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As well as having a consultation with a patient and
examining them a Doctor will often require various investigations
to make a diagnosis. Please use the menu on the left
to find out some of the common ones with a brief explanation
of their use:-
Hearing tests (Audiometry)
A hearing test is essential in any patient who complains
of hearing loss, dizziness or ringing in the ears (tinnitus).
It is also essential before or after any operation on
the ears. The commonest type of hearing test is a pure
tone audiogram (PTA).
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Pure tone audiogram
The patient is put in a sound proof booth and the noise
is presented to them through headphones and the patient
has to press a button when he hears the sound. Hearing
tests in children are far more complicated and require
a high degree of skill, patience and experience on behalf
of the audiologist, sometimes two audiologists are required
at once. Depending on the age and co operation of the
child the following tests may be required
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Distraction testing.
(6-18 months old)
A toddler with suspected hearing loss can be investigated
by various sounds and their reaction in turning towards
the sounds can give an indication as to the degree of
hearing. Baby must have matured to the stage of being
able to sit erect and perform head turn responses in
the horizontal plane. Two testers are required to undertake
tests, one presenting sound stimuli out of the visual
field and the second tester controlling the baby’s
attention in the forward direction.
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© Visual response
audiometry (VRA)– (8 to 18 months)
The essence of VRA is to reinforce an observable behavioural
response (usually head turning) to frequency specific
sounds with a visual reward. The child’s attention
is attracted by the sound and it turns in order to see
the visual reward. Sufficient trials are give in order
to assess threshold responses to sounds accurately at
a number of different frequencies. Beyond this core,
there may be facilities to assess localisation, to assess
each ear separately using insert earphones or headphones.
Two testers are required to undertake test, one distracting
the child while the other presents the sound stimuli
and activates the visual reward.
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The Co-operative test
(18 – 30 months)
The objective is to develop a giving game with simple
toy material and to record the minimum listening level
required for the comprehension of simple instructions,
such as “give this to teddy”.
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Performance test (2years
6 months – 3years 6 months)
The child is conditioned to wait of an auditory stimuli
and then to respond in a play activity such as placing
a ball on a stick, peg in a board or stacking cubes
or breakers.
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Tympanometry
This is a common test to determine whether there is
fluid (glue ear) within the middle ear.
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Oto acoustic emissions
(OAE)
This is increasingly going to be used as a screening
tool as part of the universal neonatal screening programme.
Brain stem evoked response, an electrical recording
is made of the brain waves as a result of a noise stimulus,
and this could be useful in babies with suspected hearing
loss.
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Endoscopy
The diagnosis of diseases of the ear, nose and throat
has been revolutionised in recent years by the endoscope.
There are two types, 1) rigid endoscope, used for looking
mainly into the nose and sinuses. 2) The flexible endoscope
for looking into the voice box or gullet. Usually the
patient is given an anaesthetic spray so that the procedure,
although not enjoyable, is at least tolerable.
A camera can be put on the end of the endoscope and
the patient shown the exact anatomy and pathology. No
consultation for symptoms of nasal pathology, throat
or voice symptoms is complete without endoscopic examination.
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Allergy testing
The role of allergy in nasal symptoms is increasingly
being recognised and skin prick testing is often employed
to identify which objects the patients must avoid in
order to minimise their exposure to the offending item
and maximise the changes of the success of medical treatment.
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FNA (Fine Needle Aspiration)
This is a technique for obtaining cells for examination
(cytology). Most patients who present with a solid lump
in the neck would benefit from having a small sample
of this taken and looked at under a microscope by a
cytologist. Normally a small needle no larger than that
used to take a blood sample is used to take a few cells
and this will often give a very good idea of what the
nature of the lump is. This will guide the surgeon in
deciding whether to advise the lump be removed or not.
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CT Scan (computerised
tomography)
This is an X.ray scan which can give detailed images
of the head in any plain and indeed three dimentional
reconstructed images. It is an essential pre requisite
for any form of sinus surgery. Some patients find having
this examination slightly claustrophobic and if you
do suffer from claustrophobia it is important that you
mention this to your surgeon.
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MRI (Magnetic Resonance
Imaging)
Works in a different way to the CT scan but also gives
images of the head in any plane. Whereas the CT scan
is good particularly for fine detail of bony structures,
the MRI scan is more useful in looking for soft tissues
of the head or brain. The most common reason for using
an MRI scan would be to investigate somebody with an
unexplained hearing loss.
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Barium Swallow
This is an investigation whereby the patient swallows
a liquid whilst an X.ray is taken. The liquid outlines
the mouth, throat and gullet and will show up any obstruction,
hold up or abnormality.
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Vestibular function
tests
Testing the balance organ is very complicated. Not only
does the labyrinth (inner ear) organ of balance need
to be tested but also the pathways connect it to the
brain and the eyes also have to be investigated. For
this reason usually a battery of tests, which include
observing eye movements, head movements are required.
To directly investigate the inner ear both hot, warm
and cool water are often run into the ear canal to stimulate
the organ and the movement of the eyes caused by this
change in temperature are observed.
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