Distortion product otoacoustic emissions (DPOAEs) were analyzed at 6 months of age in term infants who had perinatal hypoxia-ischaemia (HI) and those who had a low Agar score alone to detect any abnormalities in cochlear function and any difference between the two groups of infants. The f2 primary tone was presented at ten frequencies (0.5-10 kHz). Both the left and right ears were tested. Compared to normal term controls, both the infants after perinatal HI and those with a low Apgar score alone showed lower DPOAE pass rates, mainly at 1-4 kHz at which the pass rates were decreased significantly (P < 0.05-0.01). The general pattern of DPOAE pass rates at different frequencies was similar in the two groups of infants. The pass rates at 1, 5 and 6 kHz tended to be lower in the infants after perinatal HI than those with a low Apgar score alone, although not statistically significant. Conclusions At 6 months of age, infants after perinatal HI or with a low Apgar score alone had a relatively poor cochlear function, mainly at 1-4 kHz. There are no major differences between the two groups of infants.

On days 3-5 DPOAE pass rates at most frequencies tended to be decreased, and were significant lower than those in normal term controls at 1, 2, 3, 5, 6 and 10 kHz (chi2=4.49-40.31, p<0.05-0.005). The greatest difference occurred at 1 kHz; 18.5% failed the DPOAE test and this was significantly higher than in the controls (4.3%, chi2=7.65, p<0.01). At 1 month the DPOAE pass rate at most frequencies did not show any significant improvement. The overall failure rate (14.8%) did not differ significantly from that on days 3-5.

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