Hearing Tests
A hearing test is an evaluation of the sensitivity of a person’s sense of hearing, most often performed
by an audiologist using an audiometer. Audiologists are the only healthy professionals with extensive
training on the anatomy and physiology of hearing, and are the only health professionals certified to
perform diagnostic hearing tests. It is used to determine a person’s hearing sensitivity at different
frequencies. There are other hearing tests as well, e.g. Weber test and Rinne test.
Audiometer
An audiometer hearing test is usually administered to a person by having them sit in a soundproof
booth with a set of headphones over the ears or small foam insert earphones placed in the ears,
which is connected to an audiometer. The audiometer produces tones at specific frequencies and set
levels to each ear independently. The audiologist plots the loudness (in decibels) on an audiogram.
The person having their hearing tested will convey that they have heard the tone by either raising their
hand or pressing a button. As the test progresses, the audiologist plots points on a graph where the
frequency is on the x-axis and the loudness on the y-axis. Once each frequency of normal hearing ability
is tested and plotted the points are joined by a line so that one can see at a glance the frequencies a
person is not hearing normally and to what degree the hearing loss is. Normal hearing at any frequency
is a threshold of 20dBSPL or quieter, with worsening hearing the number increases.
Weber and Rinne Tests
A complete hearing evaluation involves several other tests as well. In order to determine what kind of
hearing loss is present, a bone conduction hearing tests is administered. In this test, a vibrating tuning
fork is placed behind the ear, on the mastoid process. When the patient can no longer feel/hear the
vibration, the tuning fork is held in front of the ear; the patient should once more be able to hear a
ringing sound. If they cannot, there is conductive deafness in that ear. Additionally, the tuning fork
is placed on the forehead. The patient is then asked if the sound is localized in the centre of their
head or whether it is louder in either ear. If there is conductive hearing loss, it is likely to be
louder in the affected ear; if there is sensoneural hearing loss, it will be quieter in the affected ear.
This test helps the audiologist determine whether the hearing loss is conductive (caused by problems in
the outer or middle ear) or sensorineural (caused by problems in the cochlea, the sensory organ or hearing)
or neural- caused by a problem in the auditory nerve or auditory pathways/cortex of the brain.
Other Hearing Tests
- The audiologist may also conduct speech tests, whereby the patient repeats the words he or she
hears.
- In addition, the test called a tympanogram is generally done. In this test, a small probe is
placed in the ear and the air pressure in the ear canal is varied. This test tells the audiologist
how well the eardrum and other structures in the middle ear are working, the ear canal volume indicates
if a perforation in the eardrum (tympanic membrane) is present, the middle ear pressure indicates if any
fluid is present in the middle ear space (also called "glue ear" or "otitis media with effusion") and the
compliance measurement indicates how well the ear drum and ossicles (3 ear bones) are moving.
- The last test the audiologist may perform in an acoustic reflex test. In this test a probe is
placed in the ear and a loud (greater than 70 dBSPL) tone is produced. The test measures the reflesive
contraction of the stapedius muscle, which is important in protecting the ear from loud noises, such as
a person’s own speech which may be 90dBSPL at the eardrum. This test can be used to estimate the hearing
thresholds in patients that are unable to perform normal pure tone audiometry and can also give
information about the vestibular and facial nerves and indicate if a lesion is present.
Please read the following articles to learn more about hearing aids:
What is a hearing aid and how can it help me?
Styles of Hearing Aids
What questions should I ask before buying a hearing aid?
How can I adjust to my hearing aid?
How can I care for my hearing aid?
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