Download 9-10 Types of Hearing Loss

Exceptional Children
An Introduction to Special Education
Tenth Edition
William L. Heward
© 2013, 2009, 2006, 2003, 2000
Pearson Education, Inc. All rights reserved.
Chapter 9
Deafness and Hearing Loss
Focus Questions
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What distinguishes a child who is deaf from a child who is
hard of hearing in terms of the primary sensory mode used
for learning and communication?
How might deafness affect a child’s acquisition and use of
speech and language, academic achievement, and social
functioning?
What implications for a child’s education result from the type
of hearing loss and age of onset?
How do students who are deaf and hard of hearing use
technologies and supports to amplify, supplement, or
replace sound?
How do oral/aural, total communication, and bilingual–
bicultural approaches to educating children who are deaf and
hard of hearing differ in their philosophies and methods?
How might membership in the Deaf culture influence a
student’s and his family’s perspectives and wishes regarding
educational placement?
Heward
Exceptional Children, 10e
© 2013 Pearson Education, Inc. All rights reserved.
9-2
Definitions of Hearing Loss
IDEA Definition
Deafness is a hearing loss that is so severe that the child has
difficulty processing linguistic information and it adversely
affects educational performance
Hearing loss means a loss in hearing that adversely affects
educational performance but that is not included under the
definition of deafness
Deaf: Students use vision as the primary sensory mode for
learning and communication
Hard of hearing: Students use their hearing to understand
speech with the help of a hearing aid
Many persons who are deaf do not view hearing loss as a
disability
Heward
Exceptional Children, 10e
© 2013 Pearson Education, Inc. All rights reserved.
9-3
How We Hear
Audition, the sense of hearing, is a complex
and not completely understood process
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The outer ear consists of the external ear and the auditory
canal
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We see the auricle which funnels sound waves into the
auditory canal and helps distinguish the direction of sound
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Sound waves are slightly amplified as they move toward the
tympanic membrane
•
Variations in sound pressure cause the eardrum to move in
and out
•
The vibrations of the bones of the middle ear transmit energy
to the inner ear
•
The inner ear is the most critical and complex part of the
hearing apparatus
Heward
Exceptional Children, 10e
© 2013 Pearson Education, Inc. All rights reserved.
9-4
The Nature of Sound
Sound is measured in units that describe its intensity and
frequency
• Decibels (dB)
• the intensity or loudness of sound
• Zero dB represents the smallest sound a person with
normal hearing can perceive
• Sounds of 125 dB or louder cause pain to most persons
• Hertz (Hz)
• the frequency or pitch of sound is measured in cycles per
second
• Pure tones consist of one frequency
• The frequency range most important for hearing spoken
language is 500 to 2,000 Hz
Heward
Exceptional Children, 10e
© 2013 Pearson Education, Inc. All rights reserved.
9-5
Characteristics of Students with
Hearing Loss
Students who receive special education because of
hearing loss are a heterogeneous group
Levels of functioning influenced by:
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Type and degree of hearing loss
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Age of onset
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Attitudes of parents and siblings
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Opportunities to acquire a first language
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The presence or absence of other disabilities
Generalizations about how deaf people are supposed
to act and feel must be viewed with extreme caution
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Exceptional Children, 10e
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9-6
Characteristics (cont.)
English Literacy and Speaking Skills
Students with hearing loss
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Have smaller vocabularies than their peers with normal
hearing and the gap widens with age
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Learn concrete words more easily than abstract words
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Have difficulty with function words and omit endings of
words
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Have difficulty differentiating questions from statements
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Have difficulty understanding and writing sentences with
passive voice and relative clauses
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May have atypical speech and are unable to monitor their
own speech
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Exceptional Children, 10e
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9-7
Characteristics (cont.)
Academic Achievement
•
Students with hearing loss have difficulty with all areas of
academic achievement, especially reading and math
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The gap in achievement between children with normal
hearing and those with hearing loss usually widens as they
get older
•
Approximately 30% of deaf students leave school
functionally illiterate
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Academic performance must not be equated with
intelligence
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Problems attributable to inadequate development of a first
language and the mismatch between the demands of
spoken and written English and the students’ ability to
understand and communicate in English
Heward
Exceptional Children, 10e
© 2013 Pearson Education, Inc. All rights reserved.
9-8
Characteristics (cont.)
Social Functioning
•Behavioral
difficulties in school and social situations more
likely in children with hearing loss than children with normal
hearing
•Reports
of feelings of depression, withdrawal, and isolation
frequently reported by children and adults who are deaf with
adventitious hearing loss
•Poor
readers were more likely to exhibit problem behavior in
school according to one study
•The
extent to which a child with hearing loss successfully
interacts depends on others’ attitudes and the child’s ability to
communicate in some mutually acceptable way
Heward
Exceptional Children, 10e
© 2013 Pearson Education, Inc. All rights reserved.
9-9
Prevalence
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The large majority of persons with hearing loss
are adults
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Males are more likely than females to experience
hearing loss
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During the 2009-2010 school year, about 1.2% of
school age children receive special education
services for hearing loss and about 0.1% of the
resident student population
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A national survey indicated that about 41% of
deaf or hard of hearing students had severe or
profound hearing loss and about 40% had
another disabling condition
Heward
Exceptional Children, 10e
© 2013 Pearson Education, Inc. All rights reserved.
9-10
Types of Hearing Loss
Type of hearing loss is determined by the affected
region of the auditory system
Conductive Hearing Loss
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Results from abnormalities or complications of the outer or
middle ear
Sensorineural hearing loss
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Entails damage to the cochlea or involves abnormality or
failure of the auditory pathway
Mixed hearing impairment
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Combination of conductive, sensory, and neural hearing loss
Unilateral hearing loss is present in one ear only
Bilateral hearing loss is present in both ears
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Exceptional Children, 10e
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9-11
Causes of Hearing Loss
Congenital hearing loss is present at birth
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Causes of congenital hearing loss
Genetic Factors
– Maternal Rubella
– Congenital Cytomegalovirus (CMV)
– Premature birth
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Acquired hearing loss appears after birth
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Pre-lingual hearing loss before speech develops
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Post-lingual hearing loss after speech develops
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Causes of acquired hearing loss
Otitis Media
– Meningitis
– Ménière’s Disease
– Noise-induced hearing loss
–
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Exceptional Children, 10e
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9-12
Identification and Assessment
The Joint Committee on Infant Hearing recommend
that all infants be screened by 1 month of age
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Auditory brain stem response
Otoacoustic emission screening
Assessment of Older Children and Adults
Pure-tone audiometry
• Assessed using an audiometer
Speech Reception Test
Alternative Audiometric Techniques
• Play audiometry
• Operant Conditioning Audiometry
• Behavior Observation Audiometry
Heward
Exceptional Children, 10e
© 2013 Pearson Education, Inc. All rights reserved.
9-13
Classification of Hearing Loss
Classification of hearing loss depends on the
average hearing level in decibels across the
frequencies most important for understanding
speech
Slight
Mild
Moderate
Severe
Profound
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Exceptional Children, 10e
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9-14
Technologies That Amplify or
Provide Sound
Hearing aids
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Hearing aids make sounds louder but not necessarily clearer
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The earlier in life a child is fitted the more effectively he will learn to
use hearing
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To derive maximum benefit a hearing aid should be worn
throughout the day
Group assistive listening devices
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A radio link established between the teacher and the child can solve
problems caused by distance and noise
Cochlear implants
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A cochlear implant bypasses damaged hair cells and stimulates the
auditory nerve directly
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Tremendous controversy surrounds cochlear implants in the deaf
community
Heward
Exceptional Children, 10e
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9-15
Supports and Technologies that
Supplement or Replace Sound
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Signing the speech of a teacher of other speaker for a person
who is deaf
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Television, video, and movie captioning
Printed text that appears at the bottom of the screen
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Speech-to-text translation
Computer devices that translate speech to text
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Interpreting
Text telephones
Allows the user to send a typed message over telephone lines
Computer
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Technology
Alerting devices
Heward
Exceptional Children, 10e
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9-16
Educational Approaches
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Oral/Aural Approaches
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Auditory Learning
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Speech reading
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Cued Speech
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Total Communication
Simultaneous presentation of language by a variety of forms
of communication
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American Sign Language (ASL) and the BilingualBicultural Approach
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ASL is a legitimate language in its own right
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The goal of the bilingual-bicultural approach is to help deaf
students become bilingual adults who can read and write with
competence in their second language
Heward
Exceptional Children, 10e
© 2013 Pearson Education, Inc. All rights reserved.
9-17
Educational Placement
Alternatives
Approximately three-fourth of children who are deaf
or hard of hearing attend local public schools
• 60%
receive most of their education in general
education classroom with hearing students
• 10%
attend resource rooms for part of the school
• 17%
are served in special classrooms
• 25%
attend special schools for the deaf
day
About 40% of all students with hearing loss go on to college
education
Heward
Exceptional Children, 10e
© 2013 Pearson Education, Inc. All rights reserved.
9-18