Auditory screening in high risk neonates: selection of a test protocol

As part of a programme evaluating evoked oto-acoustic emissions (EOAE) as a screen for hearing impairment in graduates of a neonatal intensive care unit (NICU), a detailed study has been carried out on 250 infants to determine the best test protocol. EOAE and air conduction auditory brain-stem response (ABR) tests have been carried out on all infants and bone conduction ABR on air conduction ABR failures. Screen failure rates were not dependent on age when tested but were affected by gestational age if the infant was tested before discharge. Coverage was 98% for infants tested before discharge but was 81% for infants tested as outpatients at a mean age of 47 weeks (post-conception). Consideration of different test protocols and the shorter test time for the EOAE test led to the conclusion that, where large numbers are involved, the most cost-effective method is to screen initially by EOAE. Failures would then be re-tested before discharge by ABR.