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HKMA Structured CME Programme with HKS&H Session 11 The Child is not Responding to Sounds
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THE CHILD IS NOT
RESPONDING TO
SOUNDS
Dr. Dennis Kin-kwok AU AuD
Audiologist Hearing and Dizziness Laboratory
Hong Kong Sanatorium & Hospital
HEARING LOSS IS AN
INVISIBLE HANDICAP
Warning Signals Hearing Defects (I)
• Risks Factors
• Suspicion on mother's part
• Not responding to nearby or everyday sounds by
6-8 weeks
• Not showing ordinary interest in people and for
play things by 3-4 months
Warning Signals Hearing Defects (II)
• Not using frequent, tuneful, repetitive babble to
self and others by 10 months
• Not speaking single words by 21 months
• Not putting 2 or 3 words together in sentences by
27 months
• Not using fully intelligible speech by 4 years
High Risk Factors (I)
• Family history of deafness
• Congenital deformities, esp. ENT
• Ante-natal viral infections (rubella, cytomegalo
virus)
• Peri-natal and post-natal infections (bacterial
meningitis, syphilis)
High Risk Factors (II)
• Low birth weight < 1500 gm
• Hyperbilirubinaemia (serum bilirubin > 18 mg
percent or exchange transfusion)
• Severe cerebral hypoxia (Apgar score at 5 min
< than 5
• Aminoglycosides given for serious neonatal
infections
Types of Hearing Loss
Conductive Sensorineural
Mixed
Types of Hearing Loss
• Conductive
• Sensorineural
• Mixed
• Functional
Audiogram
• Measurement of
hearing level against
different frequencies
Scale of Hearing Loss
HEARING ASSESSMENTS
Impedance Audiometry
• Middle-ear Test
Tympanogram
• Ear canal volume
• Middle-ear pressure
• Amplitude
Tympanogram
Type A
• Type A
Type C
• Type C
Significant –ve middle-ear pressure
ME pressure > 100 daPa
Normal middle-ear pressure &
compliance
Tympanogram
Type B
• Type B
Type B
Middle-ear fluid Perforated eardrum
BEHAVIOURAL TESTS
Distraction Test
• 3 weeks to 18 months
• Elicit head-turn response
• Test the better ear only
• MCHC for hearing test
Distraction Test
Distraction Test
• /mum/mum/mum/ 250 Hz
• chime bar 500 Hz
• chime 1K Hz
• /sh/ 2K Hz
• /s/ 4K Hz
• high-frequency rattle 6-8 KHz
Auropalpebral Reflex (Eye Blink Reflex)
Visual Reinforcement Audiometry (VRA)
• 16 to 30 months
• Reinforcement of
child's response by
attractive visual
stimulus
• Test the better ear
only
Play Audiometry
• 2 1/2 years old and
above
• More interesting
• Test each individual ear
• Ability to wait
OBJECTIVE TESTS
Otoacoustic Emissions (OAEs)
• Sounds generated from normal outer hair cells
• Response to acoustic stimulation
• Absent when hearing loss >30-40dB
• Testing time in 1-2 minutes
• MCHC for hearing test
OAEs
Transient OAEs Distortion Products
Auditory Brainstem Response (ABR)
• A far field recording of synchronized electric
response from auditory pathway in
response to fast acoustic stimulus
• Diagnostic test
Sedation
• Sedation (choral hydrate) 30 mg/kg
• Natural sleep
Hearing Thresholds
• Look at the presence or absence of Wave V
Hearing Thresholds
• Look at the presence or absence of Wave V
AURAL REHABILITATION
Hearing Aids
BTE mBTE ITE ITC CIC
Hearing Aids CROS Hearing Aid Tactile Hearing Aid
Hearing Aid with Remote Control Eyeglass Hearing Aid
Speech Audiogram
Advantages of Binaural Hearing /
Binaural Hearing Aids • Binaural summation > 3-5 dB
• Better speech discrimination in noise
• Sterophonic effect
• Feeling of balanced hearing
• Better sound localization
Sound Localization
• Interaural time
difference
• Interaural level
difference
Preferential Seating in Classroom
• Good ear facing the teacher
• Good view of teacher’s face
• Sit in the front of classroom
• Seated away from source of environmental noise
Cochlear Implant
Cochlear Implant – How it works?
Cochlear Implant Nucleus Advanced Bionic Med El
Selection Criteria for Children (I)
• Bilateral severe to profound deafness
• As soon as possible > 6 months
• No radiological contraindications
• No medical contraindications
Selection Criteria for Children (II)
• Little or no benefit from hearing aids
• Educational program with a strong
auditory/oral component
• Appropriate family expectations and
support
Multidisciplinary Team Approach
• Audiologists
• ENT doctors
• Speech pathologists
• Social workers
• Teachers of the deaf
• Linguist
• Administrators
Mapping of Speech Processor
• Measure threshold
level (T)
• Measure comfortable
level (C)
• Determine if any
electrode stimulation
causes, pain,
dizziness, irritation,
inconsistent percept
Microtic / Atresic Ears
Bone Anchored Hearing Aid (BAHA)
• Made up of three
parts
• Fixture
• Abutment
• Sound Processor
Bone Anchored Hearing Aid (BAHA)
• Sounds are picked up by the speech processor
• Sounds are transmitted through bone conduction to
cochlear/s
Indications
• Single Sided Deafness
• Chronic otitis media
• Congenital atresia
Patients suffering from conductive, mixed or unilateral hearing loss due to
BAHA
Vibrant Bonebridge
Vibrant Bonebridge – How it works?