Hearing loss in infants occurs with a frequency of 1-3 in 1000 newborns. It is one of the most common congenital anomalies. If the diagnosis is not made and treatment is not started in the early period, speech problems are also encountered in babies and language development is damaged. In advanced ages, they experience social communication problems, learning becomes difficult, and emotional problems develop.
Detection of hearing problems in the early period allows early intervention. Hearing support can be provided, language development training can be given. Psychological and social adaptation to society is facilitated.
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Types of hearing loss:
- Conductive hearing loss : There is a blockage in the transmission of sound from the outer ear canal to the inner ear. Bone conduction is normal, air conduction is problematic. It often develops due to middle ear infections.
- Sensorineural hearing loss : The auditory nerve and cochlear hair cells are damaged.
- Mixed hearing loss : Both conductive and sensorineural hearing impairment are seen.
Hearing loss degrees:
- Mild: Less than 15-30 dB
- Medium: Less than 31-50 dB
- Heavy: Less than 51-80 dB
- Too heavy: Sounds less than 81-100 dB cannot be heard.
Hearing risk groups in newborns:
- Family history of sensorineural hearing loss, genetically
- Passing TORCH group diseases during pregnancy,
- Craniofacial anomalies,
- Birth weight below 1500 g,
- Advanced jaundice,
- Use of ototoxic drugs such as aminoglycosides, diuretics,
- Bacterial meningitis disease,
- APGAR score of 0-4 in the 1st minute, 0-6 in the 5th minute,
- Mechanical ventilation for more than ten days.
When is newborn hearing screening done?
Newborn hearing screening is done in three stages. The first screening is done within the first 72 hours after birth, the second within 7-15 days after birth, and the last one within 15-30 days after birth.
Screening tests do not give an idea about the type and degree of hearing loss. It simply means whether there is a hearing loss or not. Babies with suspected hearing loss are subjected to further examinations. The procedure is done through a device that is placed on the baby’s head and does not cause pain or discomfort.
At the end of the process, the hearing test passed or failed information is given. Second and, if necessary, third stage tests are applied to the remaining babies.
What are newborn hearing screening tests?
Otoacoustic Emission (OAE): A stimulus of 35 dB is given to the baby. Both ears are asked to give a positive response to the stimulus. It is an inexpensive and quick method, but requires child involvement and trained personnel to implement. It is affected by ambient noise. It does not indicate hearing loss below 35 dB. Therefore, it is less preferred.
Hearing brainstem response (ABR): Indicates hearing loss originating from the auditory nerve. Electrodes are placed on both mastoid bones, on the forehead and on the top of the head. It is an expensive but more effective method. It can show cochlea, auditory nerve and auditory canal problems. It is more preferred for hearing screenings.