Diagnostic Hearing Assessments – Full age spectrum
Diagnostic hearing assessments can be conducted on patients of all ages. The patient is seated in a large soundproof booth during testing to ensure accurate test results. Using a variety of clinical tools, which should consist of pure-tone testing (Air and Bone conduction), speech audiometry and impedance testing, the audiologist will determine the presence or absense of a hearing loss, the sevrity thereof and the nature of the loss. Based on these findings the audiologist can make a recommendation on further management.
Auditory Brainstem Response Testing
An Auditory Brainstem Response (ABR) test is an objective test (i.e. no behavioural responses required) that can be used to estimate hearing sensitivity and to identify neurological abnormalities of the auditory nerve and the auditory pathway up through the brainstem. In other words it measures the reaction of the parts of the patient’s nervous system that affect hearing or how the individual parts respond to sound stimuli. This test is mostly conducted on babies or in cases where a hearing loss is suspected but cannot be confirmed through more conventional hearing assessments.
An ABR test can only be completed if the patient is sleeping or lying perfectly still, relaxed and with his or her eyes closed. This can be conducted with or without sedation depending on the patient’s age. Four small stickers called “electrodes” will be placed on the patient’s head and in front of his or her ears and connected to a computer. As sounds are made through the earphones, the electrodes measure how the patient’s hearing nerves respond to them.
The audiologist, looks for certain neurological “markers” as the patient’s hearing nerves respond to sounds. The softest intensity or loudness level at which these markers appear roughly corresponds to the patient’s hearing level in that frequency range or pitch. By reading a computer printout of the responses and interpreting these markers, the audiologist can tell if the patient presents with a hearing loss or not.