LAUSR

T he world prevalence of congenital hearing loss is 1/1000 live births and is higher (2% to 4%) in children with some risk factor. The diagnosis of hearing loss is based on subjective (audiometry, with an adequate technique for the child’s age) and objective tests (otoacoustic emissions and electrophysiological assessments). They help to define the degree and type of the auditory impairment, as well as the topography of the lesion, which is crucial in establishing prognosis and therapeutic measures. In cases of neonatal hearing loss, early identification is extremely important so that early rehabilitation can be achieved thus avoiding repercussions during the acquisition of speech and language, cognition, school performance, and socialization. For this early identification, neonatal hearing screening is essential. The most used method in performing the screening has been the otoacoustic emissions test, which is a fast and harmless test capable of accessing the auditory peripheral organ function, but, as any other screening test, has a quite high false positive rate, and must be confirmed by diagnostic tests. So, for children with risk factors from hearing loss, neonatal hearing screening should be performed using an electrophysiological examination, auditory brainstem response (ABR), as this population would have a greater risk of auditory neuropathy that is not identified by otoacoustic emissions. Ideally, all children should be submitted to hearing screening within the first month of life and, up to 3 months of age, children with a hearing loss diagnosis should be identified so that the appropriate intervention in each case can be performed up to 6 months. Imaging methods, such as high-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI), are often useful in determining the etiology and topography of the neonatal hearing system damage. Developmental defects affecting the sensory organ, cochlear nerve, brainstem, or auditory cortex can be present in deaf children. T2-weighted MRI or HRCT are the best options for inner ear malformation diagnosis. The first method is also indicated for the study of nerves, with different denominations depending on the equipment, such as FIESTA (fast imaging employing steady-state acquisition) for GE Medical Systems, CISS (constructive interference steady state) for the Siemens product and FFE balance in Philips equipment. It has also been considered the best sequence for cerebrospinal fluid (CSF) cisternography for the visualization of cranial nerves at the base of the skull. The T1 acquisition of a damaged 3D gradient of high resolution (SPGR) is also very useful for visualiza2,3