Diagnostic Audiologic Evaluation
A full diagnostic audiologic evaluation is comprised of a variety of testing performed by an audiologist to determine if a hearing loss is present and, if so, to detail the type, severity, and origin of the hearing loss. This information provides guidance for our audiologist, Dr. Casey Polcari, in making appropriate treatment recommendations or referrals to other professionals.
The specific testing performed during the evaluation will depend on the patient's age, symptoms and medical history. These various tests will determine the degree of hearing loss, the type of hearing loss, and the conditions of the ear canal and middle ear. The audiologist will also establish if the hearing loss is conductive (middle or outer ear problem) or sensorineural (inner ear problem or an issue with the auditory nerve and central auditory pathways).
A common audiologic evaluation includes otoscopy, tympanometry, pure tone testing, and speech testing.
Otoscopy and tympanometry
Otoscopy is simply when a doctor uses an otoscope to look into the ear. This allows us to examine the physical condition of the outer ear, ear canal, and eardrum.
Tympanometry is a test which is used to determine the health of the middle ear system. When a doctor looks in your ear, they can only see up the eardrum. Behind the eardrum we have three little bones that move and connect to our inner ear. Tympanometry introduces mild pressure to the ear canal, which in turn moves the eardrum and middle ear bones much like sound does. The results of this test allows us to determine if sound is moving through our auditory system properly, or if, for example, there is fluid in the middle ear space preventing sounds from being heard.
Pure-tone air and bone conduction testing
This is the testing that determines at what decibel level you hear specific frequencies (pitches), from very low deep (bass) tones to high squeaky tones.
Air conduction testing is when headphones are used to introduce the tones to your ears. With air condition testing, sound travels through the entire auditory system, from the outer ear all the way up to the brain. This is how we hear sounds all around us in our day to day lives.
Bone conduction testing is when a different headset is used to introduce tones to the inner ear. A bone conductor is a headset that is placed on the mastoid bone (the bone directly behind the outer ear). Bone conductors use vibrations to stimulate the auditory system. Because this test stimulates the inner ear, outer or middle ear issues are bypassed. This allows us to determine whether the hearing loss is conductive or sensorineural in nature.
There are two speech tests used in routine audiologic evaluations.
A speech reception threshold (SRT) test is used to determine the softest level at which you can make out words. During SRT testing, you will be asked to repeat specific words as the volume decreases. The point at which you can no longer hear the words clearly is your SRT.
Speech recognition scores (SRS) is a test that is used to determine the clarity of speech. A common side effect of hearing loss, especially when left untreated, is the loss ability to hear speech clearly, no matter how loud the speech is. SRS testing is when the audiologist reads a specific set of words and asks you to repeat what you hear. The amount of words heard and repeated correctly is your SRS score. The higher the SRS, the better the ear is at understanding speech.
When hearing loss is left untreated, SRS scores decline. This is because the brain slowly looses the ability to process information that it doesn’t receive. Wearing amplification (hearing aids) keeps the brain active and is the best way to keep your speech intelligibility (ability to understand words).
Specialized tests exist for infants and young children, as well as children and adults with developmental and cognitive impairments. These more specialized tests allow an audiologist to test the auditory system when the patient is not able to actively participate in the tests or evaluation.
What can I expect during a diagnostic hearing evaluation?
The evaluation will last about 30 minutes in length. You should also allow time for discussion with the audiologist to review test results and ask questions.
If the results indicate you need hearing aids, a hearing aid consult will be recommended.
It is advised that you bring a family member with you to the evaluation appointment. Most audiologists agree that hearing loss is a family issue. It helps to have another supportive person at the appointment to help you understand the information and recommendations.
The diagnostic audiologic evaluation is a good chance to establish a relationship with your audiologist. It helps to ask around for recommendations to audiologists in your area and find someone who listens carefully to your concerns. Above all, don't be afraid to ask questions. You will want to be clear on any information you receive so that you can be an active participant in finding hearing solutions that work best for you and your lifestyle.