Question - Answer
How does a person hear?
The human ear has three main parts:
The auricle that helps us determine where the sound comes from.
The auditory meatus serves as an audio channel. It can accumulate earwax.
The tympanic membrane, which is tightly stretched, like the skin of a real drum, and turns sound vibrations into vibrations.
A chain of three small bones, called a hammer, an anvil and a staple, and carry out vibrations into the inner ear.
The inner ear
A snail that is coiled like a real snail and filled with liquid. It contains very sensitive cells called hair cells, because at the end of each cell there is a tiny formation, similar to a hair. Hair cells, hesitating, produce electrical impulses which, through the auditory nerve, enter the brain, which recognizes them as sounds.
A person hears with the brain, not with the ear!
Why are hearing impaired?
1. Conductive hearing loss
2. Sensorineural hearing loss
3. Auditory Neuropathy
4. Centralized hearing disorder
In pediatric surdology, the most common is conductive and sensorineural hearing loss.
Conductive Hearing LossWith conductive hearing loss, changes do not affect the structure of the inner ear and the auditory nerve, but affect the region of the tympanic membrane and middle ear. For example, impairment of mobility in the system of auditory ossicles or extensive trauma of the tympanic membrane. Such hearing impairment in children occurs due to: atresia (complete or partial underdevelopment) of the external auditory canal, sulfur plugs, developmental anomaly and damage to the eardrum and otitis media, otitis etc. Conductive deafness leads to hearing loss of 1-2 degrees.
The hearing aid will help to overcome the damaged area - increasing the pressure of sound. It happens when the damage is so severe that it completely prevents the oscillations, and even the most powerful hearing aid can not help - in this case the doctor chooses between the operation to restore the middle ear or the operation to implant the vibrating implant.
Sensorineural hearing lossWith sensorineural hearing loss, hair cells in the cochlea or auditory nerve are damaged, which is less common. With this kind of hearing impairment in young children, sound vibrations can not be converted into electrical signals, which leads to the impossibility of recognizing sounds by the brain. With a small, moderate or even moderately severe hearing loss, sound will be perceived by the surviving hair cells.
The most common causes of sensorineural hearing loss in children are hereditary hearing impairment, hypoxia, high bilirubin level, viral infections of the mother during pregnancy, meningoencephalitis, ototoxic drugs, etc. Hearing loss - from 1 degree to deafness.
In this case, the hearing aid will significantly improve the partially left auditory function - due to more intense stimulation of the hair cells.
When a significant part, or all hair cells, died - hearing aids are often ineffective. Then a cochlear implant is used which, taking sounds, converts them into an electrical signal, and transfers them directly to the nerve, bypassing the structures of the affected cochlea.
Auditory NeuropathyThis violation is highlighted in recent years due to the emergence of objective methods of hearing research. In contrast to sensorineural hearing loss, it is characterized by the preservation of external hair cells. The main cause is a violation of synchronization of excitation in the fibers of the auditory nerve. Internal hair cells can also be damaged. These patients are characterized by difficulties in speech perception, although hearing loss is usually insignificant.
Conductive and sensoneural hearing loss, auditory neuropathy refer to peripheral hearing impairments.
Central hearing impairmentThese disorders are caused by damage to the subcortical, beginning with the cochlear nuclei, and cortical centers of the auditory system. At the same time, the processes of analyzing acoustic, including speech, signals are detected - detection, discrimination, recognition, recognition, and memorization of sound signals.
Children with central hearing disorders behave as hearing impaired, although they have normal or slightly elevated hearing thresholds. These disorders are especially characteristic for children with pathology of the nervous system caused by hypoxia and hyperbilirubinemia.
Hearing disorders can be one-sided (one ear is damaged - left or right) and bilateral (both ears are damaged).
Violations can be hereditary (including those caused by genetic mutations), congenital, acquired. In 50% of newborns, deafness is of hereditary origin. In a third of these children, hearing disorders are combined with other disorders, that is, they are part of the syndrome. Hearing disorders can be combined with diseases of the eyes, bone-muscular, integumentary, nervous, endocrine systems, kidney diseases. Hereditary hearing loss is more often caused by irreversible changes in the structure of the cochlea, but there are disorders associated with anomalies of the external and middle ear. Hereditary hearing impairments can occur immediately after the birth of a child or develop gradually.
Currently, more than 50 genes have been identified, mutations in which cause various hearing disorders. Most of these disorders are congenital or develop in a child at an early age before mastering speech.
Auditory perception with varying degrees of hearing loss
Depending on the degree of hearing loss, I, II, III, IV degree and deafness are distinguished.
Degree of hearing loss
Mean thresholds of hearing
Perception of spoken and loud speech
Perception of Whisper Speech
2 m– at ear
3 m – at ear
at ear – no
loud speech at the ear
cry at the ear
1. Dealingual deafness is a deep hearing loss since birth or in the first year of life. Children with such hearing impairment can learn speech only with great difficulty and more often use sign language for communication;
2. Perieningual deafness - it includes hearing loss in the period of mastering speech until it is fully mastered (from 1 year to 5 years);
3. Post-lingual deafness - it includes hearing loss that occurs after speech acquisition (late-patient patients).
Why is an audiological screening performed?
The first three years of life the child learns to listen and speak. If the baby does not hear well, he will not understand the speech well or will not be able to understand it at all. Because of this, it is difficult to learn how to speak.
With a deep hearing loss, about 1 child out of 1000 is born. In past years for such a child, the world of sounds and full life would be closed, he would not have verbal communication, social adaptation. Today, there are new opportunities for early diagnosis of hearing and hearing and speech development of children with hearing impairment.
With a timely start of the program, children with low hearing are not much different from their peers. They go to ordinary kindergartens and schools, learn to play musical instruments, learn foreign languages.
However, the assistance program is most effective if it is started in the first months of a baby's life. That's why all newborns must undergo a hearing test right after birth.
How is audiological screening performed?
To test your hearing, a quick, painless and absolutely safe way for the baby's health is used. The hearing is checked on the 3-4 day after the birth of the child by the method of induced otoacoustic emission. The examination is carried out in a dream. In the child's ear a small probe is inserted, through which sound is delivered. A healthy, hearing ear responds with an "echo" to this sound.
Results of audiological screening
n the absence of "echoes" in any case, one can not immediately talk about deafness. The reasons for the absence of "echo" can be:
presence of postpartum masses in the external auditory canal;
diseases of the middle ear;
the presence of a true pathology of the auditory system.
If the "echo" is not registered, then your child should repeat the hearing test at the age of 1 month. in a polyclinic or territorial center of rehabilitation of hearing.