HKMA Structured CME Programme with HKS&H Session 11 The Child is not Responding to Sounds

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?