An audiometry exam tests how well your hearing functions. It tests both the intensity and the tone of sounds, balance issues, and other issues related to the function of the inner ear. A doctor who specializes in diagnosing and treating hearing loss called an audiologist administers the test.
The test is divided into tonal and verbal audiometry.
In tonal audiometry, the airway and the bone pathway are evaluated, in both cases, the two ears are explored separately and the patient is inside a soundproof and hermetically closed cabin. In aerial audiometry, the person must put on headphones and then play a series of sounds from high to low volume until the expert can be heard. The final perceived sound determines the auditory input, that is, the patient can hear at any intensity at a certain frequency. When examining the bone pathway, a vibrator is placed behind the patient’s ear, at the mastoid, where it receives the sound.
Verbal audiometry is also performed with the patient in the booth and with headphones, but instead of sound, the words are delivered in different volumes, which must be repeated exactly. A word recognition test is also performed, which measures the patient’s ability to distinguish between speech and background noise.
The acoustic reflex test is used to find out where the hearing loss is.
Types of audiometry
Pure Tone Audiometry – This is a very common hearing test. With a pair of headphones, sounds are passed through your outer and middle ears to test hearing sensitivity.
- Bone conduction audiometry – Similar to the pure tone audiometry test, but instead of headphones, a small device is placed behind the ear or on the forehead. Sensitive vibrations are sent through the bone to the inner ear to know how well you are hearing. It also tells you if you have a problem with your router or middle ear.
- Speech Audiometry: This test can help identify neurological types of hearing loss. The auditory system is evaluated by evaluating hearing ability. An audiologist speaks through headphones and the listener must repeat them.
- Upper Threshold Audiometry – Similar to speech audiometry, it is a speech recognition test. It helps to identify different types of hearing loss in both ears by testing whether the listener can accurately recognize speech at the level of distinctive speech.
- Self-recording audiometry (BKC audiometry): the listener can control the rise and fall of the intensity as the frequency gradually changes back and forth across the hearing limit.
- Impedance Audiometry: the measurement of the movement and air pressure of the middle ear system and its reactions.
- Computer Managed Audiometry (Microprocessor): Advanced version of self-recording audiometry.
- Objective Audiometry: This test helps determine if there is any damage to the inner ear. The listener does not need to respond, so this usually occurs in newborns and infants.
- Electrococciography (ECOG): measures electrical activity in the inner ear, produced by the cochlea and vestibulocochlear nerves in response to sound.
- Auditory Brain System Response (ABR) / Auditory Evoked Potential (AEP): This test examines the auditory nerves and the hearing centre in the brain and how well they work. This will determine if you have sensorineural hearing loss. Electrodes are placed on your head and connected to a computer. With the use of headphones, your brain wave activity records your responses to the sounds you hear.
Why is audiometry done?
An audiometry test is done to determine how well you can hear. This can be done as part of a routine exam or in response to a noticeable hearing loss.
Common causes of hearing loss are:
- Birth defects
- Chronic ear infections
- Hereditary conditions such as otosclerosis occur when abnormal bone growth prevents structures in the ear from working properly.
- Ear injury
- Inner ear disease, Meniere’s disease, or an autoimmune disease that affects the inner ear.
- Regular exposure to loud noises.
- Broken eardrum
Hearing loss is caused by hearing damage or prolonged exposure to loud noises. It sounds louder than 85 dB as you hear it at a rock concert, causing hearing loss after a few hours. If you are exposed to loud music or industrial noise daily, it is a good idea to wear headphones such as foam earplugs.
How audiometry is performed
There are some tests in audiometry. The pure tone test measures the quiet noise you can hear at different pitches. It uses an audiometer, a machine that reproduces sounds through headphones. Your audiologist or assistant will play different sounds such as tones and speaks in one ear at different intervals to determine your hearing range. The audiologist will give you instructions for each sound. They will most likely ask you to raise your hand when you can hear the noise.
Your hearing test allows your audiologist to assess your ability to distinguish speech from background noise. A sound pattern will play and you will be asked to repeat the words you heard. Word recognition can help identify hearing loss.
You can use the tuning fork to see how well you hear vibrations through your ears. Your audiologist will place this metal device against the bone behind your ear, mastoid, or use a bone oscillator to find out how many vibrations are passing through the bones to your inner ear. A bone oscillator is a mechanical device that transmits vibrations similar to a tuning fork.
This test does not cause any pain or discomfort and takes about an hour.
What happens during the test?
Audiometric tests are performed in a quiet, soundproof room. The headphones are placed on your head. You are asked to sit and speak. The headphones are connected to a machine that transmits tones and sounds to your ears, one ear at a time. The audiologist will ask you to raise your hand when he hears a noise.
For example, if you hear a noise with your left ear, raise your left hand, If you hear a noise with your right ear, raise your right hand. In some installations, you may be asked to press a button or to acknowledge that it has detected sound. The audiologist records each voice at the lowest volume you can hear. Before or after a simple audiometry test, tuning forks are also used to perform the Rinne and Weber tests. Each test assesses the different types of hearing loss.
To assess speech discrimination, you will be prompted to repeat the words you have heard. You will hear a series of two-letter words in a volume that gradually decreases on the test. In the second stage of the test, you listen to and repeat a series of one-letter words without changing the volume.
During the tympanometry and acoustic reflex exam, a soft plug is placed in your ear. The plug changes pressure makes a loud noise and tracks your responses to sound and various pressures. Small muscle reactions are measured by measuring the movement of the eardrum.
After the test, your audiologist will review your results with you. Depending on how well you hear the volume and tone, your doctor will advise you of preventive measures to take, such as wearing earplugs when there is a loud noise or wearing headphones.