What is the difference between a hearing test and an auditory processing assessment?
A hearing test undertaken by an audiologist assesses the functions of the ear, including the cochlear and tympanic membrane.
Auditory processing assessments undertaken by trained clinicians test the brain’s ability to process, store and assign meaning to the auditory signals received by the ear.
The audiology assessment
To understand the process of undertaking an audiology assessment, participate with Shelby as she experiences a ‘hearing test’ administered by Dr Yazdaneh Galt at ACE Audiology & Hearing in Melbourne.
Ace Audiology is located at Shop 29, Bulleen Plaza Shopping Centre
103 Manningham Road, Bulleen, 3105 (next to the inside Post Office)
T: 03 9850 8888
Time: 45-60 mins
Referral: Not necessary
Step 1 – The Interview
The interview involved a series of questions about my general hearing history. I was asked questions like – “Have you experienced fluid or ear infections in your ears as a child? Have you ever had grommets? What is your hearing acuity generally like?” I am a young adult.
Step 2 –Video Otoscopy
The next step was to have a quick look inside my ears. The experience was very comfortable, although I must admit that I have sourced a picture from the internet as my ears were too waxy for me to be comfortable publishing them online! Audiologist Yazdanah Galt is equipped to remove accumulated earwax via either suction, wax rings or syringing should this be required.
Step 3 – Removal of Wax
Now, while this entire appointment was absolutely painless and very comfortable (for the most part) I must admit that having wax removed from my ears is a unique sensation. The first thing you should know is that this process is only needed in 5% of cases and that it is highly unusual for young children to have earwax removed.
Did you know our ears already have a natural system for cleaning themselves? As our inner-ear skin grows, it actually moves sideways so that any dirt or dead skin cells living in our ears are pushed out. Therefore, Cleaning your ears with a cotton bud can be counter-productive as it forces the dirt/wax back into the ear. It is also possible for this seemingly harmless habit to lead to more serious conditions such as a blockage, bacterial infections or a perforated eardrum.
Step 4- Audiogram
When we hear sound, our ears pick it up through air and bone conduction. Audiologists have clients to sit in a sound proof booth with specialized headphones to undertake this test. Inside the booth was very quiet, padded and comfortable with a large glass panel built in so that I could communicate with Yazdaneh while I was inside.
Sitting in this booth reminded me of my younger undergraduate days sitting as a young singer in a recording booth, waiting to hear the music begin. However, instead of listening for music,I was required to wear specialized headphones from which I could hear different tones or frequencies of sound at varying levels of loudness, independently in my right or left ear, and then through bone conduction. The headphones to measure my hearing acuity via bone was different, and they were placed behind my ears so that the tones could go through the bone via vibration.
The second part of this test required me to repeat a variety of words so that my ability to hear and reproduce what I heard could be analysed for pattern errors and to correlate with the audiogram.
Step 5 – Tympanometry Test / Middle Ear Analysis
By controlling the pressure within the ear canal, and recording the reflected sound energy, inferences can be made in regard to the mobility of the tympanic membrane and the status of the middle ear, informing the integrity of the middle ear is present which may require medical treatment.
Yazdaneh explained to me that a Tympanometry test is designed to examine the condition of the middle ear by testing its mobility or “compliance”. This process is essential in diagnosing blockage issues such as ‘Glue Ear’ or retraction of the ear drum. In young children it will demonstrate whether fluid is present which can impact hearing acuity and thus language development.
The process involved inserting a soft ear-bud device into my ear felt no different listening to music with a set of earpieces. The sensation was familiar, with only a slight moment of pressure equivalent to that of being just 20 cm underwater. It is also a necessary preliminary test should acoustic reflex testing be considered appropriate.
Step 6 – Otoacoustic Emission Test
While some children may appear to have ‘normal hearing’, it is still possible that certain sound frequencies may be missing from that spectrum. The Otoacoustic Emissions Test allows audiologists to delve a little deeper by examining the quality of the outer hair cells required to detect sound. While many audiologists do not offer this service, ACE audiology does provide this test to further evaluate hearing in the individual, and is offered as part of a standard hearing test providing a deeper understanding of a client’s ability to hear.
What did the Otoacoustic Emission Test feel like?
Again, the experience was very comfortable. ‘Clicking’ noises were played into my ear for a period of approximately 5-10seconds. The sounds were not dissimilar from what you would imagine the voice of a young robot to be. I found the experience to be rather comical. A chart shows the input tones and distortion product output in real time, providing an extraordinary level of detail.
How does the test work?
Testing otoacoustic emissions involves sending a ‘click’ sound into the ear. The click comprises of a range of frequencies.
There are two main types of otoacoustic emissions tests:
1. Click-evoked Otoacoustic Emissions, and
2. Distortion Production Otoacoustic Emissions (used more commonly).
The otoacoustic machine emits the ‘click’ into the ear canal and then has a microphone to pick up the echo that is received back from the cochlea. It does this as many as 200 times before calculating an average emission amount. This process measures the health of the outer-hair cells of the cochlea.
Audiology Assessment Test
In addition to understanding a client’s ability to identify specific frequencies, the compliment of tests provides extensive information in relation to basic speech processing, acoustic pathways, middle ear status and outer hair cell health.
Test Results & Additional Education Information
Yazdaneh arranged for a comprehensive report to be prepared that summarized the test results. In my case my hearing was normal however, I need to look after my hearing as it can degrade with exposure to loud noise/sound and aging.