Audiological tests are essential tools used by audiologists to assess the health and function of an individual’s hearing. They help to identify hearing loss, determine its degree, and figure out the cause. These tests can range from basic screenings to comprehensive diagnostic evaluations, depending on the symptoms and concerns of the individual. Understanding these tests and their results is crucial for anyone who suspects hearing loss or wants to monitor their auditory health.
In this article, we will explore various types of audiological tests and how to interpret the results.
Types of Audiological Tests
Several audiological tests are used to measure hearing function, each targeting different aspects of auditory health. Below are some common tests used in hearing evaluations.
Pure-Tone Audiometry
Pure-tone audiometry is one of the most common tests used in audiology. During this test, you’ll wear headphones or insert earphones, and be asked to listen to various pure tones at different pitches and volumes. The goal is to determine the softest sound you can hear at each frequency. The results are plotted on an audiogram, which is a graph that shows the quietest sound you can hear at various frequencies (measured in Hertz, Hz) in each ear.
In the results, frequencies are displayed along the horizontal axis, and hearing levels (loudness) are shown on the vertical axis. This test helps determine the presence and degree of hearing loss, such as whether the loss is in the high or low-frequency range, and whether it affects one or both ears.
Speech Audiometry
Speech audiometry tests the ability to hear and understand speech. The audiologist will present words at different volume levels, and you will be asked to repeat them. This test evaluates both speech reception thresholds (the quietest level at which you can hear speech) and speech discrimination (how clearly you can understand speech when it’s loud enough to hear).
Speech audiometry helps determine how hearing loss may impact communication. For instance, if a person can hear a sound but cannot understand speech, they may have a different type of hearing issue than someone who has difficulty hearing sounds at all.
Tympanometry
Tympanometry is a test that evaluates the movement of the eardrum in response to changes in air pressure. This test is used to assess the middle ear, and is helpful in diagnosing conditions like fluid in the middle ear, ear infections, or eustachian tube dysfunction. A small probe is placed in the ear canal, and air pressure is varied. The audiologist observes how the eardrum moves in response to pressure changes.
If the eardrum moves normally, it suggests that the middle ear is healthy. However, if the eardrum doesn’t move properly, it could indicate an issue such as fluid buildup, ear infection, or a perforated eardrum.
Otoacoustic Emissions (OAE)
Otoacoustic emissions are sounds generated by the inner ear in response to a stimulus. These sounds are recorded using a small microphone placed in the ear canal. OAE testing is often used for newborn hearing screenings and to assess the health of the cochlea, particularly the outer hair cells.
The test is painless and quick, and its results can indicate whether there is damage to the inner ear. If OAEs are absent or abnormal, it may suggest sensorineural hearing loss. However, a normal OAE result doesn’t always guarantee perfect hearing, as it only assesses the cochlea’s function, not the entire auditory system.
Auditory Brainstem Response (ABR)
The auditory brainstem response (ABR) test evaluates the functioning of the auditory nerve and brainstem. Electrodes are placed on the scalp and earlobes to measure the electrical responses that occur when sound is played through earphones. ABR tests are particularly useful for identifying hearing issues in newborns or individuals who cannot communicate during testing, as well as for diagnosing issues with the auditory nerve or brainstem.
This test can detect hearing loss and auditory pathway disorders and is often used for detecting hearing loss in infants or as a diagnostic tool for unexplained hearing loss in adults.
Understanding the Results of Audiological Tests
Once the tests have been performed, the results are analyzed to determine the presence, type, and degree of hearing loss. Let’s break down how these results are interpreted:
Types of Hearing Loss
Audiologists use the results of the tests to identify the type of hearing loss, which can be one of the following:
Sensorineural Hearing Loss (SNHL): This occurs when there is damage to the inner ear or auditory nerve. It is often permanent and can affect both the clarity and volume of sound. SNHL is typically detected by pure-tone audiometry and speech audiometry.
Conductive Hearing Loss: This type of loss occurs when sound cannot reach the inner ear properly due to issues in the outer or middle ear, such as ear infections, fluid, or a blockage. Tympanometry is commonly used to detect conductive hearing loss.
Mixed Hearing Loss: This is a combination of both sensorineural and conductive hearing loss. The results of various tests, including pure-tone audiometry and tympanometry, can help diagnose this type.
Watch the video above to learn more about audiological tests!
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