Neonatal hearing screening in a neonatal intensive care unit using distortion-product otoacoustic emissions

To determine pass and refer rates, and identify risk factors relating to refer responses, in neonates screened using distortion-product otoacoustic emissions (DPOAEs).

A total of 435 neonates admitted to the neonatal intensive care unit (NICU) of the Philippine General Hospital between May and October 2000 were screened using DPOAEs within 48 h of admission.

The male:female ratio in the sample was 1.05. In total, 56% of neonates were born preterm, the mean birthweight was 2,428.39 +/- 710.39 g and 8.9% weighed < 1,500 g. In total, 47.9% were delivered by Caesarian section and 44.9% were delivered vaginally. Almost 14% of neonates had 1-min Apgar scores of < 6, and 4% had 5-min Apgar scores of < 7. Approximately 95% of neonates had a poor perinatal history. Using pediatric aging it was noted that 46% of these neonates were born preterm. and 30.4% were small for gestational age. At least one neonatal disease was found in 42% of neonates, whilst 95.7% had to be given medication. The bilateral refer rate was 29.1%. Two-by-two analysis of risk factors for hearing loss and DPOAE measurements showed that only male sex seemed to have a significant association with a refer response. Neonates weighing < 1,500 g at birth showed a marginally significant association with a refer response (p = 0.07). All other neonates showed no crude association with DPOAE measurements.

These preliminary data show that a high proportion of NICU patients may have poor outer hair cell function, and thus poor hearing. In order to develop an effective neonatal hearing screening program, further studies of prevalence and risk factors should be pursued in the same setting.