A diagnostic audiological evaluation is a series of audiological tests performed by an audiologist to determine the health of your auditory system.
What is audiology? This is an excellent description by the Canadian Academy of Audiology https://canadianaudiology.ca/for-the-public/about-audiology/
In order for us to hear, there are several processes that take place before your brain registers that you have heard a sound. A sound wave will enter the ear canal and reach the eardrum which will vibrate. This vibration will send the ossicles (3 tiny bones in your middle ear) into mechanical motion. The last bone in this chain, called the stapes, will pump on the membrane of the cochlea. The cochlea is filled with fluid and this pumping action will send a transverse wave through the cochlea at a specific frequency. This will stimulate the outer hair cells in the cochlea and translate into a nerve impulse that travels up the auditory nerve to the brainstem and then on to the auditory cortex. It is in the auditory cortex where we “process” and “understand” sound. A complete diagnostic hearing evaluation measures the function of the outer, middle, and inner ear. It also assesses the brain’s ability to process complex sounds, such as speech. In order for audiologists to make recommendations on improving your hearing, we must first know where the problem is and whether there is any requirement for further medical investigation.
A complete diagnostic audiological evaluation involves the following tests. Otoscopy is an examination of the ear canal with an otoscope. It allows us to check for wax or debris in your ear canal and to determine the health of your eardrum. Tympanometry usually comes next and is a measure of the middle ear function. We send air pressure into your ear canal to measure the movement of your eardrum to rule out fluid in the middle ear or a perforation in the eardrum. Air conduction testing involves listening to pure tones at specific frequencies. These are the “beeps” that you are likely familiar with if you have had a hearing screening in the past. These beeps translate into specific speech sounds and helps us determine how clearly you are hearing speech. We will also do some speech testing to determine your brain’s ability to process complex sounds. We also do bone-conduction testing which involves listening to the same pure tone beeps but you will be wearing a headband that directly sends the sound to your cochlea. This will help us determine if your hearing loss is coming from the outer/middle ear or the inner ear. We will sometimes measure acoustic reflexes, which are measurable reflexes to loud sounds to determine the integrity of your auditory nerve function.
An initial diagnostic hearing evaluation should include these tests. However, a particular test may be excluded if it is not necessary or contra-indicated.
When you see one of us for a diagnostic hearing evaluation, we will explain each of these tests as we conduct them. We will also provide a thorough explanation of your results after the test is complete. If there is an audiological red flag in your audiogram we will refer you for further medical investigation and send a complete report to your family physician.
It is recommended that anyone over the age of 60 years old have a baseline audiological evaluation.
If you have any questions about having a diagnostic audiological evaluation, please don’t hesitate to contact us.