Evaluation of Auditory Brainstem Response (ABR)in neonatal hyperbilirubinemia

ntroduction: Jaundice is a commen prablem in newborns and clinical presentations resulting from early stages of hyperbilirubinemia toxicity. ABR is useful test to recognize the primary brain stem encepholapathy. This study has been carried out with the objective of evaluating the ABR in recognizing hearing disorders in newborns suffering from Jaundice. In this study, we describe ABR obtained in 60 full term newborns, with birth weight more than 2500 gr,and Bilirubin concentration Between 18-54mg/dl without immune hemolysis and hearing disorder risk factor, from march 2005 until January 2006. ABR was carried out before commencing therapy, While first ABR was abnormal, repeated ABR was done after treatment exactly after 3 months. In this study, sixty newborns were evaluated by ABR for detecting early hearing disorder. Mean weight were 3000±250 gr, Gestational age 38±1 weekes, bilirubin concentration 36 mg/d.l±9 (18-54 range).17 patients had abnormal ABR pretreatment, and 12 patients done normal ABR second evalution after treatment (Bili: 26±3), 5 patients had persistent abnormal (mean Bili: 43±5). ABR abnormalities includes latencies wave I,III,V and loger duration interpeaks I-V,I-III and III-V. (Mean values of ABR latencies when compared with a group of normal babies as a control group were significantly increased before treatment, but returned to normal value after treatment (P=0.001). Our study proved that newborns with serum bilirubin ranging from 18 to 54 mg/dl would be increase in ABR waves I,III,V and also increase in interpeak I-III,III-V,I-V that may be irreversible in those infants with bilirubin more than 32 mg/dl.