Editor: Anne Lynn S. Chang ISBN: 978-1-58765-384-1 List price: $395 Click here to view the entire essay covering hearing loss as it appears in Magill's Medical Guide. Click here to view more Curious Questions from Magill's Medical Guide.

Magill's Medical Guide covers diseases, disorders, treatments, procedures, specialties, anatomy, biology, and issues in an A-Z format, with sidebars addressing recent developments in medicine and concise information boxes for all diseases and disorders. Below is an excerpt from the Guide's essay on hearing. Hearing Loss In the truest sense, hearing loss is any reduction in threshold sensitivity for any frequency, including those below or above the range for the normal hearing of speech. The real issue, however, is whether minor changes in sensitivity create significant problems in understanding speech and other information-bearing acoustic signals. For example, it is known that loss of threshold sensitivity below 300 hertz and above 4,000 hertz has a minimal effect on understanding speech information. It is when hearing loss exists within this critical frequency range that an individual may experience appreciable difficulty in understanding intended messages. The question becomes, then, "What conditions may cause a permanent or temporary loss of hearing, and how is such a loss managed by medical, surgical, or rehabilitative intervention?" Conductive Hearing Loss. Any barrier or impedance that keeps sound from reaching the cochlea of the human auditory system at its intended loudness is termed "conductive hearing loss." The most common cause of conduction loss is a buildup of earwax in the external ear canal. The production of earwax in the ear is essential. It prevents the skin of the ear canal from drying and sloughing off, and it may serve to trap minute foreign particles and keep them from causing damage to the external canal. Normally, earwax will migrate out of the ear and create no conduction problem. It is when the earwax accumulates to an amount sufficient to block sound from entering the ear that something needs to be done. In most cases, earwax can be removed by irrigation. A physician washes out the earwax using a special liquid solution that does not damage the tissue of the ear canal or the eardrum itself.

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