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Introduction to Audiology
Ed Brown
Consultant Clinical Scientist (Audiology)
South of Tyne NHSP Local Director
Royal Hospital
Sunderland
SR4 7TP
0191 569 9001
[email protected]
Audiology
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Newborn Hearing Screening
Paediatric Screening
Paediatric Hearing Assessment
Adult Diagnostic Testing
Hearing Aid Provision
Bone Anchored Hearing Aid Provision
Adult Rehabilitation
Hearing Therapy
Tinnitus Rehabilitation
Balance Assessment
Balance Rehabilitation
Auditory Implants (including Cochlea Implants)
Measurement of Hearing
School-age children and adults can have their hearing
assessed by audiometry
Pure tone sounds are presented through headphones
Frequencies from 250-8000 Hz are typically tested
Threshold is found at each frequency in dB HL
Results (dB HL versus frequency) are plotted on an
Audiogram
Audiometry
Low pitched humming
Very Quiet
Normal Conversational Voice
Mild
Moderate
Severe
Very Loud
High pitched whistling
Profound
Anatomy & Physiology
Types of Hearing Loss
There are two main types of hearing Loss:
Anything which prevents or reduces the
vibrations through the external or middle ears
will produce a conductive deafness
If the cochlea or nerve is affected it will result
in a sensorineural deafness
Conductive Hearing Loss (CHL)
Typical CHL Audiogram
CHL Summary
Due to an abnormality in middle or outer ear
Ear canal completely blocked with wax
Fluid in the middle ear cavity “glue ear”
Chronic middle ear disease
Abnormality in the middle ear bones (e.g. otosclerosis)
Trauma (things stuck in the ear)
 Incidence is high (quite common)
over 4 out of 5 children may have an episode
 Management can be conservative or surgical
e.g. grommet insertion
Sensorineural Hearing Loss (SNHL)
Typical SNHL Audiogram
Sensorineural Hearing Loss
Sensorineural hearing loss is caused by a problem in
the cochlea (because the hair cells of the cochlea are
not working properly) or with the hearing nerve.
Sensorineural hearing loss is permanent
Generally a child with sensorineural hearing loss will
use amplification (hearing aids and/or a cochlear
implant)
Causes of SNHL
Inherited (genetic) even with no previous family
history of deafness
Syndromic
Congenital Infection (eg CMV)
Ototoxic medication
Severe jaundice
Lack of oxygen at birth
Meningitis
SNHL Summary
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Due to an abnormality in cochlea/ auditory nerve
Can be present at (or shortly after) birth
 Can be acquired (e.g. meningitis)
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Incidence is very low (it is quite rare)
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Approximately 1.3 per 1000 live births - 0.1%
Management is early provision of amplification
Early detection is therefore essential
 Better outcomes if identified < 6 months
 That’s why we’re doing NHSP !
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Newborn Hearing Screening
NHSP Follow Up Assessment
First Appointment within 28 days of referral
Up to 120 minute appointment
Tone Pip ABR (e.g. 1 & 4 kHz)
Tells us more about hearing across pitches
Bone Conduction ABR
Can help identify Conductive versus SNHL
Tests for other conditions
Auditory Neuropathy Spectrum Disorder
Tympanometry
Can help identify OME (Glue Ear)
NHSP Follow Up Assessment
Diagnostic Assessment by 6 weeks of age
Identify if there is a hearing impairment
Conductive or Sensorineural
Mild, Moderate, Severe or Profound
Results to Parents, GP, Link HV, Child Health, SALT,
Paediatrics, (Education/Sensory Support)
Provide appropriate habilitation
Amplification (Hearing Aids)
Family Friendly Approach
Links with Education/Early Support
As soon as appropriate (typically by 6 months of age)
Newborn Hearing Assessment
Oto Acoustic Emissions (OAE)
Transient Evoked OAE (TEOAE) most common
Emission elicited by brief acoustic stimuli (click)
Response 4 to 15 ms after the stimulus (“echo”)
Present in almost all normal ears
Response is abolished if hearing loss > 25 dB HL
Quick and non-invasive
Does not provide threshold information
Only indicates healthy hair cell population
Use includes neonatal screening (well babies)
Equipment (AOAE/AABR)
Auditory Brainstem Response
Objective test of hearing
Assesses function of cochlea and auditory nerve
Does not assess higher auditory function
Use Tone-Pip (Frequency Specific) sounds
1 kHz (low pitch) and 4 kHz (high pitch)
Use Bone Conduction
Identify SNHL versus CHL
Auditory Neuropathy Spectrum Disorder
(OAE/CM present ABR absent/abnormal)
Assessing hearing in newborn babies
ABR Waveforms
Children’s Hearing Assessment
Visual Reinforcement Audiometry(VRA)
Children aged 6 to 30 months (or older)
Child sits erect on the parent's knee facing forward
Front distracter engages child in simple play activity
Sounds through loudspeaker system
Warble tone or narrow band noise employed
Frequencies in the range 0.25-4.0 kHz are tested
Child conditioned to respond when sound heard
Visual reward (animated toy)
Once conditioned then test procedure begins
Levels decreased to find "minimum response"
=< 25 dBnHL consistent with (near) normal hearing
Visual Reinforcement Audiometry
(Age 5 months to 2 Years)
Performance/Play Audiometry(age 2
years to 4 years)
Tympanometry
Otoscopy
 use otoscope to visualise ear drum
 Identify contraindications for tympanometry
 Tympanometry
 probe placed in child’s ear
 assesses middle ear function
 assesses mobility of ear drum
 can help to identify Otitis Media with Effusion
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Tympanometry Assesses
Middle Ear Function
Typical Tympanogram
ECV
MEP
MEC
Normal Range Shown
= 0.9 ml ECV Baseline Adjusted
= -70 DaPa
= 1.1 ml
= normal
Glue Ear
Normal
Glue
Thick Glue
Other Conditions
Normal
Otosclerosis
Perforation
Children’s Hearing Aid Provision
Hearing Aids
High Quality Digital Instruments
 Wide Dynamic Range Compression
 Quiet sounds amplified more
 Loud sound amplified less
 Speech presented at comfortable level
 Reduces need for volume control
 Fitted using a prescriptive approach
 Desired Sensation Level 5.0
 Real Ear Measurement
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Children’s Hearing Aid Provision
Hearing Aids
Technology
Connectivity
Outcomes
Hearing vs Hearing Impaired
Balance Assessment & Rehabilitation
Balance System
Balance Assessment
Assessment of Visual Pathways
Vestibular Myogenic Evoked
Potentials
Balance Rehabilitation
Balance Rehabilitation
Auditory Implants
Cochlear Implant
Bone Anchored Hearing Aid