Audiometry

Hearing tests, also called audiometry, measure how well a person can hear sounds. It is important that these tests be performed by a professional audiometrist. If you have a hearing problem, it is recommended that you first see an otolaryngologist. The ENT may be able to refer you to an audiometrist.

What to Expect During the Hearing Test

Your ENT doctor will recommend whether you need a hearing test. This test measures the presence and extent of hearing loss in the ear. During the test, which takes place in a soundproofed room, the patient wears a headset that blocks contact with the outside world as much as possible. Sounds in different frequency ranges are then played to assess bone and air conduction, as well as the person's response. When they hear a sound, they are asked to press a button on a remote control in their hand. The sounds the patient hears may be soft, very loud, low pitch, or high pitch. Audiometric testing is very important in assessing hearing loss in the ear.

What are the types of hearing tests?

There are 4 different types of hearing tests (audiometry test) such as pure tone test, speech test, tympanometry and acoustic reflex testing.

Pure tone test

It is the most commonly performed hearing test. Pure tone tests measure the minimum volume that both ears can detect at different frequencies. In a soundproof booth, the patient listens to sounds wearing special headsets. At the push of a button, the patient is asked to identify whether or not the sound can be heard and if so, how strong the sound is. This test determines how much of the sound is audible. Taking this test helps measure the level of hearing in the airway and bony ducts. The main purpose of airway measurement is to define the level of the hearing threshold. This determines how severe the hearing loss is. Performing bone conduction measurements provide us with information to be obtained via the inner ear. This measurement determines a person's sensorineural sensitivity. Sensory sensitivity or sensorineural hearing loss can best be defined as difficulty understanding speech, even when the speaker volume is sufficiently loud. In closing, extra special care should be taken when performing pure tone audiometry under the following circumstances. These conditions are as follows;

• In case the patient suffers from tinnitus (ringing in the ears), he/she should see an audiometrist and ask for warble tones which is a special tone for patients with tinnitus.
• Patients must not only press the button when the volume is the highest but also at the lowest volume they can hear.
• In case of the patient wears bone conduction headphones, it is very important to remain very still as much as possible.

Speech Test

Hearing and analyzing the human voice, the essential task of the ear, is the basis of a speech test. This test, which is usually practiced in many clinics as an answer to the question of how to conduct a hearing test, is based on a human voice. The main mission of a speech test is to evaluate the recognition of this sound as a stimulus in the ear and to provide information about the functioning of a person's ear. The thresholds for this test are: speech recognition threshold, speech detection threshold, most comfortable level and uncomfortable level.

Speech Reception Threshold, also known as SRT, is a loudness level based on the patient's ability to hear 50% of the words. Given six words consisting of three syllables, the patient is given a loudness of 10 dB to 15 dB or higher, depending on the average of the pure tones. If the patient repeats all the words correctly, the loudness is reduced by 5 dB and another list of three syllables was given. If the patient repeats this list correctly, the volume is reduced by another 5 dB. If the patient correctly repeats the six words twice, the volume given in the previous step is the result of the patient's language acquisition threshold.

Speech discrimination score, also known as SDS, is based on the results a patient obtains at the speech recognition threshold after repeating a list of 25 monosyllabic words, adding 25 dB to 40 dB. Correct answers are multiplied by 4% and the result determines the patient's level of speech discrimination score. This figure is around 90% for people who have no hearing problems.

• Most Comfortable Level, also known as MCL, is the listening level between the speech reception threshold and the uncomfortable sound level.
• Uncomfortable level, also known as UCL, is the point at which the patient is uncomfortable with the loudness of the sound level.

Patients with conductive hearing loss have high SRT and UCL values. Based on a speech test, the SRT value should be 20 dB, the MCL value should be 40-60 dB, the SDS value should be 90-100%, and the UCL value should be 100-120 dB for a person without hearing problems.

Tympanometry

A tympanometry test, which measures middle ear pressure, evaluates the mobility of the middle ear and eardrum by applying air pressure to the ear canal. It is possible to obtain information about the function of these structures by measuring the mobility of the middle ear and tympanic membrane. The measurement is performed by inserting a probe into the ear. It is an easy test that can be easily applied to even babies. The eardrum must not be punctured in order to perform the tympanometry test.

Acoustic reflex testing

Acoustic reflex is the response of the stapedius muscle to a high-intensity sound stimulus. This test provides information about the auditory pathways all the way to the brainstem. Combined with other results, the results from acoustic reflex testing may help determine the location of a problem that is causing hearing loss.

How to Interpret Hearing Test Results

Hearing test results are interpreted by an audiologist and an ENT doctor. If any hearing loss or treatment-critical conditions are detected, a second consultation with a specialist is required.

Degrees of Hearing Loss

A person's hearing loss is categorized as normal, slight, moderate, severe, or profound. These categories are as follows:

Normal hearing ability:

• You can hear sounds down to 20 dB HL.

Slight Hearing Loss:

• The hearing loss in your ear that hears better is between 25 and 39 dB HL. You have trouble following conversations in noisy environments.

Moderate Hearing Loss:

• The hearing loss in your ear that hears better is between 240 and 69 dB HL. Without hearing aids, you might find it difficult to follow the words being spoken.

Severe Hearing Loss:

• The hearing loss in your ear that hears better is between 70 and 89 dB HL. You need powerful hearing aids or implants.

Profound Hearing Loss:

• The hearing loss in your one ear that hears better begins at 90 dB HL. Lip reading and/or sign language or the use of implants may be required.