The concept of deafness is used to name the lack or one limitation of the ability to hear . This disability can be absolute (what is known as cofosis ) or only partial (in this case, we talk about hearing loss ).
There are several reasons that can lead a person to develop deafness. In some cases it inherit and is present from birth, while in others it is a condition acquired from a impact or knock , a disease or even by being exposed, for a long time, to very strong auditory stimuli.
Every person Therefore, it may suffer different degrees of deafness, which are established according to an evaluation of audiometry . What makes this test possible is to determine if the subject has problems capturing the frequency or intensity of the sound. The results of the audiometry will allow the expert to know if the individual suffers from severe, moderate, mild deafness, etc.
It should be noted that the loss of the ability to hear can be caused by problems located in different parts of the auditory system. The damage, in this way, can be found in the outer ear , he middle ear , he inner ear or even in the brain .
There are several classifications of deafness based on various criteria. Among the most relevant is the one that is undertaken based on the moment in which said hearing loss is acquired. Specifically, according to that element we find the prelocutive deafness, which is what a person acquires before his third birthday, and the postlocutive deafness that is what an individual experiences when he has already developed what language is.
Following classification, we can establish that there is a second one that, in this case, is determined by taking as a starting point the degree of intensity of said deafness suffered by a person. Thus, it establishes the existence of the following types:
Mild. It supposes a loss of hearing between 20 and 40 dB which hinders the communication of the individual in noisy places but does not impede his development in the matter of language.
Half. Between 40 and 70 dB the patient loses in this kind of deafness that will make the acquisition and development of language much more difficult, so the use of a prosthesis and the help of a speech therapist will be necessary.
Severe. The loss is between 70 and 90 dB. In this case, the person has serious problems in spoken communication and will need the use of lip reading.
These three classes would also be associated with deep deafness, which makes the use of hearing aids or cochlear implants vital, and cofosis, which is the total loss of hearing.
Disability linked to deafness can be treated by headphones or others hearing aids . The hearing aid consists of a microphone that transforms the acoustic signal and converts it into an electrical signal, and a headset that completes the reverse path (passes from the electrical signal to the acoustic signal). What this system allows is to selectively amplify the electrical signal, allowing the person to listen to it.