Neonatal Hearing Screening at Neonatal Intensive Care Unit of Assiut University Hospital

Hearing loss is one of the most common congenital anomalies . It has been shown to be greater than that of most other diseases and syndromes (eg, phenylketonuria, sickle cell disease) screened at birth . Data from the newborn hearing-screening programs in Rhode Island, Colorado, and Texas showed that 2-4 of every 1000 neonates have hearing loss.

Early Intervention at or before 6 months of age allows a child with impaired hearing to develop normal speech and language, alongside his or her hearing peers and can prevent severe psychosocial, educational, and language impairment.( One of the most high risk population are neonates who spend time in the newborn intensive care unit, exposed to high frequency ventilation, hyperbilirubinemia, low birth-weight, and exposed to ototoxic medications.

Auditory brainstem response, otoacoustic emissions , and automated Auditory brainstem response testing have all been used in newborn hearing-screening programs. otoacoustic emissions are fast objective, efficient, and frequency-specific measurements of peripheral auditory sensitivity are used to assess response of the outer hair cells to acoustic stimuli. To measure otoacoustic emissions, a probe assembly is placed in the ear canal, tonal or click stimuli are delivered, and the otoacoustic emissions generated by the cochlea is measured with a microphone .

Currently, 2 types of evoked otoacoustic emissions measurements are used for newborn hearing screening: transient evoked otoacoustic emissions and distortion product otoacoustic emissions . Provided that the patient's middle ear function is normal, these measurements can be used to assess cochlear function for the 500-6000 Hz frequency range. The presence of evoked otoacoustic emissions responses indicates hearing sensitivity in the normal to near-normal range .

The Auditory brainstem response test records brainstem electrical activity in response to sounds presented to the infant via earphones. In contrast to the otoacoustic emissions test, the The Auditory brainstem response evaluates the auditory pathway from the external ear to the level of the brainstem, enabling diagnosis of auditory neuropathy, which is a less common cause of hearing impairment .