Around 2 to 3 out of 1,000 newborns are born with hearing loss that requires treatment. This makes hearing disorders the most common congenital sensory impairment. However, effective treatment methods are available. As a result, congenital hearing loss that is detected early can usually be compensated for well.
Treatment should take place as early as possible. Only then can the physiological phases of auditory pathway maturation and spoken language development be optimally utilized.
The consequences of a hearing impairment that is not treated in time are, depending on the degree of the hearing impairment
- limited or no spoken language development and
- cognitive, emotional or psychosocial disorders.
Early detection therefore plays a key role in the treatment and (re)habilitation of congenital hearing loss. Newborn hearing screening is therefore of great importance.
Without early diagnosis, hearing disorders requiring treatment are usually only discovered at the age of two and a half years or later. For this reason, there is now a comprehensive early detection program and a tracking system.
In 2004, the first suspicion of a hearing disorder came at an average age of 27 months. Specialist confirmation was available at the age of 36 months. Minor or unilateral hearing impairment is often first detected at the school entry examination.
In many cases, it is several months before therapy begins. In 2004, therapy began on average at the age of 38 months. As a result, treatment often only began after the optimal therapy window had passed.
Without newborn hearing screening, hearing disorders are generally detected too late. For example, only when parents notice that their child speaks less or worse than others.
However, healthy hearing is a prerequisite for many developmental processes, especially for normal spoken language development!
The later a hearing impairment is detected and treated, the more serious its effects. Early treatment can ensure that the child has the best possible start to speech development.
A painless hearing test can reliably detect hearing disorders in the first few days after the child's birth. An automated measuring device is used for this purpose
Universal newborn hearing screening was introduced in Germany in 2009. This represents a decisive step towards the early detection and early treatment of childhood hearing disorders in the first six months of life.
In order to provide optimum support for the implementation of newborn hearing screening, some federal states have set up hearing screening centers. These have the task of accompanying children and parents in what is known as "tracking". The aim is to clarify the child's hearing ability in a specialized paediatric audiology center. If necessary, treatment and support is also initiated here.
Newborn hearing screening is carried out using objective hearing testing methods in the first few days after birth. Automated measuring devices are used. The child is not exposed to any stress.
1 TEOAE = Transient evoked otoacoustic emission (sound emissions from the inner ear):
A small probe is inserted into the baby's ear, through which a rapid series of soft test tones are offered. The normally hearing inner ear then sends soft sounds (otoacoustic emissions, TEOAE) back into the child's external auditory canal. They are registered here with a sensitive measuring probe.
If these emissions are detectable, the middle ear and cochlea are functioning up to the sensitive sensory cells (outer hair cells).
Fig. 1: Baby during TEOAE screening
2nd AABR measurement = Automated auditory brainstem response (responses of the brainstem to sound stimuli):
In this measurement method, the baby is also presented with quiet sound stimuli via the probe. Three small electrodes record and evaluate the nerve impulses triggered in the area of the auditory nerve and the lower brainstem.
This makes it possible to check the auditory system above the sensory cells of the cochlea in the area of the auditory nerve and the brain stem. If these stimulus responses can be reliably detected, the
- Middle ear,
- cochlea,
- auditory nerve and
- the lower sections of the central auditory pathway at brain stem level
are functional. These signals are referred to as AABR. It is therefore the safest hearing test method that can be used at this time.
Fig. 2: AABR measurement in the newborn
Newborn hearing screening is carried out in the birthing facility in either one or two stages.
Two-stage hearing screening:
- Stage 1: TEOAE: for healthy newborns
- Stage 2: AABR: for all children at risk and all children with abnormal TEOAE results
TEOAE is measured in healthy newborns. If this measurement is repeatedly abnormal, it is checked by an AABR measurement.
The AABR measurement is always carried out for all children at risk. High-risk children are, for example, babies with intensive medical care or additional illnesses. These children may have an increased risk of a disease in the area of the auditory nerve and brain stem.
One-stage hearing screening:
- Stage 1: AABR in healthy newborns and children at risk
The AABR measurement is carried out on all newborns, regardless of whether they were born normally or have risk factors.
Both tests are easiest and quickest to perform when the baby is asleep. They are not painful and have no side effects.
If the result needs to be checked, you should not allow too much time to pass. The child then needs a professional follow-up examination in a qualified facility as soon as possible.
The screening device displays its results in the form of the statement: "normal" or "needs checking". If "normal" appears on the screen, everything is fine. If "in need of control" appears, there is a need for a control examination at the birth center. If there is a need for a check-up on discharge from the hospital, the baby needs a professional check-up in a qualified pediatric audiology facility as soon as possible.
Parental consent Screening ID for hearing screening
Parents are informed at the birthing center, both by the staff and by means of written information for parents.
The parents must first consent to the hearing screening and/or data storage, taking into account all data protection regulations. The examination is then carried out using the above-mentioned objective hearing testing methods. The test result is documented in the yellow examination booklet and transmitted to a hearing screening center if there is cooperation.
Children who show an abnormal result in the first stage of hearing screening (primary screening) are initially given a repeat test (TEOAE, AABR) in the same facility as the second stage of hearing screening up to U2.
If this result is also abnormal on discharge, further diagnostics are required in a timely manner. According to legislation, this detailed diagnosis should be completed within the first three months of life.
Tracking by the hearing screening centers
Named tracking is organized at hearing screening centers, provided the birth facility is connected to a center. Tracking refers to the follow-up of children who have failed the test or have not been screened.
Every day, the data of all connected screening birth centers and follow-up centers are transmitted to the tracking center. The data transfer of personal, measurement and measurement quality-relevant data takes place directly from the measuring device.
Once parents have given the necessary consent, the hearing screening center sends them multiple reminders of the outstanding examinations. Tracking thus helps to ensure that all children receive a professional follow-up examination in a timely manner.
Unfortunately, hearing screening programs without tracking are characterized by a high "lost-to-follow-up" rate of up to 50 percent. This refers to children who are no longer professionally followed up despite a newborn hearing screening result that needs to be checked.
Only well-organized tracking can ensure that hearing-impaired children can be identified and cared for at an early stage.
Follow-up examination in the event of an abnormal hearing screening result
If the test result needs to be checked, parents receive information about the next point of contact and the next steps.
You can also obtain the addresses of qualified follow-up examination centers at all known locations, e.g. from your pediatrician or ENT specialist.
The follow-up of the hearing screening can be organized in two stages:
- Follow-up stage 1: As part of a screening consultation, a further hearing screening is repeated using an AABR measurement and an ear microscopy is carried out. If necessary, further diagnostic measures are used (e.g. tympanometry for objective testing of middle ear function).
- Follow-up stage 2: If the abnormal hearing screening result is confirmed, a detailed pediatric audiological differential diagnosis is required in a second stage. This is where a reliable diagnosis of the type and degree of possible hearing loss is made. This lays the decisive foundation for further treatment steps.
Of great importance is the constant quality control and quality assurance
- of the hearing screening programs and
- the "follow-up"
by the hearing screening centers. To this end, regular completeness and quality checks of screening and follow-up are carried out by the hearing screening centers.
Central tasks of the hearing screening centers are also
- Training and ongoing support of the screening staff,
- the selection of measuring devices and procedures and
- the organization of the confirmation diagnostics in the follow-up facilities.
This is the only way to ensure that children who are hearing impaired from birth are identified and given early treatment and habilitation.
