The hearing test, aka audiometry, measures how much sound you can hear. It is important that these tests are performed by a qualified audiometer. If you have hearing complaints, it is recommended to go to the ENT specialist, preferably at first. The ENT specialist will refer you to an audiometer if necessary.
How is the hearing test done?
The necessity of the patient to have a hearing test is decided by the ENT doctor. With these tests, hearing loss in the ear and the degree of this loss can be measured. During the test carried out in a soundproof room, a headset that connects the person as much as possible to the outside is worn. By giving sounds in different frequency ranges, the person’s reactions are evaluated together with bone and air conduction. When the person hears any sound, he is told to press the button on the remote control. The sound he hears can be low, very loud, thin or thick. Audiometry tests are of great importance for testing hearing loss in the ear.
What are the types of hearing test?
There are 4 different types of hearing test (audiometry test). These; pure sound audiometry, speech audiometry, tympanometry and acoustic reflex tests.
Pure sound audiometry
It is the most common hearing test. Pure sound audiometry determines the minimum volume that both ears can hear at different frequencies. Sounds are played in a soundproof cabinet through a special headset for the patient. With the help of the button, you can have an idea about whether the patient hears these sounds or how much they hear. The sound level heard is determined by this test. The hearing level of the airway and bone path is determined in this measurement. The main purpose of airway measurements is to find the level of hearing threshold. It measures the degree of hearing loss. The bone path gives information from the inner ear. In this measurement; sensorineural sensitivity of the individual is defined. Sensorineural sensitivity or sensorineural hearing loss can be defined as difficulty in understanding speech even if the volume of speech is high enough. Finally, extra attention should be paid to some situations when performing pure audio audiometry. These situations are as follows;
- If the patient has a complaint of tinnitus, he / she should report this to the audiometer and request that the voice be sent in a special tone to patients with a ringing complaint called warble.
- Patients should press the button not only at the highest volume they hear, but also at the lowest volume.
- If the bone conduction sound transducer is attached, it should be immobilized as much as possible.
Hearing and evaluating the human voice, the main task of the ear, forms the basis of speech audiometry. This test, which is generally applied in many centers as an answer to the question of how to make a hearing test, is based on human voice. As a stimulus, evaluation of the condition of this sound in the ear, giving information about the person’s ear functions is the main task of speech audiometry. The thresholds determined for this test are speech-taking threshold, speech-distinguishing threshold, comfortable listening threshold and disturbing level.
The threshold for receiving speech, also known as SRT (Speech Reception Threshold), is the severity of the patient based on the ability to hear the words he hears by 50%. The patient is given 6 words consisting of 3 syllables over 10dB – 15dB based on the pure sound average. Upon repeating the whole patient correctly, the sound intensity is reduced by 5dB and a different list with 3 syllables is given. If it repeats this list correctly, the sound volume is reduced by another 5dB. If the patient has 2 lines out of 6 words, the sound intensity given in the previous stage gives the result of the patient’s threshold to receive the speech.
Speech discrimination score, also known as SDS (Speech Discrimination Score), is based on adding the patient 25dB – 40dB and repeating the list of 25 single syllables on the verge of getting the speech. The correct answers are multiplied by 4%, and the figure obtained determines the level of patient distinguishing speech. This rate is around 90% for people who do not have any hearing problems.
- The comfortable listening threshold, also called MCL (Most Comfortable Level), is the remaining listening level between the threshold of receiving speech and the disturbing sound level.
- Disturbing level, also known as UCL (Uncomfortable Level), is the name given to the point where the patient is disturbed by the intensity of the sound level.
In hearing loss due to conduction type, patients have high SRT and UCL scores. According to the speech audiometry test, SRT value should be 20dB, MCL value 40-60 dB, SDS value 90-100%, UCL value 100-120 dB in people who do not have any hearing problems.
In the tympanometry test, which measures the pressure of the middle ear, air pressure is applied to the outer ear canal to measure mobility of the middle ear and eardrum. By measuring the mobility in the middle ear and eardrum, information about the function of these structures is obtained. Measurements are carried out with a probe placed in the ear. It is an easy test that can be easily applied even to babies. While tympanometry test is done, the eardrum should not have holes.
Acoustic reflex tests
The response of the stapes muscle in the middle ear to acoustic stimuli is called an acoustic reflex. It gives information about the ways of hearing up to the level of the brain stem. The information obtained with the acoustic reflex hearing test is interpreted together with other findings and gives an idea about the location of the condition causing the hearing loss.
How is the evaluation of the results of the hearing test?
The results of the hearing test are evaluated by the audiometrist and the ENT doctor. If you have a hearing loss or a condition that requires treatment, you should see your specialist doctor again.
What are the degrees of hearing loss?
The amount of an individual’s hearing loss is rated as mild, moderate, advanced, or severe. If we show the levels of this:
- You can hear low sounds up to 20 dBHL.
Mild hearing loss:
- Hearing loss in your ear, which has a better hearing ability, is between 25 and 39 dBHL. You will have some difficulty following what is spoken in noisy environments.
Moderate hearing loss:
- Hearing loss in your ear, which has a better hearing ability, is between 40 – 69 dBHL. You will have difficulty following up on what is spoken without a hearing aid.
Advanced hearing loss:
- Hearing loss in your ear, which has a better hearing ability, is between 70 and 89 dBHL. Powerful hearing aids or implants are required.
Severe hearing loss:
- Hearing loss in your ear, which has a better hearing ability, starts at 90 dBHL. You need more lip reading and / or sign language or implant use.