Hearing, a very important function of our body, not vital, but that we use on a daily basis. We can consider that our ear is only the tip of the iceberg, and when it comes to the auditory system, there is a whole part hidden inside our head, which plays a primordial role.

Our hearing system is made up of 3 parts called:

• the outer ear, the one we see, made up of the pinna and the tympanum,
• the middle ear with the three ossicles
• and the inner ear, filled with fluid from which the nerves go to the brain.

The ear is the organ of sound perception and balance. The ear combines a function of perception intended to capture sounds, and a transmission function to transmit these sounds to the brain. Each part of the auditory system has a specific role in the hearing process.

Outer ear

The outer ear collects sound vibrations and directs them towards the eardrum. She is composed :

• the pavilion (where we place our earrings), which captures sound waves and directs them into the external auditory canal;
• from the external auditory canal, this small pipe that is cleaned with cotton swabs; is the conduit through which sound waves pass. It is lined with hair and contains glands secreting earwax whose role is to retain dust. When the earwax is too important, it can clog the duct and it is then necessary to consult your doctor who uses a bulb of hot water to remove the plug. This being a painless manipulation;
• of the eardrum, this membrane located at the end of the ear canal vibrates under the effect of sound waves. The eardrum is very fragile and can be pierced by too loud sounds, by a blunt object or by water pressure during scuba diving. When the one is pierced, it cannot be repaired.

Middle ear

This first visible part extends inside the skull by a second part called the middle ear.

This extends from the eardrum to the oval window and the round window. (see ear anatomy). This air-filled cavity communicates with the pharynx through the duct of the Eustachian tube. The middle ear houses a chain of ossicles (hammer, anvil, stirrup) linked together by their joints, held to the eardrum cavity by ligaments and muscles. The middle ear ensures the mechanical transmission of sound vibrations from the eardrum to the inner ear and their amplification.

Inner ear

Finally the third part is called the inner ear. It is thanks to her that we have balance. It communicates with the middle ear through the oval window. It is divided into several parts:

• the vestibule and the semicircular canals, which are involved in balance and posture;
• the cochlea, which is a tube coiled on itself whose base, organ of Corti, is lined with sensory cells, called hair cells because they have cilia. There are about 15 of them, and their role is essential in the processing of sound information by the brain. It is the setting in motion of the eyelashes thanks to sound waves that generates the formation of a nerve message transmitted by nerve fibers from the auditory nerve to the auditory areas of the brain.

Prolonged exposure to a high volume of sound may cause their alteration, partially or totally. Once damaged, these cells do not regenerate. This is why it is important to place earplugs for extended periods at high sound levels: concerts, work… because hearing loss is permanent.

Our pavilion picks up sound and directs it through the external auditory canal to the eardrum. This vibrates and these vibrations are transmitted to the oval window by the ossicles which amplify the sound message. These vibrations are thus propagated in the inner ear to the cochlea. (snail-shaped).

The cochlea transforms sound into an electrical signal transmitted to the brain through the cochlear nerve. Inside the cochlea, hair cells are suspended in a fluid called endolymph. With the vibrations, the liquid moves and sets in motion the cilia of the cells. The movement of the eyelashes releases messengers (neurotransmitters) which transmit a nervous message through the cochlear nerve: this is called sound information.

There are therefore different types of deafness depending on the part of the hearing system that is dysfunctional. If the obstacle is located in the outer or middle ear (otitis, earwax plug, it is conductive deafness that can be corrected or improved by medical treatment (drops to liquefy the plug or antibiotics for it). ear infection) or surgery.

In children, hearing loss can have two origins: an acquired origin (a sound trauma) or a congenital origin (heredity), conductive deafness.

Congenital causes

Among the congenital causes there are several possibilities

• Hereditary genetic causes such as Branchio-Oto-Renal syndromes, Stickler’s syndrome, Waardenburg’s syndrome, Usher’s syndrome, Refsum’s disease, or even a biotinidase deficiency;
• Premature birth;
• In utero infections (rubella, syphilis, toxoplasmosis, etc.);
• A lack of oxygen in utero or at birth (hypoxia).

Other causes of deafness

Deafness can also be caused in adults by trauma, sensorineural hearing loss, due to sequelae of the inner ear. Frequent at concerts with too high a sound level, or nightclub parties. Compensatory solutions exist: hearing aid, cochlear implant.

When the person has suffered too high a decibel level for a long time, they can also develop tinnitus (very common in hearing loss, especially perceptual). These incessant sounds in the ear can cause migraines, lack of sleep, irritability, depression. In this case, sophrology, meditation, reflexology can be a good help for the person to relax despite the sounds and to accept them rather than to struggle, which amplifies the notion of discomfort.

In the elderly

In the elderly, deafness is linked to the aging of the hair cells in the inner ear, which begin to die. It happens to everyone. But some people lose their hearing and experience hearing loss earlier and faster than others. Age-related hearing loss is also called presbycusis.