Transcript Hearing disorders of the outer ear

Indications of non-organic hearing loss

Inconsistent behavior and performance on tests.

Poor test-retest reliability
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Incompatibility between PTA and SRT

Acoustic reflexes found at very loss sensation
levels
Tests for non-organic hearing loss

Objective tests:
 Acoustic reflex
 Auditory evoked potentials
 OAE

Behavioral tests:
 Stenger (Most popular)
 Lombard
Stenger test
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Theory: If two sounds of the same frequency are
presented simultaneously to both ears, only the louder
tone will be perceived.
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Used in case of assymetrical hearing loss with at least 25
dB difference between ears.
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Steps

Measure unmasked threshold for both ears separately.
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Present a 10 dB SL tone in better ear: Response
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Present a 10 dB below threshold in poorer ear: No response
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Now, both tones presented simultaneously
Results of Stenger test
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Negative Stenger: If response, then, no non-organic
hearing loss

Positive Stenger: If no response, implies that the tone
was heard in poorer ear but patient unwilling to respond.
Unaware of tone in better ear because of Stenger effect.

Can be done with pure tones and speech.
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Can also be used to approximate real thresholds by
finding the minimum level at which a positive Stenger is
obtained.
Lombard test

Theory: In the presence of background noise, individuals
speak louder.
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Ask patient to read or speak aloud.

Masking noise is added and gradually increased in level.

If patient increases speech level, then masking noise
heard.

Diagnosis of non-organic hearing loss made based on
level of noise and measured thresholds.
Other tests

Varying intensity story test: Present parts of
story above threshold and parts below
threshold, ask questions based on story.

Count the number of tones heard

Yes/No method (for children)