Anomalous Screening Outcomes from Click-Evoked Otoacoustic Emissions and Auditory Brainstem Response Tests

Abstract

Transiently evoked otoacoustic emissions (TEOAE) and auditory brainstem response (ABR) tests were used in parallel to screen 862 neonates with risk factors for hearing loss. Seven neonates (0.81%) passed on TEOAE screen yet failed on ABR in one ear (six neonates) or both ears (one neonate). This combination of results has been termed 'anomalous'. Examination of audiometric results obtained on follow-up shows that in one ear of one neonate the result was consistent with the later confirmed audiogram shape. The explanation for the anomalous results in the remaining ears is unclear although neural maturation and the effects of hyperbilirubinaemia are possibilities. There were no instances of progressive or retrocochlear hearing loss identified. None of the seven neonates had better ear hearing loss of > or = 40 dB on long term follow-up.

The Mitochondrial Connection in Auditory Neuropathy

“…Deltenre et al [1997] reported cases of desynchronized ABRs, intact cochlear microphonics and click evoked OAEs in infants with hyperbilirubinemia needing exchange transfusion. According to Wood et al [1998], this pattern of results accounted for 0.81% (7/862) of those failing at least 1 ear. Interestingly, this percentage is similar to the 2.0% of healthy newborn infants that have bilirubin levels exceeding 20 mg/dl [Newman et al, 1999].…”