The 8 types of hearing loss (and their characteristics)

Hearing problems are more common and diverse than they seem. Many people around us find it difficult to feel well and need medical equipment and procedures to get their hearing within the normal range.

Not all hearing problems are the same. Some may not hear anything at all, while others have a lower hearing range than most people, but still feel.

There are several types of hearing loss and many criteria to classify them, Criteria that we will see below in addition to mentioning some of the main causes of hearing problems.

    Types of hearing loss, classified

    By hearing impairment we mean any condition in which the affected person has reduced their ability to perceive sound, which is also accompanied by problems in verbal communication. There are several types of hearing loss, depending on the severity of the hearing loss and the problem that caused the person to feel unwell.

    The severity of a hearing loss is considered based on the minimum sound that the affected person can hear with their best sense.. The higher the decibels (dB), the louder the sound and in the event of a loss close to 90 dB, it is generally referred to as deafness. If there are hearing problems but you feel below the 90dB limit, diagnoses range from mild hearing loss to hearing loss and deafness.

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

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

    There are several criteria for classifying types of hearing loss. As this is a very heterogeneous type of disability, a single classification cannot be established, although it must be said that those that do exist are not mutually exclusive. Basically, we can categorize them based on the time of onset, severity, prognosis, and location of the lesion.

    According to its time of appearance

    Depending on when the person started to manifest hearing loss, we can talk about:

    1. Congenital

    The person was born with something that causes them hearing problems, May be due to a malformation of the structures found in the ear or to a dysfunction at the nervous or cellular level.

    Being congenital doesn’t mean it’s detected early, although it ideally should be so that you can intervene as quickly as possible. In this aspect, they are divided between hearing impairments that appear between the time of birth and 3 years and those that appear after reaching this age.

    2. Acquired

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

    Not all acquired hearing loss is caused by external and preventable factors, as in many cases hearing loss develops with age or as a result of degenerative disease.

    In acquired deafness, there are three types depending on when the problem was acquired: prenatal, caused during pregnancy; newborns; produced during or immediately after delivery; and postnatal, produced long after birth.

    Whether congenital or acquired, it is very important to see if they appeared before or after the person acquired the language. If you acquire deafness before learning to speak it would be prelocutionary hearing loss, whereas if it appears later it would be postlocutionary hearing loss.

    Depending on its severity

    Depending on how little or how much the person may feel and the need for special aids to achieve adequate hearing, we are talking about three main types of hearing loss.

    3. Cofosi

    The cofose is a state of hearing in which the person can hear absolutely nothing. Some consider it to be synonymous with profound deafness, although in this case the person can hear sounds at a very high volume (90 dB).

    4. Deafness

    Deafness itself is the hearing loss in which the person cannot hear sounds below 75 dB, and is particularly serious if they cannot hear them below 90 dB.

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

    5. Hearing loss

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

    To be able to diagnose one of the three hearing ailments mentioned above, it is necessary to perform audiometry which can give the following results:

    • Normal hearing: you may hear very low sounds equal to or less than 20dB
    • Mild hearing loss: The lowest perceptible sound is between 20 and 40 dB.
    • Average hearing loss: sounds are detected between 40 and 70 dB (hearing loss).
    • Severe hearing loss: audible only 70 to 90 dB (deafness).
    • Profound hearing loss: listening above 90 dB (profound deafness) or hearing nothing (cofose).

    Hearing loss does not have to affect both ears at the same time. Hearing loss can be unilateral or bilateral, which means that one ear may be damaged and the other may be healthy, or both may have difficulty picking up and sending sounds to the brain. If you have a healthy ear, it can be used to compensate for the situation and allow the person to lead a relatively normal life without the need for too many hearing aids, although it will be difficult to detect where the sound is coming from. .

    Depending on the location of the injury

    Some cases of deafness are caused by an injury that interferes with 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. Deafness at the wheel

    The problem is either in the outer ear or in the middle ear. These are the ones with the best prognosis, because treating them is relatively easy.. Surgery may be necessary, such as the insertion of an artificial eardrum, or even requiring a simple cleaning of the ear canal, the removal of a plug of earwax that affects the patient’s hearing.

    7. Sensorineural deafness

    Sensorineural hearing loss is difficult to treat because the lesion is located in deeper and more delicate places. The damage can involve the inner ear, the auditory nerve, or even the auditory cortex.That is, the place in the brain where acoustic stimuli are interpreted.

      8. Mixed

      Hearing loss is due to a problem in the outer ear and / or the environment as well as to a problem on a more internal level, in the inner ear or the acoustic nerve.


      As we have mentioned, hearing loss is not in itself a disease, but the consequence of a health problem that has among its symptoms an alteration of the ears or damage to the auditory nerve. According to this that it causes and if it is possible to repair it, this hearing loss can be permanent or transient.

      If it is permanent, hearing cannot be recovered without the use of special aids and may even go further. over the years, turning an initial problem of hearing loss into a cofose after some time. On the other hand, if the hearing loss is transient, it can be cured by eliminating what caused it or by curing the disease or injury that caused it, although there may be sequelae in the form of very mild deafness.

      common causes

      There can be many causes behind hearing loss, some of which are more common than others. These causes vary greatly depending on the age of the affected person, and can make the diagnosis more or less serious. Deafness that started in childhood is not the same as that in adulthood or old age, and the extent to which it can be treated and corrected is also different..

      Causes in children

      Deafness in children can have congenital causes. Many childhood hearing disorders are associated with specific syndromes, currently known as over 400 medical conditions in which there is 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 loss. In most of these cases, the problem is most often in the cochlea, that is, in the inner ear, although there is also congenital deafness where the lesions are more external, such as a duct, damaged hearing, or abnormalities in the ear.

      Some children are born with hearing loss but not caused by genetic problems, but perinatal disorders. Prematurity, low birth weight, infections the mother may have had during pregnancy and poisoning with ototoxic substances can cause deafness in the newborn. Hearing loss will start from birth and will be evident by the time the child turns 3, when he should be able to speak but since he is not feeling well he has not yet learned.

      There may also be events that worsen a newborn’s hearing health during the first years of life. His ear is very vulnerable to external elements that can damage it, such as viral diseases such as meningitis, measles or mumps, diseases that can cause hearing problems. They are also susceptible to ototoxic drugs, trauma, the introduction of foreign bodies into the ear canal (for example, 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 due to exposure to sounds greater than 100 dB, such as nightclub speakers or drills without using adequate hearing protection (For example, taps). Victims of bombings or who witnessed the explosion of guns may also have hearing loss.

      Other factors that lead to hearing problems in adulthood are the use of ototoxic drugs, the appearance of wax plugs in the ear canal, and the appearance of tumors in the auditory nerve, like this is the case with neuroma of the ear. Depending on the cause, the duration of the problem and the time spent with a specialist, the deafness will be reversible or not.

      Causes in old age

      Deafness is generally associated with old age. As you get older, you can develop a condition called otosclerosis, That is, the joints of the bones that make up the inner ear become more rigid, causing them to vibrate less when a sound hits them. Less stiffness implies poorer driving and therefore the person listens less. In turn, the receptors in the middle ear degenerate, are less effective, and make you feel bad.

      Bibliographical references:

      • Marchesi, Álvaro (1987). The cognitive and linguistic development of deaf children.
      • Alliance: Madrid,
      • Morton, NE (1991). Genetic epidemiology of hearing loss. Annals of the New York Academy of Sciences, 630 (1), 16-31.
      • Olusanya, BO and Newton, VE (2007). Priorities for the global burden of hearing loss in children and disease control for developing countries. The Lancet, 369 (9569), 1314-1317.
      • Dodge, PR, Davis, H., Feigin, RD, Holmes, SJ, Kaplan, SL, Jubelirer, DP, … and Hirsh, SK (1984). Prospective evaluation of hearing loss as a sequel to acute bacterial meningitis. New England Journal of Medicine, 311 (14), 869-874.
      • World Health Organization. (2001). International Classification of Functioning, Disability and Health: ICF. World Health Organization.
      • Discapnet. (Sf). Hearing impairment. Spain Retrieved from:

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