Transcript Hearing loss and audiograms

Hearing loss and
audiograms
Objectives
To understand how hearing loss is measured
To recognise the degree and type of deafness from an audiogram
To relate a person’s audiogram to how they might understand
speech
Relevant for: Assignment 1 b Audiology and aural rehabilitation
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Referral pathways in NHS
Over 55
• G.P examines outer ear with
otoscope
• If nothing abnormal detected
(NAD), G.P refers direct to
audiology department for
hearing test (if only agerelated) or to ‘Any Qualified
Provider’ (AQP)
• Hearing aids if appropriate
Under 55 - or over 55 and
needs further examination
• G.P examines outer ear with
otoscope and refers to hospital
ENT (ear, nose and throat)
Consultant
• ENT Consultant examines
outer ear, takes a history,
sends patient to audiology
• Audiology department does
hearing test and further
diagnostic tests if required.
• Hearing aids if appropriate
•
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What is Any Qualified Provider - AQP?
• Patients can choose from a range of providers to get NHS hearing
aids e.g. local hospital or Specsavers, Boots etc.
• Prices paid to providers are determined by the NHS..
• Patients choose based on individual preferences and money will
follow patients’ choices.
• Providers must pass a standard qualification process to ensure they
meet the appropriate quality standards
However, about 20%* of the patients meeting AQP criteria will
have complex needs and so require referral back
*Source: Reading Health Forum
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Pure tone audiometry (PTA)
Uses ‘pure tones’ = tones of a single frequency
Measures the ‘hearing threshold‘ = the quietist sounds
the person can hear
Results are used to help diagnose the type and degree of
hearing loss
Results can be used to prescribe hearing aid(s)
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Ways of classifying the degree of hearing loss
Hearing loss is classified as:
Normal
Mild hearing loss
Moderate hearing loss
Severe hearing loss
Profound hearing loss
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Degrees of hearing loss
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The ‘speech banana’
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The higher the line = the better the hearing
normal
severe
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mild
profound
moderate
Remember how we hear?
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Pure tone audiometry (PTA)
Measuring the ‘hearing threshold‘ using pure tones
at different frequencies
- air conduction
- bone conduction
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PTA air conduction test
Pure tones presented through headphones
Measures the hearing from the outer ear, through the middle ear
to the cochlea
i.e. tests the whole hearing mechanism
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PTA bone conduction test
Pure tones presented through a receiver placed behind the ear
on the mastoid process (bone)
Bypasses the outer ear and the middle ear; sound goes to the
cochlea through the skull
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Why consonants matter…
A__
__u_e___
__o_o_a_e
(vowels only)
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_i_e
_i__ui__
Why consonants matter…
_ ll
st_ d_ nts
ch_c_l_t_
l_k_
b_sc__ts
(consonants only)
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The ‘speech banana’
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Presbyacusis
( Age-related hearing loss)
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Noise-induced hearing loss
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The cochlea
Different frequencies detected in different parts
High frequencies detected nearest to the end where the stapes joins
Excessive noise damages this part
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Descriptors of hearing loss
Sensori-neural
Bilateral
Conductive
Unilateral
Mixed
Symmetrical
Asymmetrical
Congenital
High frequency
Acquired
Low frequency
Progressive
Fluctuating
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