Newborn Hearing Screening

Newborn hearing screening detects permanent congenital hearing loss in the first weeks of life. Two methods are used: otoacoustic emissions, which measure cochlear outer hair cell activity, and automated auditory brainstem response, which measures neural responses to sound.

Screening is universal in many services, and it is performed before discharge where possible. A referral is made for any infant who does not pass.

Usage. It is used as a universal screen, and it is followed by diagnostic audiology for infants who do not pass.

Indications. Universal screening of all newborns, and screening of infants with risk factors for hearing loss.

Risk factors. Neonatal intensive care stay longer than 5 days, ototoxic drug exposure, family history of childhood hearing loss, craniofacial anomaly, congenital cytomegalovirus infection, and syndromes associated with hearing loss.

Preparation and technique. The infant is screened in a quiet environment, ideally when asleep or settled. The probe is placed in the ear canal, and the device records the response. Background noise and debris in the ear canal affect the result, so the ear is checked before testing.

Contraindications and precautions. Ear canal obstruction, vernix, or amniotic fluid can prevent a valid recording, and the test is repeated when the ear is clear.

Interpretation.

• A pass is a valid response in both ears by the method used.
• A refer result is recorded when one or both ears do not produce a valid response.
• Otoacoustic emissions are absent in cochlear loss, and automated auditory brainstem response shows absent or abnormal waveforms in neural loss.
• A refer result is followed by diagnostic audiology, which confirms the type and degree of loss.

Causes of a refer result. Permanent sensorineural hearing loss, conductive loss from middle ear fluid or debris, ear canal obstruction, and technical factors.

Critical values and findings needing immediate action.

• A refer result in an infant with a risk factor requires prompt diagnostic assessment.
• Bilateral loss requires urgent referral to a paediatric audiology service, since early intervention improves outcome.

Limitations and artefacts. Middle ear fluid and debris in the first days of life can cause false refer results. Screening does not detect every hearing loss, particularly late onset or progressive loss. Background noise lowers the validity of the test.

Follow up tests. Diagnostic auditory brainstem response, audiology assessment, tympanometry, and testing for congenital cytomegalovirus infection where the infant has risk factors.

Special groups. Preterm and neonatal intensive care infants are screened with awareness of their risk factors and may need repeat testing. Infants with craniofacial anomalies are assessed by specialists.