What is audiometry?
An audiometry is a test that evaluates hearing function in terms of pitch, balance and loudness of sound. It focuses on the functioning of the inner ear. The human ear is capable of perceiving sounds ranging from 20 to 20,000 Hertz (Hz). In addition, it can hear sounds ranging in intensity from 20 decibels upwards.
What does it consist of?
Audiometry involves several tests. Tone audiometry measures the softest and quietest sounds a person can hear at different pitches. For this, the ENT specialist uses the audiometer, which is a special machine that reproduces sounds through headphones that the patient will put on while seated in a soundproof booth with a window.
Speech audiometry evaluates how well the patient can hear speech at different pitches. Thus, the test is divided into tonal and speech audiometry. In tonal audiometry, the airway and the bone pathway are evaluated, which in both cases involves the examination of the ears separately, with the patient located inside the soundproof and hermetically sealed booth. During the examination the patient should put on headphones and the specialist, located outside the booth, will play a series of sounds, from higher to lower volume, until they are inaudible. The patient should alert the specialist when he/she is able to hear each sound by raising his/her hand. The last sound perceived determines the auditory threshold, i.e., at what intensity the patient can hear at a certain frequency. During the inspection of the bone pathway, a vibrator is placed behind the patient’s ear, in the mastoid, where it receives the sound.
Speech audiometry is also performed with the patient in a booth and headphones, but instead of sound, words are spoken at different volumes, which must be repeated exactly. A word recognition test is also performed which measures the patient’s ability to discern between speech and background noise.
In addition, tympanometry tests can uncover any problems with wax or fluid buildup, damage to the eardrum, bone or even middle ear tumors.
Acoustic reflex testing will be able to pinpoint where any hearing impairment may be located.
Why is it performed?
Audiometry can detect hearing loss and is performed when a patient has hearing problems or as part of a routine examination. An audiometry usually determines whether the person suffers from sensorineural hearing loss (when there is damage to the nerves or cochlea) or conductive hearing loss (when the damage is in the eardrum or ossicles). Hearing loss usually results from:
- Birth defects
- Chronic ear infections
- Regular exposure to loud noises
- Damage to the eardrum or inner ear
- Diseases of the inner ear
- Genetic diseases
Preparation for audiometry
No special preparation is necessary for audiometry.
What does the test feel like?
During the test the patient will not feel any discomfort. The duration of the test varies depending on whether it is an initial evaluation, which may take 5 to 10 minutes, or a more detailed evaluation, which may take up to an hour.
Meaning of abnormal results
The results are displayed on a graph called an audiogram. The specialist will review the results and, if it is confirmed that the patient suffers from hearing loss or hearing impairment, it will be analyzed in depth to determine the available treatments. These could include the possibility of using a hearing aid or, in more severe cases, a cochlear implant or middle ear implant.