Auditory evaluation of high risk newborns by automated auditory brain stem response

ABSTRACT

The objective of this study was to assess the prevalence of hearing impairment by automated auditory brain stem response [AABR] in newborns admitted to an intensive and intermediate care unit and to analyze the associated risk factors. An observational cross-sectional study was conducted between January 2005 and January 2006. 834 newborns [62% boys and 38% girls] were assessed. Newborns had a mean [SD] gestational age of 36 [2.1] weeks with a mean [SD] birth weight of 2950 [1250] grams. The presence of the following neonatal pathologies was investigated craniofacial malformations, hyperbilirubinemia [total bilirubin 20 mg/dl for all newborns], neonatal asphyxia, congenital infections, septicemia, birth weight [meningitis, consanguinity, family history of congenital hearing loss and history of convulsion. Newborns who died before the age of 3 months and whose stay in the hospital lasted less than 48 hours were excluded. Chi-square test was used to identify the risk factors for hearing loss. Out of 834 neonates, 34 [4.07%] had sensory-neural hearing loss. The most common risk factors of hearing loss included hyperbilirubinemia [11%], asphyxia [8%], birth weight less than 1500 g [6%], septicemia [6%], convulsion [2%], and meningitis [1%]. There was a statistically significant association between hyperbilirubinemia [P=0.001], weight less than 1500 g [P=0.002], cesarean section [P=0.005] and impaired ABR results. There was no relation between family history of congenital hearing loss and craniofacial malformation as risk factors for hearing loss. This study showed statistically a relation between hyperbilirubinemia, weight less than 1500 g, cesarean section and impaired AABR results. The most common risk factors of hearing loss were hyperbilirubinemia, asphyxia, birth weight less than 1500 g, septicemia, convulsion, and meningitis