Predischarge screening of very low birthweight infants by click evoked otoacoustic emissions

To evaluate the role of transient evoked otoacoustic emission (TEOAE) in screening very low birthweight (VLBW) neonatal intensive care unit (NICU) graduates for hearing loss in comparison with visual reinforcement orientation audiology (VROA) at 10 months.

The study population was all VLBW neonatal survivors discharged from a single regional NICU at John Hunter Childrens Hospital (JHCH), Newcastle, New South Wales, Australia, between April 1994 and March 1996. A TEOAE screen was performed prior to discharge and repeated if necessary until a pass was obtained in at least one ear. Infants were further screened by VROA at their local Australian Hearing Services (AHS) office at 10 months corrected age. Repeated TEOAE failures were referred directly for an ENT opinion.

A total of 193 infants were eligible for enrolment during the study period. One hundred and forty-four (75%) received TEOAE testing. The median age of first screen was 36 weeks gestational age. Ninety-five (66%) of infants tested passed on a single screen. Of the remaining 49 infants, 26 passed on retesting (overall pass rate 84%). Twenty-three (16%) were deemed to have failed the TEOAE screen. Of the 121 infants who passed TEOAE, only 67 (55%) completed VROA. Two of these infants have a high frequency sensorineural loss and one of them has been aided. In the 23 who failed TEOAE, nine have subsequently had normal VROA, another, though not tested is clinically normal. three have hearing loss with middle ear disease and eight have confirmed sensorineural deafness, all aided. One infant has died and an infant with Down's syndrome has been adopted out of the area. It is of interest to note that the eight aided infants are all of less than 28 weeks gestation. If we restrict analysis to infants with completed VROA testing, the TEOAE has a 97% negative predictive value for sensorineural deafness and a 38% positive predictive value.

This study has highlighted both the prevalence of hearing impairment in the very premature survivors and difficulties in compliance with a VROA based hearing screen. We see an advantage in directing resources towards an early screening test, such as TEOAE, that can be applied while the target population is still captive.