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 out-patients 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. Where numbers are small then ABR alone would be used. Follow up would be by ABR rather than EOAE as this gave a lower failure rate and threshold can be measured. Bone conduction ABR was found to be a feasible test in routine use allowing differentiation between conductive and sensorineural losses.
Webb
H D
HD
Department of Medical Physics and Clinical Engineering, Royal Hallamshire Hospital, Sheffield, UK.
Stevens
J C
JC
D005072:Evoked Potentials, Auditory; D006311:Hearing Disorders / Q000175:diagnosis*; D006320:Hearing Tests / Q000379:methods*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007363:Intensive Care Units, Neonatal; D008403:Mass Screening; D012307:Risk Factors