The method that will be used during a diagnostic hearing evaluation will depend on the age of the individual. It is a good idea to make sure that your ear canals are clean before a hearing test. Earwax can affect the results and make the results unreliable.
Firstly a case history will be obtained and an otoscopic examination will be performed. After these procedures, audiometry will be done.
Normally pure tone audiometry will be performed on any individual older than seven years. This will entail that the patient be seated in a soundproof room (if the testing is being done in our offices), earphones will be placed on his or her head and soft sounds of different pitches will then be presented.
The patient is then requested to press a button every time he or she hears the sound (even if it is very, very soft). Adaptations of this technique may occur for example to say ‘Yes’ every time a sound is presented or for the younger population, to catch a bird/butterfly, when they hear the sound.
This presentation of sound through the ear phones will determine the patient’s hearing threshold over the frequency regions 125 Hz to 8000Hz, as well as monitor for the presence of any middle ear pathology.
After threshold determination through the ear phones, the functioning of the patient’s hearing nerve should also be assessed. This is done through the placement of a bone conductor on the bony protrusion behind the ear or on the forehead of the patient. The same procedure is then followed where the patient must indicate when they hear a just audible sound.
These tests will be adapted based on the age and concentration level of the patient and for certain age groups, visual response audiometry and play audiometry will be performed.
Visual response audiometry is based on the premises that developing infants normally will turn towards a sound source. This response to sound provides an opportunity to evaluate a child’s hearing abilities. With this behavioural evaluation a sound is presented and immediately followed with an interesting visual event or reinforcer, such as an animated toy.
The results obtained with these tests are indicated on an audiogram. It is important to keep in mind that any individual hear sounds of different pitches or frequencies. This means that somebody might have a hearing loss in certain frequencies and normal hearing abilities in other frequencies.
After pure tone audiometry involving air conduction and bone conduction, speech audiometry should ideally be performed. This entails that words are being presented to the patient which he or she should then repeat back. It is important to take note of the fact that the aim of some of these tests are not always to hear 100% of the words correct, but sometimes the aim is only to obtain 50%!
This test is also adapted for the younger population where they are asked to show body parts or by showing to pictures.
The results of all the tests performed on an individual should correlate with one another to ensure that valid and reliable results were obtained for diagnosis.