The 8 types of hearing impairment (and their characteristics)

Hearing problems are more common and diverse than they appear. Many people in our environment have problems hearing well and need medical devices and interventions to achieve hearing within the normal range.

Not all hearing problems are the same. There are those who cannot hear anything at all, while others have a lower hearing range than most people but still hear.

There are several types of hearing impairment and there are many criteria to classify them, criteria that we are going to see below in addition to mentioning some of the main causes behind hearing problems.

• Related article: "Cochlea: what is it, parts, functions and associated pathologies"

Types of hearing impairment, classified

Hearing disability is understood to be any condition in which the affected person has reduced ability to perceive sound, which in turn is accompanied by problems in communication verbal. There are several types of hearing impairment, depending on the severity of the hearing loss and what problem has made the person unable to hear well.

The severity of a hearing impairment is considered based on the minimum sound that the affected person can hear with their better ear.. The more decibels (dB), the louder the sound and, if there is a loss close to 90 dB, it is generally referred to as deafness. If there are hearing problems but the hearing is below the 90 dB limit, diagnoses range from mild hearing loss to hearing loss and deafness.

In itself, hearing impairment is not a disease, but the consequence of different medical conditions that can cause hearing damage. Whether it is a temporary or permanent loss, many people with disabilities hearing can lead to a completely normal life using various resources to improve their hearing. Among these improvements we can highlight hearing aids and cochlear implants that would be the equivalent of glasses for those with vision problems.

Not being able to hear not only affects hearing itself, but also makes communication and language difficult. If the person was born with hearing problems it will be difficult for him to learn his mother tongue, having difficulties in grammar, spelling and vocabulary, with its implications on a social level by not daring to start a conversation or be in an environment with several people talking.

There are several criteria for classifying the types of hearing impairment. As it is a very heterogeneous type of disability, no single classification can be established, although it must be said that those that exist are not mutually exclusive. Basically, we can classify them based on the moment of appearance, severity, prognosis and where the injury is located.

According to its moment of appearance

Depending on when the person began to manifest hearing impairment, we can talk about:

1. Congenital

The person is born with something that causes hearing problemsThis could be due to a malformation of the structures found in the ear or due to a malfunction at the nervous or cellular level.

The fact that it is congenital does not mean that it is detected early, although the ideal is that it should be so in order to intervene as soon as possible. In this regard, they are divided between hearing disabilities that appear between the time of birth and 3 years and those that appear after that age.

2. Acquired

Hearing impairment occurs throughout life and can be caused by multiple factors, such as the use of ototoxic drugs (which damage hatred) or injuries to the eardrum.

Not all acquired deafness is caused by external and avoidable factors, since in many cases Sometimes hearing impairment appears with age or as a result of a disease degenerative.

Within acquired deafness there are three types depending on the moment in which the problem was acquired: prenatal, caused during pregnancy; neonatal; produced during or immediately after delivery; and postnatal, produced long after being born.

Whether they are congenital or acquired, it is very important to see if they appeared before or after the person acquired the language. In the event that he acquired deafness before learning to speak, it would be a prelingual hearing disability, while if it appears afterwards it is a postlingual hearing impairment.

According to its severity

Depending on how much or little the person can hear and how necessary it is to resort to help special to achieve adequate hearing we talk about three main types of disability auditory.

3. Cofosis

The cofosis is the hearing condition in which the person cannot hear at all. Some consider it a synonym for profound deafness, although in this case the person can hear sounds at a very high volume (90 dB).

4. Deafness

Deafness itself is hearing impairment in which the person does not hear sounds below 75 dB, being especially serious if they cannot hear them below 90 dB.

The person is deaf, but it is not a profound deafness and as serious as the cofosis because in this case the affected person can hear the sounds if they are amplified by means of special devices.

5. Hearing loss

Hearing loss is less severe than deafness, since the person can hear below 75 dB but not the full range of normal hearing.

In order to diagnose any of the three hearing conditions that we have just talked about, it is necessary to perform an audiometry which can give the following results:

• Normal hearing: very low sounds can be heard, equal to or below 20 dB
• Mild hearing loss: the lowest audible sound is between 20 and 40 dB.
• Medium hearing loss: sounds are detected from 40-70 dB (hearing loss).
• Severe hearing loss: only heard from 70-90 dB (deafness).
• Profound hearing loss: you hear above 90 dB (profound deafness) or do not hear anything (cofosis).

Hearing impairment does not have to affect both ears at the same time. Hearing impairment can be unilateral or bilateral, that is, it may be that one ear is damaged and the other is healthy, or that both have problems capturing and sending sounds to the brain. In case of having a healthy ear this can be used to compensate the situation and make the person have a relatively normal life without requiring too many hearing aids, although it will be difficult for you to detect where the sound.

Depending on the location of the injury

Some cases of deafness are caused by an injury which hinders the perception of sounds and their interpretation at the cortical level. Depending on where this injury is located, we can talk about the following types of deafness.

6. Driving deafness

The problem is in either the outer ear or the middle ear. These are the ones with the best prognosis, since treating them is relatively easy. Surgical intervention may be required, such as inserting an artificial eardrum, or even require a mere cleaning of the ear canal, removing a wax plug that is affecting the hearing of the patient.

7. Sensorineural deafness

Sensorineural deafness is difficult to treat since the lesion is in deeper and more delicate places. The damage can be in the inner ear, the auditory nerve, or even the auditory cortex, that is, the place in the brain where acoustic stimuli are interpreted.

• You may be interested in: "The 10 parts of the ear and the process of receiving sound"

8. Mixed

Hearing impairment is due to a problem in the outer and / or middle ear along with a problem more internally, in the inner ear or the acoustic nerve.

Forecast

As we have commented, hearing impairment is not in itself a disease, but the consequence of a health problem that has among its symptoms an alteration in the ears or nerve damage auditory. Depending on what causes it and if it is possible to solve it, this hearing impairment can be permanent or temporary.

If it is permanent, hearing cannot be recovered without the use of special aids and can even go further. Over the years, a problem of initial hearing loss becomes a cofosis after a while. On the other hand, if the hearing impairment is transitory, it can be cured by eliminating what causes it or curing the disease or injury that had induced it, although there may be sequelae in the form of a very mild hearing loss

Common causes

There can be many causes behind hearing impairment, some being more common than others. These causes vary greatly depending on the age of the affected person, in addition to the fact that they can make the diagnosis something more or less serious. A deafness that appears in childhood is not the same as one in adulthood or old age, and the degree to which it can be treated and corrected is also different..

Causes in children

Deafness in children can have congenital causes. Many hearing disabilities in childhood are associated with specific syndromes, currently known to more than 400 medical conditions involving hearing loss or non-disabling hearing impairment. Some examples are Waardenburg syndrome, with partial albinism and deafness; Usher syndrome, with hearing loss and visual problems; and Alport syndrome, with deafness and kidney dysfunction.

Congenital deafness is due to the inheritance of a gene that has the syndrome or disease that causes hearing impairment. In most of these cases, the problem is usually at the level of the cochlea, that is, in the inner ear, although there are congenital deafness where the damage is more external, such as a damaged ear canal or malformations in the ear.

Some children are born with hearing impairment but not caused by genetic problems, but by perinatal disorders. Prematurity, low birth weight, infections that the mother may have had during pregnancy, and poisoning with ototoxic substances can cause deafness in the newborn. Hearing impairment will manifest itself from the moment of birth and will be evident when the child reaches 3 years of age, at which time he should know how to speak but since he cannot hear well he has not yet learned.

There may also be events that worsen the hearing health of the newborn in the first years of life. Your hearing is very vulnerable to external elements that can damage it, such as viral diseases of the type meningitis, measles or mumps, diseases that can leave problems as sequels auditory. They are also sensitive to ototoxic drugs, trauma, the introduction of foreign bodies into the ear canal (eg. g., swabs) and the appearance of plugs.

Causes in adults

In the case of young adults, it is common to find cases of hearing loss due to acoustic trauma caused by being exposed to sounds above 100 dB, such as speakers in clubs or drills without using adequate acoustic protection (p. e.g. plugs). Victims of bombings or who have witnessed the detonation of firearms may also have their hearing impaired.

Other factors that lead to hearing problems in adulthood are the use of ototoxic medications, the appearance of earplugs wax in the ear canal and the appearance of tumors in the auditory nerve, such as neurinoma of the nerve acoustic. Depending on what causes it, how long the problem has been and how early a specialist has been consulted, the deafness will be reversible or not.

Causes in old age

Deafness is usually associated with old age. As you get older, a medical condition called otosclerosis may develop, which consists in that the joints of the ossicles that form the inner ear become more rigid, which makes them vibrate less when a sound affects them. Less stiffness means worse driving and, therefore, the person hears less. In turn, the receptors in the middle ear degenerate, being less effective and causing poor hearing.

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