Hearing Test, This is What You Need to Know

Hearing test is an examination procedure to determine someone's listening ability. The examination is done by measuring how well the sound is delivered to the brain. The sound that is heard comes from vibrations in the air around us, which then forms sound waves that propagate in a certain frequency. The process of hearing occurs when sound waves enter through the ear and are delivered by nerves to the brain. This hearing process will be interrupted if there is a damaged part of the ear, resulting in hearing loss. Hearing loss can be divided into conductive deafness and sensorineural deafness. Conductive deafness occurs when there is a problem in the ear canal or middle ear, so that the sound waves are blocked and cannot enter the inner ear. Conductive deafness can cause temporary or permanent hearing loss. While sensorineural deafness occurs if the cochlea (an organ in the inner ear) or the auditory nerve does not function normally, so the sound is not transmitted to the brain. Sensorineural deafness is generally permanent, and can occur in one or both ears. Conductive and sensorineural deafness can occur separately or together.

Hearing Test Indications

The doctor will recommend hearing tests on someone who has the following signs:

• Feeling a buzz in the ear (tinnitus).
• Speak too loudly to make the other person interrupted.
• Often asking the other person to repeat the speech
• Difficult to hear the conversation, especially in a crowded atmosphere.
• Watching television with a loud voice, so disturbing others.
• Having congenital abnormalities or congenital birth defects in the ear, such as microtia.

Hearing Test Preparation

Some things that patients need to know before undergoing a hearing test include:

• Let your doctor know if you have recently heard a loud noise that makes the ear ache and ring, or have an ear infection.
• Tell your doctor if you experience interference in listening to conversation, or feel the symptoms of hearing loss.
• Tell your doctor if you are taking antibiotics that can damage the function of the hearing organ, such as gentamicin.
• The doctor will examine the inside of the ear. If there is hardened earwax, the doctor will remove it so that it does not affect the test results.
• Some tests are done by wearing headphones. Patients will be asked to take off their glasses, earrings, hair accessories, and hearing aids so as not to interfere with the test.
• For those who will undergo the BERA test, patients will be asked to wash before the test.

Hearing Test Procedure

There are several types of hearing tests that hearing loss patients can undergo. Consult the ENT doctor about which test is right to do.

Whisper test

In a whisper test, the doctor will ask the patient to close the ear hole that is not examined with a finger. After that, the doctor will whisper a few words, or whisper a combination of letters and numbers. When whispering to the patient, the doctor will be less than 1 meter behind the patient, to prevent the patient from reading lip movements. Patients will be asked to repeat what the doctor said. If the patient cannot repeat the whispered word, the doctor will use a different combination of letters and numbers, or repeat the pronunciation of the word louder, so the patient can hear it. Then the test is repeated on the other ear. Patients are considered to have passed the whisper test if they are able to repeat 50% of the words the doctor uttered.

Tuning fork test

In this test, a tuning fork with a frequency of 512Hz is used to determine the patient's response to sound and vibration near the ear. The tuning fork test can be done with the Weber test and the Rinne test. For the Weber test, the doctor will bang the tuning fork on a hard object to create vibrations, then the tip of the tuning fork is placed in front of the forehead, nose, or teeth. In patients with normal hearing, sounds will be heard loud in both ears. If the sound is louder in the ear in good condition, the patient is experiencing sensorineural deafness. Whereas if the sound of a tuning fork is heard more clearly in poor ear conditions, it means the patient has conductive deafness. The tuning fork test can also be done with the Rinne test. Just like the Weber test, the doctor will bang the tuning fork to create vibrations. Then the tuning fork is placed at the back of the ear and side of the patient's ear, to compare bone conductivity and air conductivity. In patients whose hearing is normal, the patient will hear a sound next to the ear (air conduction) twice as long as if they hear a sound behind the ear (bone conduction). In sensorineural deafness, air conductivity will also sound longer than bone conductivity, but not up to 2 times. Whereas if the patient has a hearing loss conduction, the bone conduction will sound longer than the air conduction.

Speech audiometry test

This test is used to find out how well the patient hears and understands simple conversation. In this test, patients will be asked to repeat the words the doctor said, ranging from soft voice to loud. In the first stage of the test, the doctor will say words consisting of two syllables in a soft voice, then the patient is asked to repeat with an accuracy of at least 50%. Then in the second phase of the test, the doctor will say 50 words that sound similar to a loud voice (40 decibels), and the patient is again asked to repeat the words spoken. Speech audiometry results can be used to determine whether hearing aids are needed by patients, and to determine the location of hearing organ damage. The patient's hearing is considered normal if they can repeat 90 to 95% of the words the doctor says during the test.

Pure tone audiometry test

This test uses an audiometer, a device that produces pure tones, and is played on the patient through headphones. These tones vary in the frequency and intensity of the sound, starting from 250Hz, up to 8000Hz. The test will start with the intensity of the sound that is still audible, then gradually reduce it until it is no longer heard by the patient. Then, the sound intensity will be increased again until the patient can hear it. Patients will be asked to give a signal by pressing the button provided, if they can still hear a sound even though it is very faint. Audiometry tests are carried out in a special room. In this test, each ear will be tested separately, starting first in the ear in good condition. The patient will undergo several tests, where in each test, the tone played on the patient will be higher. After that, the headphones will be removed, and the vibrator will be attached to the back of the ear. The patient will again be asked to respond if he hears a tone.

Auditory Brain Stem Response Test

This test is also called the brainstem evoke response audiometry (BERA) test. In this test, the doctor uses electrodes that are connected to the machine to record the patient's brain response. In pediatric patients who cannot calm down when electrodes are placed, the doctor will give a sedative. The following procedures are performed on the BERA test:

- Electrodes are attached to the crown and each earlobe of the patient.
- After electrodes are attached, patients will be asked to use earphones.
- 'click' sound and other sounds will be played to the patient through earphones.
- The machine will record the patient's brain response to sound.

Test results will show an increase in brain activity every time the patient hears a sound produced by the machine. If the test results do not show an increase in brain activity when the sound is heard, chances are the patient is deaf. Abnormal test results can also mean that there is interference with the patient's brain or nervous system.

Otoacoustic emissions (OAE)

The autoacoustic emissions (OAE) test is used to check for disorders of the inner ear, specifically the cochlea (snail house). Generally done to check hearing loss in newborns, but can also be done for adults. In this test, a small instrument with earphones and microphone is placed in the ear canal. Then, the doctor will deliver sound to the patient's ear through earphones, and the microphone will detect cochlear responses in the form of vibrations. In normal hearing, the vibration will produce a small sound that echoes into the ear canal. The sound from the vibration is measured. The response produced by the cochlea will be displayed on the monitor screen, so the patient does not need to give any sign if he hears a sound. The doctor will assess what sounds produce the response, and how the strength of the response. Through this test, the doctor can determine the type of hearing loss experienced by the patient. OAE can also detect blockages in the outer and middle ear. If there is a blockage, the sound will not enter the inner ear, and the cochlea will not produce any response.

Tematometri

Before running the test, the doctor will first examine the patient's ear canal to make sure there is no ear wax or other objects that are blocking the eardrum. After making sure the ear canal is clean, the doctor will install a special instrument in each patient's ear. A slight discomfort will be felt by the patient when the device is paired. Once installed, the special instrument will blow air in varying pressure into the ear, to make the eardrum move. The eardrum movement will then be displayed in a graph on the tympanogram. The graph on the tympanogram will show whether the patient's eardrum is moving normally, is too stiff, or is moving too much. Through the tympanogram, the doctor can also find out if there is a tear in the patient's eardrum or fluid in the middle ear. Patients are not allowed to talk, move or swallow during the test, as this will affect the results of the test. Tympanometry results can be divided into normal and abnormal results. Patient hearing is considered to be no problem if the air pressure in the middle ear ranges from +50 to -150 decapascal, there is no fluid in the middle ear, and the movement of the eardrum is still normal. While abnormal results can indicate the presence of:

- fluid or tumor in the middle of the ear.
- Dirt that covers the eardrum.
- Hole or wound in the tympanic membrane.

Tympanometry is only done to examine the middle part of the ear. The doctor will advise the patient to undergo another test, if the tympanometry test shows abnormal results. After the Hearing Test The doctor and patient will discuss the test results, including the level of hearing loss experienced by the patient, and the possible use of hearing aids. Patients are also advised to wear ear protectors if they are in a noisy place. Hearing loss is measured in decibels (dB). Patients who undergo a hearing test can get the following results:

• Mild hearing loss (21-45 dB). Patients have difficulty distinguishing spoken words in a low voice.
• Moderate hearing loss (46-60 dB). It is difficult for the patient to hear what is being discussed, especially if there is loud noise around him, such as the sound from television and radio.
• Moderate to severe hearing loss (61-90). Patients have difficulty hearing ordinary conversation.
• Severe hearing loss (91 dB). The patient has difficulty hearing almost all sounds. Generally patients with severe hearing loss need hearing aids.

Side Effects of Hearing Tests

Hearing tests are safe for everyone to do, and don't cause any side effects.