For every 1,000 births, an average of two children are born with a hearing disorder. Problems with hearing can greatly affect a child’s development. Newborn hearing screening was introduced in Germany to assess hearing abilities at an early stage.
What is newborn hearing screening?
Newborn hearing screening is an early detection examination to diagnose hearing disorders in newborns as early as possible. Newborn hearing screening is an early detection test to diagnose hearing disorders in newborns as early as possible. Hearing disorders can massively hinder the development of children. Only a child who hears normally has the chance to learn to speak normally. Emotional development, the ability to communicate, readiness to learn and learning success depend on the ability to hear perfectly. Deficits in hearing in infancy and early childhood can cause developmentally disabling consequences in personal and professional development for life. Hearing enables the child to differentiate his or her environment from the first day of life. Hearing is the basis for all language development and thus for later abilities to read and write. Hearing disorders are in rare cases congenital. However, they can also be triggered by diseases. If a hearing disorder is detected by newborn hearing screening, it can be corrected even in young children using modern hearing aid technology. The screening ensures that children affected by hearing deficits have an easier start in life.
Function, effect and goals
Newborn hearing screening is performed in the first days of the child’s life at the birth clinic. The screening is not associated with any impairment or pain for the child. The test can be performed even on a sleeping child. The newborn does not have to actively respond to any stimuli. Today, there are two measurement methods that can be used to determine hearing deficits. One method is based on the measurement of otoacoustic emissions (OAE). This measurement method takes advantage of the human ear’s ability to not only receive sound, but also to emit sound. For newborn hearing screening, a tiny probe is placed in the external auditory canals of the ears and emits soft clicking sounds. The vibrations of the clicking sounds are transmitted to the structures of the inner ear. The sound irritates sensory cells in the inner ear. The neonatal test takes advantage of the fact that the sensory cells send back an echo of the sound waves they receive. These vibrations are registered by the probe in the external ear canal, which also has a small microphone installed to pick up sound waves from the inner ear. The strength of the vibrations is measured. If the sound waves from the inner ear are absent or only very weak signals are registered, this may indicate an existing hearing impairment. If the measurement results indicate disturbances in the transmission of sound to the sensory cells, this does not necessarily mean that a pathological condition is present. The measurement should be repeated some time later. Background noise, fluid in the middle ear due to inflammation, or if the child is very restless during the measurement may falsify the test results. Another approved method of newborn hearing screening, where no activity is expected from the child, is called brainstem audiometry. This is a special form of an EEG. This procedure tests the activity of the auditory nerve during the transmission of acoustic stimuli. Each function of nerves in our organism causes a measurable electrical activity. During the test, small measuring electrodes are attached to the newborn’s head. Also in this procedure, clicking sounds are emitted through the external auditory canal with a probe. The electrodes can be used to measure the electrical activity in the transmission of the sound waves of the auditory nerve from the inner ear to the auditory center in the brain. If measured values are outside the normal range, this can be taken as an indication of a possible hearing loss. The child should also sleep as much as possible during this method of measuring hearing ability. The more restless and active a person is, the more the brain, central and peripheral nervous systems produce electrical signals.In the sleeping state, it is easier to assign the signals to the activity of the auditory pathway from the ear to the brain.
Risks, side effects and dangers
If a hearing deficit is detected by newborn hearing screening, performing both measurement methods can help assign which area of the auditory system is the cause of the deficit. While OAE indicates damage to the sensory cells in the inner ear, brainstem audiometry reveals problems in the auditory pathway and thus the auditory nerve. This distinction is important for prescribing the appropriate hearing aid. However, negative test results, if detected in the first days after birth, should not be overestimated. It is not necessary to conclude a hearing impairment from these readings outside the norm. On the other hand, even inconspicuous measurement results are no guarantee for an unrestricted hearing ability of the child. Experience with newborn hearing screening has shown that quite a number of children stand out due to abnormal measurement results. Only a very small percentage of the children tested with negative readings actually suffer from a hearing disorder. Nevertheless, the screening should be an indication to pay more attention to the hearing ability of the new citizen. When the first conspicuous findings are revealed by the test, both measurement procedures, the OAE and the brainstem audiometry, should definitely be carried out. The measurements should be reviewed after some time with retesting before further treatment is given.
