الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
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English Summary
Functional hearing loss is a term used to describe
hearing disorder with either no organic pathology
or with pathology insufficient to explain the extent
of a hearing loss.
One type of this hearing loss is psychogenic. Such
a patient is not trying to fool anybody, he himself
is convinced that he has hearing loss.
There are a number of signs that alert the audiologist
to functional hearing loss. Some of them are
non-test situations which must be put in consideration.
Others which include performance of routine hearing tests
as pure tone audiometry and speech tone audiometry.
The discrepancy between the SRT and pure tone average
is a main sign of functional hearing loss. Inconsistency
of the results on retesting the patient is also a criterion
of functionality.
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Special diagnostic tests as Doerfler-Stewart,
Stenger, electric response audiometry ... etc. are
also used for further confirmation of the functional
element.
Using the acoustic impedance is of a great help
in the detection of functional patient. The difference
between voluntaryand acoustic reflex levels (SL) is
taken as an indication of functionality, the smaller
the difference the more suspicion. However if the SL
is as small as (12.5 dB) the patient can be diagnosed
as functional.
But if the SL is about 40 dB we have to proceed
to other tests to differentiate between functional and
recriuting patients.
The mere elicitation of the acoustic reflex will
decrease the possibility of the patient having severe
hearing loss.
However, the acoustic impedance method cannot
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be used in cases where the acoustic reflex is lost as
in conductive hearing loss and facial palsy.
Also in some cases the acoustic reflex may be absent,
yet the subject is considered having functional hearing
loss, if he has an organic lesion as well.
Acoustic reflex is a very useful tool in diagnosis
of functional hearing loss but it must be done with
the aid of the whole audiometric battery.