Hearing loss refers to a partial loss of hearing. Permanent or temporary, this deafness can be more or less important depending on the case.

Hearing loss is a type of deafness, that is, a disorder affecting the perception of sounds. It is characterized by a partial hearing loss, unlike anacusis, or cophosis, which designates a total loss of hearing. Hearing loss should also not be confused with hyperacusis, which is hypersensitivity to surrounding sounds.

The characteristics of hearing loss vary from case to case. This hearing disorder is generally defined qualitatively and quantitatively.

Qualitatively, hearing loss can be described as follows:

• unilateral or bilateral, when it concerns one or two ears;
• homogeneous or heterogeneous, when it affects all sound frequencies in the same way, or only certain frequencies;
• with the presence or absence of sound distortions, which correspond to deformations of sounds.

From a quantitative point of view, deafness during hearing loss can be considered as:

• mild deafness, with a loss between 20 and 40 dB;
• moderate deafness, with a loss between 40 and 70 dB;
• severe deafness, with a loss between 70 and 90 dB;
• profound deafness, with a loss between 90 and 120 dB.

There are many explanations for hearing loss. Depending on the origin of the hearing loss, it is possible to distinguish several types:

• transmission hypoacusis, or conductive deafness, which reflects a problem in the transport of sound;
• perceptual hearing loss, or sensorineural deafness, which results from a problem in the analysis of sound;
• mixed hearing loss, or mixed deafness, which concerns both the transmission and the perception of sounds.

These different types of hearing loss are the result of damage to the ear. Several structures can be affected: the outer ear, the middle ear and the inner ear.

Causes of hearing loss related to the outer ear

Mixed hearing loss, or transmission, may be due to damage to the outer ear:

• a plug of earwax, which causes obstruction of the ear canal;
• the presence of a foreign body ;
• a otitis externa, that is, diffuse inflammation of the external auditory canal;
• an osteoma of the external auditory canal, which corresponds to the formation of bone growths;
• a tumor of the external ear canal ;
• un head trauma, that is to say a shock at the level of the skull, the intensity of which can in particular cause a fracture of the tympanal bone at the level of the ear.

Causes of hearing loss related to the middle ear

Mixed hearing loss, or transmission, can also be caused by damage to the middle ear:

• serous otitis, that is, inflammation of the lining of the middle ear that lasts for more than two months and causes fluid effusion;
• a acute otitis media, that is to say an acute inflammation of infectious origin in the cavities of the middle ear;
• perforation of the eardrum, which is often the consequence of trauma or infectious otitis;
• damage to the ossicles of the middle ear, especially in the event of fractures, dislocation or malformation.

Causes of hearing loss related to the inner ear

Mixed hearing loss, or perception, can be the consequence of damage to the inner ear:

• sound trauma, that is to say a sudden exposure to sounds of too high intensity;
• head trauma ;
• sudden deafness, that is to say sudden sensorineural deafness which is generally caused by inflammation of viral origin and associated with stress;
• acute labyrinthitis, which is an inflammation of the inner ear;
• taking ototoxic drugs, that is, the use of substances that impair hearing functions;
• presbycusis, which corresponds to the aging of the organ of hearing;
• congenital deafness, which corresponds to deafness present from birth.

In many cases, treating the cause of the hearing loss will make the hearing loss go away. However, in some cases, it can become permanent. Sometimes severe forms of hearing loss can occur. Usually linked to an injury to the inner ear, the latter require rapid medical treatment to limit the risk of sequelae.

Treatment involves treating the cause of the hearing loss. Depending on the origin diagnosed, treatment may for example be based on:

• taking anti-inflammatory drugs,
• the use of antiplatelet agents;
• the establishment of oxygen therapy.