Long-termoutcomeofneonatalhyperbilirubinaemia:subjective andobjectiveaudiologicalmeasures B. O È G Æ U È N,  B. S ËERBETC ËIOG Æ LU,  N. DUMAN, y H. O È ZKAN y & G. KIRKIM  Departments of  Otorhinolaryngology, Hearing, Balance and Speech Section and yPaediatrics, Dokuz Eylu Èl University, Medical School, I Ç zmir, Turkey Accepted for publication 6 May 2003 O È G Æ U È NB ., S ËERBETC ËIOG Æ LU B ., DUMAN N ., O È ZKAN H . & KIRKIM G . (2003) Clin. Otolaryngol. 28, 507±513 Long-term outcome of neonatal hyperbilirubinaemia: subjective and objective audiological measures Neonatal hyperbilirubinaemia is a common cause of early onset sensorineural hearing loss. There is no exact method to detect the extent of the neurotoxicity of bilirubin. On the other hand, the auditory pathway is known to be one of the most sensitive parts of the central nervous system (CNS) to this toxic agent. This prospective follow-up study was performed to evaluate and compare the factors related to the hearing of neonates with severe hyperbilirubinaemia and an age-matched control group. Both of these groups were tested using auditorybrainstemresponse(ABR)aswellasevokedotoacousticemissions.Additionally,bothofthesegroupsof children were evaluated subjectively using an early speech-language-communication evaluation questionnaire. There was no signi®cant difference in either objective (ABR and evoked otoacoustic emission) or subjective assessment (questionnaire) between the study and control groups. Furthermore, no correlation between serum total bilirubin levels and ABR latencies or thresholds was found within the study group. Keywords hyperbilirubinaemia neonatal/bilirubin toxicity/otoacoustic emissions/evoked potentials auditory - brainstem/speech perception Neonatal hyperbilirubinaemia has long been recognized; however, little information is available about the distribution ofbilirubinwithinthecentralnervoussystem(CNS)aswellas the extent of its toxic effects on auditory neural pathways. 1 Most infants with hyperbilirubinaemia may recover without medical treatment. For many years, bilirubin levels exceeding 20 mg/dL were accepted as a risk factor for kernicterus, and it was an indication for exchange transfusion. 2 Studies that investigated the short-term effects of hyperbi- lirubinaemia on hearing function had indicated that major effects were on auditory neural pathways. 3±5 These evalua- tions were made just before and after phototherapy or exchange transfusion, which were aimed at decreasing the serum bilirubin to safe levels. 6±9 In the literature, there are few studies reporting the long-term effects of hyperbilirubinaemia on auditory neural pathways. The effects of hyperbilirubinae- mia on hearing function, in fact, could be dose dependent and of a progressive nature. Thus, the purpose of this prospective study was to evaluate the long-term effects of neonatal non- haemolytic hyperbilirubinaemia exceeding 20mg/dL level. Materials and methods The study group and the control group comprised 30 children each, whose ages were between 24 and 72 months. The mean age of the study group was 36.6  13.6 months, and of the control group was 38.9  12.2months (Table1). The peak serumbilirubinvaluesreachedameanof6.1  2.5days(range: 3±14days) after birth. The median duration of phototherapy was 3 days (range: 2±6days) for the ®rst readmission. Written informed parental consent was obtained for all tested subjects. Subject selection criteria for the study and control groups, in terms of their neonatal period, were as follows: Study group: 1. Birth weight was 2500g and greater, and gestational age was 37 weeks and greater 2. Negative Direct Coomb's test and non-haemolytic hyper- bilirubinaemia Clin. Otolaryngol. 2003, 28, 507±513 # 2003 Blackwell Publishing Ltd 507 Correspondence: Dr Bu Èlent S Ëerbetc Ëiog Ælu, MD, PhD, Dokuz Eylu Èl Tõp Faku Èltesi KBB ABD, I Ç s Ëitme-Konus Ëma-Denge U È nitesi, I Ç nciraltõ- I Ç zmir 35340, Turkey (e-mail: serbetcioglu@deu.edu.tr).