused by aging, extended exposure to loud noise, use of ototoxic drugs, and certain diseases.
For more information about a hearing loss and what it means, call Preferred Hearing Solutions @ 951-652-9655, 951-303-8886 or This e-mail address is being protected from spambots. You need JavaScript enabled to view it
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Last Updated (Monday, 11 May 2009 13:26)
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