Hearing is a sense that is developed at birth, hence already during foetal life, in the womb, the child is able to perceive sounds. During the first year or so, development progresses thanks to sounds - both in terms of understanding words, making sounds up to the development of speech, but also from a motor and coordination point of view, when sounds provide a stimulus for the child to take action. Hearing disorders can therefore have an adverse effect on a child's development.
Table of contents:
- Hearing development
- Hearing disorders
- Worrying symptoms
- So what elements of a child's behaviour are worth paying attention to?
Hearing plays an important role in our lives: it is the sense that enables us to perceive sounds from the world around us over a wide range of frequencies (from 16 to 20 000 Hz and from 0 to 120 decibels). This range can vary with age and, in line with developmental patterns, tends to narrow, hence as a child we are able to hear more high-frequency sounds. By far the best audible range is between 1000 and 3000 Hz, i.e. the middle frequencies. All sounds and noises reach us either through the air or through the bony pathway - in the outer and middle ear, there is a process of conduction of the sound collected by the auricle and directed to the ear canals. The sound wave's energy vibrates the eardrum, which is then transmitted to the ossicles and finally reaches the inner ear - the cochlea - where it is picked up and converted into an electrical impulse. The further path of the 'processed' sound follows the auditory nerve to the nerve centres in the brain, where a signal about the received impulse is generated - we hear, i.e. have an impression of sound [1].
Development of hearing
Ear primordia are formed as early as the 2nd month of foetal life, and the inner ear is formed around the 4th or 5th month, so in fact from the 7th month of foetal life hearing begins to function and the foetus begins to perceive sounds, such as the mother's heartbeat or sounds and noises associated with the workings of the intestines, the sound of blood or other noises from the environment. Responses to noise and to pleasurable sound sensations emerge [2].
At birth, hearing is a developed sense and the baby shows reactions to sound stimuli - stopping, closing the eyelids, interrupting sucking or searching with the eyes for the source of the sound. Each day hearing gets better and better and should be supported by reading, singing or listening to sounds from nature.
At the end of the first month of life, hearing is well developed, but the newborn baby does not yet have the ability to recognise sounds; it is only in the second month that a response to the surroundings and attempts to make sounds on his own appear. 3. one month is a clear response to a clap, and in the following month attempts are made to turn the head towards the source of the sound. 5. and 6. month is the beginning of babbling and the emergence of interest in toys that make sounds. The baby gradually begins to recognise words and eventually starts to respond to his name. Around the 10th month the baby reacts to commands, understands simple requests and follows them, and moreover this is the time when listening to music gives the child a lot of pleasure. Around the age of 1 year the baby says his first words. This whole pathway shows that normal hearing determines the normal development of the child, and that any disturbance of hearing can become a cause of stunted development or disorders within the child [2].
Achild's hearing test, photo: panthermedia
Hearing disorders
As hearing damage can occur in different places, different types of hearing loss are referred to.
Precocious hearing loss is closely linked to any abnormalities and pathologies that occur in the outer and middle ear, as these structures are responsible for conducting the impulse that is sound to further parts of the auditory pathway.
Sensorineural hearingloss, on the other hand, can be a consequence of damage to either the structures of the inner ear, the auditory nerve or the centres in the brain responsible for the correct process of sound perception.
If the situation indicates that conductive and sensorineural disorders are present at the same time, mixed hearing loss is a very likely consequence.
There is also the concept of central hearing disorders, which occur as a result of abnormalities in the central part of the auditory system.
These cases are not age-specific and can occur at any stage in a child's life, whether due to a specific genetic predisposition, congenital abnormality or acquired hearing loss, as the aetiology is very complex. Some of the disorders may be temporary and others permanent, but they always relate to a reduction in the child's quality of life associated with the hearing impairment, which may result in developmental or school-related problems in older children [1].
Worrying symptoms
As mentioned earlier - hearing problems in a child can occur at any age and at any developmental stage. Often, a hearing problem goes unnoticed for a long time, which can have disastrous consequences and prevent 100% restoration of normal function.
The impact of hearing impairment on a child's development is very significant and is associated with disruptions to normal functioning - concentration problems, learning difficulties, speech development disorders (which are often attributed to parenting problems).
So what elements of a child's behaviour are worth paying attention to?
Any limitation in speech development should be of concern to the carer, as should the small vocabulary used by the child. Reading comprehension, which comes with increased difficulty for children with hearing loss, is very important. Slurred speech, imprecise pronunciation of words, words without beginnings or endings should also draw the caregiver's attention to consider hearing impairment. The consequence of abnormal sound perception also becomes problems with writing, as what and how the child hears is transferred onto paper. Watching a speaker's face, inability to focus, distraction, and failure to follow instructions can also be signs of hearing loss - whether at home, with a carer, or at school during lessons. Often children with hearing loss ask to repeat themselves, ask questions ("what?"), have difficulty understanding the content of a question and are therefore often unprepared for class or do not complete their homework. When at home, it is also worth paying attention to the child's distance from the television set or "playing" with the volume, keeping a distance when speaking to the child - does the child move to hear what is being said, does the distance from the sound source remain the same. Sometimes a child with a hearing impairment has difficulty locating the source of a sound and speaks very loudly themselves. Sometimes the reaction to noise is to run away, which in turn may suggest a hypersensitivity to the sounds heard, or conversely, the child talks about hearing sounds that are inaudible to others (such as humming, squeaking or ringing). Sometimes these disorders are accompanied by headaches associated with dizziness and imbalance [1].
