Distortion product otoacoustic emissions in term infants with a low Apgar score

Abstract

Conclusion. Term infants with a low Apgar score have cochlear impairment, mainly at the frequencies 1–3 kHz. Compared with infants with both a low Apgar score and hypoxic-ischaemic encephalopathy we reported before, the impairment is less severe. Objective. To detect any peripheral impairment of cochlear origin in infants with a low Apgar score. Subjects and methods. Fifty-four term infants with a low Apgar score at 1 and/or 5 min but without clinical signs of hypoxic-ischaemic encephalopathy were recruited. Distortion product otoacoustic emissions (DPOAEs) were recorded with the f₂ primary tone at 10 frequencies (0.5–10 kHz) on days 3–5 and 1 month after birth. Results. 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 (χ²=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%, χ²=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.

• Otoacoustic emissions
• cochlea
• neonatal hearing screening
• hearing impairment
• Apgar score