Prevalence, Definitions, and Characteristics
Individuals with hearing impairments make up .11% of the school-age population, and 1.2% of the students served under IDEA (U.S. Department of Education, 2005). Hearing impairments range in severity from mild to moderate to severe to profound, with the greatest educational distinctions occurring between hard of hearing and deaf. Individuals classified as hard of hearing can hear speech tones when wearing hearing aids, while persons who are deaf cannot hear even with hearing aids.
The age that a child loses hearing affects the degree of language delay and development. Children who are born with deafness have congenital hearing losses (prelingual) and more difficulty with language development than those who acquire deafness after age 2 (postlingual).
Pure tone audiometers are used to assess hearing ability. Tones with different pitches (or frequency measured in Hertz [Hz]) and volume (measured in decibels [dB]) are presented via headphones, and individuals raise their hand when they hear a sound. Levels of hearing impairment are classified along a continuum, with reference to zero dB indicating the quietest sound a person with normal hearing can detect. Individuals with slight hearing losses (27–40 dB) may not have difficulty in most school situations. Individuals with mild losses (41–55) may miss up to 50% of classroom discussion if voices are faint or faces cannot be seen. Individuals with moderate losses (56–70 dB) can understand only loud speech, and may have limited vocabularies. Individuals with severe losses (71–90 dB) may be able to hear loud voices within one foot from the ear, and speech is likely to be impaired. Individuals with profound losses (> 90 dB) may hear some loud sounds, but are more likely to sense vibrations, and may rely on vision rather than hearing as a primary vehicle for communication (Heward, 2006). Specialized tests are needed to accurately assess the cognitive and academic functioning of individuals with hearing impairments (Owens, Metz, & Haas, 2003).
Causes of hearing impairments include heredity, prenatal infections such as maternal rubella, ear infections, meningitis, head trauma, prematurity, and oxygen deprivation. Impairments can be conductive, meaning the outer or middle ear along the passageway are damaged; sensorineural, referring to inner ear damage; or they can be a combination of the two (Owens, Metz, & Haas, 2003).
Many children with hearing impairments have academic and cognitive deficiencies or developmental lags due to difficulties processing language (Meadow-Orlans, 1990). Some children experience social-emotional functioning difficulties due to communication difficulties (Luterman, 1996).
An ongoing debate exists over what should be considered the best approach for teaching individuals with severe hearing impairments. Some advocate total communication (Owens, Metz, & Haas, 2003), which involves using speech (lip) reading, gestures, and sign language, or both oral and manual methods. Teachers using total communication rely on the structure of the English language, and speak while signing during communications with students who are deaf. Some advocate the use of only oral approaches, eliminating any manual components used in total communication. Teachers using only oral approaches rely heavily on parental and family involvement as well as auditory, visual, and tactile methods of presentation. Finally, others advocate using only sign language or manual approaches. These individuals advocate the exclusive use of sign language because they maintain that a unique “culture of the deaf” exists among those who communicate with sign language. They believe that when individuals with hearing impairments are taught only to speech read or use oral techniques, they are denied full participation in the culture of the deaf (Owens, Metz, & Haas, 2003; Reagan, 1990). Individuals from this position say they are not disabled, but that they are part of another cultural group composed of individuals who are deaf.
Several signing systems are in use today, including the American Sign Language (ASL), Fingerspelling, and Signing Exact English. All systems use manual signs made with the hands and fingers to represent words, concepts, and ideas. However, they are based on different systems. The American Sign Language (ASL) is a visual-spatial language, is not phonologically based like English, and is the official language of the culture of the deaf in the United States. ASL has its own rules of semantics, syntax, and pragmatics, and vocabulary (Owens, Metz, & Haas, 2003). Fingerspelling is a manual alphabet of 26 distinct hand positions used to represent each letter in the English alphabet. Fingerspelling is especially appropriate for unfamiliar words such as proper names. The following In the Classroom feature displays sample sign language positions and fingerspellings. Some teachers use Fingerspelling while speaking to students with hearing impairments. Signing Exact English is a system that employs components of ASL, but attempts to use correct English usage for facilitating the learning of reading and writing literacy skills in English for students who are deaf. No clear research evidence exists to promote one approach over the other in teaching students who are deaf. Therefore, it is likely that this debate will continue into the future.
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