Hearing loss and deafness affect individuals of all ages and may occur at any time from infancy through old age. The U.S. Department of Education (2000) reports that, during the 1998-99 school year, 70,813 students aged 6-21 received special education services under the category of "hearing impairment."
Hearing impairment is defined by the Individuals with Disabilities Education Act (IDEA) as, "[...] an impairment in hearing, whether permanent or fluctuating, that adversely affects a child's educational performance."
Deafness is defined as, "[...] a hearing impairment that is so severe that the child is impaired in processing linguistic information through hearing, with or without amplification." A child with hearing loss can generally respond to auditory stimuli, including speech.
There are four types of hearing loss. Conductive hearing losses are caused by diseases or obstructions in the outer or middle ear. Conductive hearing losses usually affect all frequencies of hearing evenly and do not usually result in severe losses.
While hearing impairment is a sensory deficit, the consequences can be far-reaching and include delays in the acquisition of speech and language skills. Language deficits can lead to compromise in intellectual and socio-emotional development and markedly impact the quality of an individual's life, including educational and vocational achievement.
Sensorineural hearing losses result from damage to the delicate sensory hair cells of the inner ear or the nerves which supply it. These hearing losses can range from mild to profound. They often affect the person's ability to hear certain frequencies more than others. A mixed hearing loss refers to a combination of conductive and sensorineural loss and means that a problem occurs in both the outer or middle and the inner ear.
A central hearing loss results from damage or impairment to the nerves or nuclei of the central nervous system, either in the pathways to the brain or in the brain itself.
Examples, Subsets and Synonyms for Hearing Impairment -- Hearing Loss, Deafness:
- Conductive Hearing Loss
- Sensorineural Hearing Loss