Transcript Unit 12 Hearing Disorders in Children and Adults

Unit Twelve
Hearing Disorders
in Children and Adults
Copyright © 2008 Delmar. All rights reserved.
Chapter 46
Anatomy and Physiology
of the Hearing Mechanism
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Outer Ear
• Collects, resonates, and directs sound
to the tympanic membrane
• Protects middle ear
• Three structures
– Auricle, ear canal, tympanic membrane
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Tympanic Membrane
• Thin, oval membrane
• Separates ear canal from middle ear
• Vibrates at the rate and magnitude of
the sound waves that reach it
• Seventeen times larger than oval
window in the cochlea
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Middle Ear
• Air-filled chamber
• Extends from tympanic membrane to
oval window
• Contains the ossicular chain
– Malleus, incus, and stapes
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Eustachian Tube
• Leads from middle ear to nasopharynx
• Keeps the middle ear at atmospheric air
pressure
• Typically opens with oral and
swallowing movements
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Inner Ear
• Cochlea
• Vestibular system
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Cochlea
• Contains sensory mechanism of hearing
• Filled with fluid
– Contains 13,000 outer hair cells and 3,500
inner hair cells
– Hair cells attached to nerve fibers
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Cochlea
• Motion of the fluid stimulates the hair
cells
– Send impulses to the auditory nerve (VIII)
• Different hair cells are stimulated by
different sound frequencies
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Vestibular Mechanism
• Contains three semicircular canals
• Responsible for maintaining balance
• Interacts with the visual and
proprioceptive systems
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Auditory Nervous System
• Neural impulses from the cochlea
– Sent to the auditory cortex in the temporal
lobes
• 75 percent of impulses from the right
ear are transmitted to the left
hemisphere
– 25 percent ascend on the same side
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Chapter 47
Types and Causes
of Hearing Impairment
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Hearing Impairments
• Hearing sensitivity impairment
– Reduction in sensitivity of hearing
mechanism
• Auditory nervous system impairment
– Reduction in ability to hear sounds clearly
above the hearing threshold
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Incidence
• 28 million in the United States have
some degree of hearing loss
– 4.6 percent incidence for 18-44 years
– 14 percent incidence for 45-64 years
• I in 1000 infants has severe to profound
hearing loss
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Hearing
Sensitivity Impairments
• Conductive loss
– Due to disorder of outer or middle ear
• Sensorineural loss
– Due to disorder of cochlea
• Mixed loss
– Combination of conductive and
sensorineural
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Hearing Loss and Outer Ear
• Malformed or absent pinna
• Malformed or absent ear canal
• External otitis
– Swimmer’s ear
• Objects or excessive wax in canal
• Perforation of tympanic membrane
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Hearing Loss and Middle Ear
• Otitis media
• Otosclerosis
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Otitis Media with Effusion
• Inflammation and/or infection of mucous
membrane lining middle ear
• Treated with antibiotics
• Surgery with PE tubes if otitis media is
recurrent
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Otosclerosis
• Ossification occurs in ossicles
– Especially the stapes
• Women affected twice as often as men
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Hearing Loss and Inner Ear
• Largest cause of sensorineural
impairments
• Decreased hearing sensitivity
• Difficulty understanding speech
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Noise-Induced Hearing Loss
• Exposure to excessive sound results in
change in threshold of hearing
sensitivity
• Can be temporary or permanent
• Length of exposure is important
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Tinnitus
• A noise sensation
– Ringing, roaring, swishing
• Heard in one or both ears
• May be a sign of otosclerosis
– Ménière's disease
• Can affect concentration, sleep, social
functioning
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Meniere’s Disease
• Disease of inner ear characterized by:
– Vertigo
– Tinnitus
– Sensorineural hearing loss
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Presbycusis
• Progressive hearing loss as a result of
aging
• Difficulty understanding speech
– Especially in background noise
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Communicative Disorders of
Individuals with Hearing Loss
• Variables that affect the type and
degree of communication disorder
include:
– Age
– Severity, configuration, and type of loss
– Beginning of rehabilitation
– Other handicaps
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Speech
• Sounds that are not heard are difficult to
develop
– Final consonants, unstressed sounds
• Stress, rate, breath control, pitch can be
difficult
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Language
• Form
– Primarily content words, omit function
words, telegraphic
• Content
– Weak vocabulary
• Use
– Difficulty with conversations, turn-taking
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Literacy
• Average reading ad writing levels of
deaf high schoolers are at 3rd or 4th
grade level
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Multicultural Considerations
• Across all ethnic and racial groups,
three primary causes of hearing loss:
– Prematurity
– Heredity
– Meningitis
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Chapter 48
Hearing Assessment
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Newborn Hearing Screening
• Now routine procedure in many
hospitals
• Auditory brainstem response
– Records electrical responses of the brain
to sound
• Otoacoustic emissions
– Echoes that occur in response to sound
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Pediatricians and Family Practice
• First professionals to see child with
hearing problems
• Conduct case history and interview
• May perform several tests:
– Weber’s test
– Rinne test
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Audiologist Case
History and Interview
• Audiologist gathers information about:
– Patient and family complaints
– Is loss unilateral/bilateral?
– Acute/chronic?
– Duration of loss
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Pure-Tune Audiometry
• Establish hearing threshold sensitivity
across frequencies
• Audiometers quantify hearing and can
measure air and bone conduction
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Audiograms
• Graphs that record pure tone hearing
thresholds graphed by frequency (Hz)
and hearing level (dB)
• Conventional frequencies tested are
250, 500, 1500, 2000, 3000, 4000, 6000
and 8000 Hz.
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Audiograms
• Indicate degree of loss and effects on
communication
• Indicate audiometric configuration:
– Flat, downward, rising
• Provide a measure of interaural
symmetry
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Masking
• When two sounds occur simultaneously
and one sound is loud enough to cause
the other sound to be inaudible
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Speech Audiometry
• Measures thresholds for speech
• Cross-check on pure tone audiometry
• Quantify above threshold speech
recognition
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Speech Audiometry
• Determine range of comfortable to
uncomfortable loudness
• Recognition and discrimination of
speech sounds
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Electroacoustic and
Electrophysiologic Measures
• Immitance audiometry
– Measures how energy flows through outer
and middle ear
• Tympanometry
– Measures middle ear compliance
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Electroacoustic and
Electrophysiologic Measures
• Electrocochleography
– Measures electrical responses in the
cochlea
• Auditory evoked potential
– Measures electrical activity in the brain
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Multicultural Considerations
• Some auditory disorders are more
common in certain racially and
ethnically diverse populations
– Genetic disorders
– Otitis media
– Presbycusis
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Chapter 49
Amplification and
Aural Rehabilitation
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Amplification for Infants
• Intervention should begin before 6
months
• Team approach is required:
– Audiologists, SLPs, social workers, special
and regular educators, counselors
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Role of the Parents and Family
• Fitting of hearing aids
• Counseling
• Encouragement for development of
communication
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Hearing Aids
• An ongoing process for appropriate
fitting and gain
• Parents need to be involved in care and
daily use
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Components of Hearing Aids
• Microphone
• Amplifier
• Receiver
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Styles of Hearing Aids
•
•
•
•
Behind-the-ear
In-the-ear
In-the-canal
Completely-in-the-canal
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Assistive Listening Devices
• Amplification systems designed for
specific listening situations:
– Personal amplifier
– Telephone amplifier
– Personal FM system
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Other Assistive Devices
•
•
•
•
Closed captions
Vibratory pagers
Vibrating and/or flashing alarm clocks
Doorbell or smoke detector fitted with
lights
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Cochlear Implants
• Appropriate for clients with severe or
profound bilateral hearing loss
• Stimulate auditory nerve directly by
applying electrical currents
• Sounds are not like typical hearing so
post-implant training is required
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Components
of a Cochlear Implant
• Internal
– Receiver and electrode display
• External
– Microphone and amplifier
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Aural Rehabilitation
• Minimizing and alleviating the
communication difficulties associated
with hearing loss
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Auditory Training
• Develop ability to recognize speech
using auditory signals
• Appropriate for children with residual
hearing
• Amplification required before training
begins
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Elements of Auditory Training
•
•
•
•
Detection
Discrimination
Identification
Comprehension
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Lip Reading
• Using visual cues of speaker’s mouth
and face to recognize speech
• Factors that influence lip reading:
– Visibility of sounds, rapidity of speech,
coarticulation, visages, and homophones
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Goals for Speech Development
• Increase vocalizations
• Expand phonetic and phonemic
repertoire
• Increase speech intelligibility
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Therapy Goals
in Language Development
•
•
•
•
Use complex concepts and discourse
Expand vocabulary
Enhance syntax and pragmatics
Develop narrative skills
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Sign Language
• Visual means of communication using
arm and hand shapes
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Multicultural Considerations
• Little information on deaf cultures within
other cultural groups
• “Deaf” community is a genuine culture
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Chapter 50
Emotional and Social
Effects of Hearing Disorders
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Stages of Life
• Impact of hearing loss is affected by
different stages of life
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Newborns
• Families will proceed through the stages
of grief:
– Denial, anger, bargaining, depression,
acceptance
• Stages do not follow a linear pattern
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Infants
• Infant-parent bonding can be affected
• Infant may be unresponsive to parental
verbal play
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Childhood
• Parents may struggle to cope with
hearing loss
• Children may have poorer self-concepts
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Adolescence
• May have poorer peer relationships than
hearing adolescents
• Audiologists can help hard-of-hearing
adolescents connect with one another
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Young Adult and Late Adulthood
• Clients may feel the hearing loss has
come “too soon”
• May have to re-evaluate life expectations
and goals
• May feel they do not fit into any social
group
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Old Age
• Hearing loss can be made more
handicapping by other conditions of old
age
– Vision loss
– Physical impairments
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Emotional and Social Support
• Parent support groups
• Counseling
• Assertiveness training
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Multicultural Considerations
• Deaf culture views deafness as a
difference
– Not a pathology, disorder, or defect that
needs treatment
• Minority groups in the deaf world have a
diversity of values and beliefs
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