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).
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.
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.
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.
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”.
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.
This is a common test to determine whether there is fluid (glue ear) within the middle ear.
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.
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.
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.
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.
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.
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.
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.
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.