Presentation on theme: "DEFINING HEARING LOSS hearing impairment the disability category label used in IDEA indicating a hearing loss for which special education and related services."— Presentation transcript:
DEFINING HEARING LOSS hearing impairment the disability category label used in IDEA indicating a hearing loss for which special education and related services are needed deaf not able to use hearing to understand speech Weven with a hearing aid, the hearing loss is too great to allow a deaf child to understand speech through the ears alone Walthough some sounds may be perceived through residual hearing, child uses vision as the primary modality for learning and communication hard-of-hearing a significant hearing loss that makes some special adaptations necessary Wcan understand and respond to speech and other auditory stimuli, generally with the help of a hearing aid Wspeech and language skills, though they may be delayed or deficient, are developed mainly through the auditory channel conductive hearing loss abnormalities or complications of the outer or middle ear cause problems with transmitting sound vibrations to the inner ear Wcan often be corrected through surgical or medical treatment Whearing aids are usually beneficial T 10.1 W. L. Heward, Exceptional Children, 6e, 2000 by Prentice-Hall, Inc. All rights reserved.
DEFINING HEARING LOSS (cont) sensorineural hearing loss caused by damage to the auditory nerve fibers or other sensitive mechanisms in the inner ear Wsound delivered to the brain in a distorted fashion, or not delivered at all Wamplification--making the source of sound louder--may or may not help Wusually cannot be corrected by surgery or medication unilateral hearing loss present in one ear only bilateral hearing loss present in both ears congenital hearing loss present at birth adventitious hearing loss acquired later in life Wprelingual hearing loss sustained before the development of spoken language; educational program focuses on acquisition of language and communication Wpostlingual hearing loss sustained after the development of spoken language; educational program usually emphasizes the maintenance of intelligible speech and appropriate language patterns W. L. Heward, Exceptional Children, 6e, 2000 by Prentice-Hall, Inc. All rights reserved. T 10.2
CAUSES OF HEARING LOSS Prelingual Causes Wmaternal rubella (also known as German measles) can cause deafness, visual impairment, heart disorders, and a variety of other serious disabilities when it affects a pregnant woman, particularly during the first trimester Wheredity with the exception of rubella epidemics, genetic factors are the leading cause of deafness; more than 150 types of hereditary or genetic deafness have been identified Wprematurity and complications of pregnancy early delivery and lower birth weight are more common among children who are deaf than among the general population WCongenital cytomegalovirus (CMV) a viral infection affecting 1% to 2% of all newborns, can result in several conditions, including mental retardation, visual impairment, and most often, hearing loss Postlingual Causes Wmeningitis the leading cause of adventitious hearing loss; a bacterial or viral infection that can destroy the sensitive acoustic apparatus of the inner ear Wotitis media an infection or inflammation of the middle ear; if untreated, can result in a buildup of fluid and a ruptured eardrum, causing permanent conductive hearing loss Wnoise repeated exposure to loud sounds, such as industrial noise, jet aircraft, guns, and amplified music, is increasingly recognized as a cause of hearing loss Although several hundred causes of hearing loss have been identified, the exact cause is unknown for up to 50% of children with hearing loss. W. L. Heward, Exceptional Children, 6e, 2000 by Prentice-Hall, Inc. All rights reserved. T 10.4
IDENTIFICATION AND ASSESSMENT OF HEARING LOSS decibels (dB) standard unit for measuring the intensity of sound W0 dB represents the smallest sound a person with normal hearing can perceive; called the zero hearing-threshold level (HTL), or audiometric zero Wa hearing loss of up to 25 dB is considered within the normal range hertz (Hz) the frequency, or pitch, of sound measured in cycles per second Whumans can hear frequencies ranging from about 20 to 20,000 Hz Wthe frequency range for hearing most spoken language is 500 to 2,000 Hz pure-tone audiometry a formal testing procedure that determines how loud sounds at various frequencies must be before the child is able to hear them Wchild holds up a finger to signal when he hears a sound and lowers it when he hears no sound audiometer an electronic device that generates sounds at different levels of intensity (dB) and frequency (Hz) Wmost deliver tones in 5 dB increments from 0 to 120 dB Weach dB level presented in various frequencies usually starting at 125 Hz and increasing in octave intervals (doubling in frequency) to 8,000 Hz audiogram a chart showing the results of an audiometric test Wto obtain a hearing level on an audiogram, child must be able to detect a sound at least 50% of the time W. L. Heward, Exceptional Children, 6e, 2000 by Prentice-Hall, Inc. All rights reserved. T 10.5
EFFECTS OF HEARING LOSS ON ENGLISH LITERACY AND ACADEMIC ACHIEVEMENT WA child with a hearing lossespecially a prelinguistic loss of 90 dB or greateris at a great disadvantage in acquiring English language skills. WHearing children typically acquire a large vocabulary and a knowledge of grammar, word order, idiomatic expressions, fine shades of meaning, and many other aspects of verbal expression by listening to others and to themselves from early infancy. A child who, from birth or soon after, is unable to hear the speech of other people will not learn speech and language spontaneously, as do children with normal hearing. WSince reading and writing involve graphic representations of a phonologically-based language, the deaf child must strive to decode and produce text based on a language for which he may have little or no understanding. WDeaf students typically have smaller vocabularies and their sentence structures are simpler and more rigid than those of hearing children of the same age or grade level. WBecause the grammar and structure of English often do not follow logical rules (e.g., if the past tense of talk is talked, then why doesn't go become goed?), and a person with prelingual hearing loss must exert a great deal of effort to read and write with acceptable form and meaning. WThe median grade level for reading comprehension of deaf students ages 16 to 18 years ranges from 2.9 to 3.2; for arithmetic computation, it ranges from 7.0 to 7.5. WSign languagea visual-spatial languageis the first language for many deaf persons. Attempting to assess the intelligence of a deaf individual by his understanding and use of Englisha phonologically based second language to which this person has had limited accessis just as inappropriate as using an English language assessment battery to classify a child whose first language is Spanish. W. L. Heward, Exceptional Children, 6e, 2000 by Prentice-Hall, Inc. All rights reserved. T 10.7
ORAL/AURAL APPROACHES Speech is viewed as essential if students who are deaf are to function in the hearing world. Training in producing and understanding speech and language is incorporated into virtually all aspects of the child's education. Wused widely in the United States before the 1970s, a purely oral approach is now used by about one-fourth of educational programs for students with hearing loss Wmuch attention is given to amplification, auditory training, speechreading, the use of technological aids, and, above all, talking Wa few programs maintain a purely oral environment and may even prohibit children from pointing, using gestures, or spelling out words to communicate Wa few oral programs use cued speech, a method of supplementing oral communication with hand signals near the chin to assist in identifying sounds that cannot be distinguished through speechreading Weducators who use an oral approach acknowledge that teaching speech to children who are deaf is difficult, demanding, and time-consuming Wmost students with hearing losses no worse than severe can learn speech well enough to communicate effectively with hearing people Wthe best results are obtained with students in indisputably comprehensive oral programs or who are integrated most of the school day into regular education programs W. L. Heward, Exceptional Children, 6e, 2000 by Prentice-Hall, Inc. All rights reserved. T 10.8
TOTAL COMMUNICATION total communication the simultaneous presentation of manual communication (by signs and fingerspelling) and speech (through speechreading and residual hearing) to teach language to students with hearing loss W advocates believe it makes it possible for children to use either one or both types of communication, depending on the situation W since the 1960s, has become the predominant method of instruction in schools for the deaf W teachers who practice total communication generally speak as they sign and make a special effort to follow the form and structure of spoken English sign language use of gestures to represent words, ideas, and concepts W some signs are iconic; they look like or appear to imitate or act out their message (e.g., the signs for cat and eat) W most signs, however, do not resemble the objects or actions they represent W if sign language were simply a form of pantomime, then most nonsigners would be able to understand it with relatively little effort fingerspelling consists of 26 distinct hand positions, one for each letter of the English alphabet (see Transparency 10.10) W used to spell out proper names for which no sign exists and to clarify meanings W. L. Heward, Exceptional Children, 6e, 2000 by Prentice-Hall, Inc. All rights reserved. T 10.9
AMERICAN SIGN LANGUAGE (ASL) American Sign Language (ASL) is the language of the Deaf culture in the United States and Canada. Walthough sign languages by native deaf speakers were once thought of as non-languages, ASL is now viewed as a legitimate language in its own right Wa visual-gestural language with its own rules of phonology, morphology, syntax, semantics, and pragmatics Wthe shape, location, and movement pattern of the hands; the intensity of motions; and the signer's facial expressions all communicate meaning and content Wstructured to meet eye and motor capabilities of the body; grammatical structure is spatially based Wbecause ASL has its own vocabulary, syntax, and grammatical rules, it does not correspond to spoken or written English Wdifficult to make precise word-for-word translations between ASL and English W. L. Heward, Exceptional Children, 6e, 2000 by Prentice-Hall, Inc. All rights reserved. T 10.11
BILINGUAL-BICULTURAL APPROACH W Proponents of a bilingual-bicultural approach view deafness as a cultural and linguistic difference, not a disability, and recognize American Sign Language (ASL) as the deaf child's natural language. W Both the Deaf community, as well as a growing number of hearing special educators, are calling for the use of ASL as the language of instruction. W They believe that ASL provides a natural pathway to linguistic competence and that English is better learned in the context of a bilingual- bicultural education after the child has mastered his or her native or first language (ASL). W The goal of the bilingual-bicultural education approach is for the deaf student to become a bilingual adult who is competent in both his or her first language, ASL, and can read and write with competence in his or her second language, English. W Empirical support for the bilingual-bicultural approach comes from some recent research finding that early exposure to and development of fluency in ASL are associated with increased competence and English literacy (reading and writing). W. L. Heward, Exceptional Children, 6e, 2000 by Prentice-Hall, Inc. All rights reserved. T 10.12
AMPLIFICATION AND AUDITORY LEARNING hearing aid a miniature amplification instrument that makes sounds louder W dozens of different kinds; can be worn behind the ear, in the ear, on the body, in eyeglasses W can help many children by increasing their awareness of sound W makes sounds louder but not necessarily clearer W even the most powerful models do not enable children with severe and profound hearing losses to hear speech sounds beyond a distance of a few feet W does not cure a hearing loss or by itself enable a child who is deaf to function normally in the classroom W the earlier in life a child is fitted with an appropriate hearing aid, the better W to derive the maximum benefit, must be worn throughout the day W residual hearing is not developed by removing or turning the hearing aid off W classroom amplification systems can augment the childs personal hearing aid auditory learning helps children make better use of residual hearing; includes four steps or levels: awareness sensing the presence and absence of sound localization locating the source of sound discrimination differentiating between sounds identification recognizing and comprehending the meaning of a sound W. L. Heward, Exceptional Children, 6e, 2000 by Prentice-Hall, Inc. All rights reserved. T 10.13
SPEECHREADING speechreading the process of understanding a spoken message by observing the speaker's face W traditionally called lipreading--some sounds are readily distinguished by watching the speaker's lips (e.g., the words pail and rail) W careful attention to a speaker's lips may help, but understanding speech from visual clues involves more than simply looking at the lips W important clues are obtained from signs or gestures, facial expressions, and familiarity with the context or situation Speechreading is extremely difficult and has many limitations: W about half of all English words have some other word(s) that look alike on the lips (e.g., bat, mat, and pat) W visual clues may be blocked by a hand or a pencil, chewing gum, or a mustache W many speakers hardly move their lips and are unintelligible through speechreading W it is extremely tiring to watch lips for a long time W it may be impossible to speechread at a distance, such as during a lecture W even the best speechreaders detect only about 25% of what is said through visual clues alone Despite the problems inherent in speechreading, it can be a valuable adjunct in the communication of a deaf or hard of hearing person. T 10.14 W. L. Heward, Exceptional Children, 6e, 2000 by Prentice-Hall, Inc. All rights reserved.