High frequency immittance findings: newborn versus six-week-old infants.

This study aimed to compare the high frequency (1 kHz) tympanometry (HFT) and acoustic reflex (AR) measures obtained from infants at birth and at 6-7 weeks of age. HFT results and AR thresholds using a 2-kHz tone and broadband noise activators were obtained from 42 healthy full-term neonates (15 boys and 27 girls) at both test sessions, separated by six weeks. The results showed that the mean values of HFT test parameters and AR thresholds obtained at 6-7 weeks were generally greater than those obtained at birth. In particular, the differences in mean values of uncompensated admittance at 200 daPa, uncompensated peak admittance, uncompensated peak susceptance, peak-compensated static admittance, and AR thresholds with a 2 kHz tone and broadband noise were found to be statistically significant. The findings from this study suggest the need to have separate sets of normative HFT and AR data for infants at birth and 6-7 weeks.