Introduction
The sensory perception of hearing is an important component for children to build and learn human language. Hearing impairments should be adequately treated as soon as possible, since all types of hearing impairment can pose great dangers to the child’s linguistic development.
Frequency
In Germany about 500,000 children suffer from a hearing disorder requiring treatment. One to two in every 1,000 newborns have a relevant hearing loss. There are about 7,000 to 8,000 severely hearing impaired children and up to 150,000 moderately hearing impaired children. About three percent of all school children suffer from mild hearing loss.
Types of hearing loss
The hearing disorder can be classified according to anatomy, causes and severity. Anatomically the hearing can be roughly divided into: The special arrangement of the eardrum and the ossicles causes a pre-amplification and impedance adjustment of the acoustic resistance of the air to the acoustic resistance of the inner ear liquids. If this were not done, the sound signal would directly hit the fluid-filled spaces of the cochlea and cause a reflection of the sound energy.
These sound waves could then no longer be used for the actual hearing process. The inner ear is responsible for converting the mechanical energy of the sound waves into bioelectric nerve impulses. These impulses reach the brain stem via the auditory nerve, where the nerve impulses are processed.
Then they reach the audiological cortex, where sound and noise sensation, sound and word comprehension, acoustic attention and storage of word, music and speech content are processed. In hearing disorders, these anatomical structures can be disturbed individually or in combination. There are sound conduction disorders (disorders of sound transmission in the outer ear or middle ear) and sound sensation disorders (the absorption and transformation of stimuli in the area between the stapes footplate and the first neuron of the auditory nerve is disturbed).
Disturbances in the transmission, processing and perception of stimuli can also occur. Various tests are needed to assess the severity of the hearing disorder. Sound audiometry is particularly important, but also the ability to understand one’s counterpart in conversation and the limitations reported by the patient to the doctor play a role in the overall assessment.
You can find a table of the severity classification here.
- The outer ear (pinna and auditory canal) has the task of transmitting the sound signal to the eardrum.
- The eardrum is considered the border between the outer ear and the middle ear. This is where the sound signal is converted from airborne sound to structure-borne sound.
- The middle ear consists of the ossicles hammer, anvil and stirrup. Structure-borne sound is transmitted to the inner ear.
