Background:
The World Health Organization (WHO) reported in 2013 that approximately 360 million people have disabling hearing loss, of which 32 million are children. A major consequence of hearing loss is a disability in communication: development of spoken language is often delayed in children with hearing loss, or absent in total deafness. Such children can benefit from a range of interventions such as hearing aids, cochlear implants, and educational and social support. Hearing screening can prevent the most severe consequences of hearing loss, but it is preferable first to consider populations with a high probability of developing hearing impairment. The present study assessed the incidence of hearing impairment through ABR in infants at high risk at Casa Sollievo della Sofferenza Hospital in southern Italy.

Material and Methods:
The paper reports the results of auditory brain stem response (ABR) testing over a period of 3 years on infants born with a history of infantile respiratory distress syndrome (IRDS), otoacoustic emission failure at hearing screening, low birth-weight (<1800 g), family history of deafness, hyperbiluribinemia, premature birth, congenital infection (cytomegalovirus), or craniofacial anomalies.

Results:
Of 549 infants tested, 469 (85.4%) showed normal hearing, 51 (9.3%) suffered mild hearing impairment, 6 (1.1%) had moderate hearing impairment, 8 (1.5%) had severe hearing loss, and 15 (2.7%) failed to show any response at maximum intensity levels in both ears. For the hearing loss categories, the most important risk factors were found to be (in order of importance): craniofacial malformation, CMV infection, and familial factors.

Conclusions:
ABR is an important clinical tool in the identification and quantification of hearing impairment. In neonatal screening it is preferable first to consider populations with a high probability of developing hearing losses.