[Comparison of transient evoked otoacoustic emissions in newborns and adults with frequency specific approach]

To investigate the difference of transient evoked otoacoustic emissions (TEOAE) between neonates and adults with the frequency-specific approach.

TEOAE were recorded from 112 newborns (62 females, 58 males) who passed hearing screening, and 32 adults (17 females, 15 males) tested with pure-tone threshold equal or less than 20 dBHL. Band reproducibility, signal-to-noise rate (SNR) of frequency-band and half-octave frequency analysis of TEOAE amplitude was recorded respectively.

Significant differences were found in two groups, the higher entire TEOAE level found in newborn [(15.18 +/- 4.39) dB SPL] was higher than that of adults group [(9.51 +/- 4.12) dB SPL, P < 0.05]. The lowest wave reproducibility and SNR were in first frequency band (0.8 kHz) for neonate, and then, in last frequency band (4.0 kHz) were for young adults. For newborns, the highest band reproducibility and SNR were presented at fourth frequency band (3.2 kHz). However, for adults, the highest band reproducibility and SNR were presented at second frequency band (1.5 kHz). Frequency space of the SNR response peaks between neonates and adults was 1.7 kHz. The level difference was 7.09 dB SPL. Half octave frequency analysis shows a TEOAE response peaks in neonates was (10.50 +/- 5.09) dB SPL at the 2828 Hz, and in adults, it was (2.84 +/- 5.33) dB SPL at the 1414 Hz. Frequency space of the TEOAE response peaks between neonates and adults was 1414 Hz. Level differences of TEOAE response peaks was 7.66 dB SPL. TEOAE response peak in adult appear at 1.5 kHz, and then dropped down correlated to increase of frequency. From the first to the last testing frequency band, the difference of TEOAE level between neonate and adult was found to increase correlated to increase of frequency.

TEOAE response level in newborn is higher than that in adult group. Further, the decrease of TEOAE response level presented more sharpens with the frequency increasing in adult. The frequency of TEOAE response peak in neonate (3.2 kHz) is higher than adult (1.5 kHz). The level of TEOAE response peak is also greater than adult.