Professional Hearing Tests
A hearing test is performed by an audiologist using an audiometer to evaluate a person’s sense of hearing. The hearing efficiency of a person at different frequencies is determined in a hearing test. Prior to a hearing test it is made sure that there are no particles inside the ear which can obstruct sound. There are various different reasons due to which a person may develop hearing loss like genetic disorders, exposure to noise pollution, ageing, birth complications, infections, certain toxins and trauma to the ear.
There are different forms of hearing tests throughout Melbourne like Pure Tone Audiometry, Weber and Rinne, Hearing in Noise and others. Pure Tone Audiometry measures the air and bone conduction thresholds in a set of eight standard frequencies from 250 Hz to 8000 Hz. The test is conducted using a sound booth using a pair of headphones connected to an external audiometer. The result is an audiogram diagram which plots a person’s hearing sensitivity at the various tested frequencies. There is also a high frequency test which is conducted in special circumstances.
To find what kind of hearing loss is present a Webber and Rinne bone conduction hearing test is carried out. A vibrating tuning fork is used and is placed behind the ear of the patient. When a person no longer hears vibration the tuning fork is held in front of the ear. If the person cannot hear a ringing sound then there is conductive hearing loss in the ear. Then the tuning fork is placed on the forehead. The patient is asked where the sound is localised. If there is sensorineural hearing loss then the sound will be quieter in the affected ear. In conductive hearing loss sound is louder. This hearing test determines if a person suffers from conductive, sensorineural or neural problems.
The Hearing in Noise test measures the ability to hear speech in a silent environment and in a noisy environment. In the Hearing, in Noise test a patient in a quite environment is required to repeat sentences. Along with this, there are competing noises being presented from different directions. What the hearing test does is measure the signal to voice ratio for different conditions. It is tested how long the sentences need to be played above the noise so the patient can repeat them correctly fifty percent of the time.
Speech tests may also be conducted where patients repeat the words they hear. A test like tympanogram may be done which indicates how well the eardrum and ossicles are moving. An acoustic reflex test may be performed to have information about the vestibular and facial nerves and to indicate if a lesion may be present.