Audiometry is a hearing test that evaluates how well a person can hear and understand sounds and words. It is especially useful for detecting significant hearing changes in people who work in very noisy environments.
There are two main types of audiometry: tonal and speech. Tonal audiometry identifies the range of frequencies a person can hear, while speech audiometry focuses on how well a person can understand specific words.
This test is done in a special soundproof booth, takes about 30 minutes, and does not cause pain. It is usually performed by an audiologist.
Main types
There are two main types of audiometry, which are:
1. Tonal audiometry
Tonal audiometry is a test used to assess a person’s hearing, allowing measurement of the quietest and loudest sounds they can hear across frequencies from 125 to 8000 Hz.
The hearing threshold is defined as the lowest sound intensity at which a pure tone at a given frequency is heard 50% of the time.
2. Speech audiometry
Speech audiometry evaluates a person’s ability to understand certain words and distinguish specific sounds, which are played through headphones at different sound intensities. The person must then repeat the words spoken by the examiner.
How to prepare for the test
No special preparation is needed for this test. However, in some cases, a person may be advised to avoid exposure to loud and constant noise during the 14 hours before the test.
How the test is performed
The audiometry test is performed in a soundproof booth to prevent outside noise from interfering with the exam.
According to the American Speech-Language-Hearing Association (ASHA), pure-tone testing is commonly performed with earphones or headphones, and the person is asked to signal when a sound is heard, such as by raising a hand or finger.
These sounds are played at different frequencies and are alternated between the ears. This test does not cause pain and lasts about 30 minutes.
Test results
There are different types and degrees of hearing loss, and being unable to hear pure tones below 25 dB indicates some level of hearing loss.
In detailed audiometry, hearing is considered normal when sounds from 250 to 8000 Hz can be heard at 25 dB or less.
The degree and type of hearing loss can help suggest the underlying cause and the likelihood of recovery. Conditions that may be associated with hearing loss include labyrinthitis, Ménière’s disease, a perforated eardrum, and acoustic trauma caused by very loud sounds.
How to prevent hearing loss
To prevent hearing loss, it is important to follow certain recommendations, such as:
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Keep the volume low on audio devices
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Use well-fitted headphones and, if possible, choose noise-canceling models
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Wear earplugs in very noisy places
Exposure to loud sounds can cause temporary hearing loss or ringing in the ears. According to the WHO, prolonged or repeated exposure to loud sounds can permanently damage hearing, leading to irreversible hearing loss and tinnitus.