Audiometry is a test that allows you to measure your hearing to determine the auditory capacity of the patient, indicating also possible causes of the hearing loss in cases where it is detected.
It can be done in two ways:
- Through the air::the ability to hear sounds or received noises is measured through the air, through the use of headphones.
- Through the bone:this method is used to measure the ability to hear sounds or noises through the bones of the head. To perform the
test is used a special speaker (vibrator) that emits vibrations behind of the ear.
The human ear is able to differentiate sounds whose frequencies oscillate between 20 and 20,000 Hz, although in a normal audiometry they are presented sounds or noises that range from 125 to 8,000 Hz. To the speak, the sounds we emit are in these levels, that's why they are the most important to measure.
How is an audiometry done?
You must enter a soundproof booth (isolated from noise) and put some headphones. Then, the otorrino (doctor who makes the tests), presents a series of sounds and noises. If you are able to hear the sounds you must press a button. Little by little these sounds will go down in volume until you no longer hear anything. The last recognized intensity will determine our hearing threshold for that frequency in particular.
That's when your hearing threshold is checked, it's say, what you are able to hear.
Representation of the results: the audiogram
The results of the audiometry are presented in summary form by means of two graphics, one for each ear, called audiograms. These diagrams show how much you are able to hear, by measuring the sounds in decibels and in Hz frequencies.
What information does an audiogram offer us?
A loss of up to 20 decibels is considered normal. When the hearing losses exceed this figure are considered "abnormal". The comparison Bone and airway tests are very useful to check if hearing loss is due to problems in the middle ear, or if the problem is in the inner ear, although they can also occur on both routes at the same time.
There are three types of losses:
- Driving or transmission hearing loss
- Perception or sensorial hearing loss
- Mixed hearing loss
The different levels of hearing reflected in the audiograms are:
- Normal hearing:when they are reflected above 25 decibels, value that shows that you have no problems to hear and understand.
- Average hearing loss: when values between 26 and 45 are obtained decibels If you get these figures in the audiogram, you have some
problems to listen and understand if they speak to you at a distance, in a low tone or when there is noise.
- Moderate hearing loss: when values between 46 and 65 are recorded decibels, which indicates that you have trouble understanding
conversations even if there is no background noise and you find it almost impossible listen to conversations in noisy places.
- Severe hearing loss:the audiogram reflects between 66 and 85 decibels This margin indicates difficulties to listen always and perceive sounds only when your interlocutor speaks to you very loudly and very close.
- Deep hearing loss:more than 85 decibels. If your audiogram record this value you do not hear even if you are shouted or there are no loud noises near you.