Hearing screening following treatment of neonates in NICU

Background: Advances in perinatal medicine have increased the survival rate of infants admitted to neonatal intensive care unit (NICU). Many perinatal conditions may also cause hearing impairment. Early detection of hearing loss by screening and appropriate intervention are critical to speech, language and cognitive development. The aim of this study was to determine the rate of hearing damage in neonates admitted to NICU in Amirkola Children's Hospital, Babol, Iran.
Methods: This is a prospective cross-sectional, descriptive analytic study, carried out from March 2003 to April 2004. 330 neonates were screened first by Transient Evoked Otoacoustic Emissions (TEOAE) (Echocheck, Otodynamics Ltd, England), and if failed, by Auditory brainstem response (ABR) (Bera 2 Hortman Version, Beyer Dynamic Dt-48, Germany). ABR was performed with 40 db hearing level click stimulus to each ear. Data was analyzed by SPSS software using T-test and Fisher exact test.
Findings: 58% of 330 NICU patients were born preterm and the rest in term. 24 neonates (7.3%) failed on TEOTE test and were referred for ABR. Before ABR testing 8 neonates died and 4 neonates had conductive hearing loss (otitis media). Finally 7 (2.1%) developed permanent hearing loss.
Conclusions: Findings of this study showed that 7.3% of NICU patients failed on TEOTE and 2.1% had permanent hearing loss on ABR examination. Based on these findings, we recommend hearing screening of high risk neonates admitted to NICU.