The effect of the number of averaged responses on the measurement of transiently evoked otoacoustic emissions in newborns.

OBJECTIVE

The aim of this study was to examine the effect of the number of averaged responses on the measurement of transiently evoked otoacoustic emissions (TEOAEs).

METHODS

The study was performed on the background of a universal newborn hearing screening program implemented in Iaso Maternity Hospital. Two groups of full-term newborns with normal otoacoustic emissions were studied. The first group included 58 newborns (115) ears, in which 260 low-noise samples, provided by the default setting of the equipment used (ILO88), were presented. The second group included 58 newborns (113) ears, in which 20-50 averaged responses were presented, until the "pass" criteria would be met. Statistical comparison between the following parameters recorded during TEOAE measurement was performed: Overall response, signal-to-noise ratios, reproducibility (whole and partial), stimulus intensity, stimulus stability, input noise, noise rejection level and duration of testing.

RESULTS

Statistically significant differences were found in most of these parameters, except for overall response, stimulus intensity and noise rejection level.

CONCLUSIONS

Although a smaller number of clicks is usually sufficient to obtain a "pass" in newborn hearing screening programs, the quality of recording of TEOAEs is significantly improved by increasing the number of averaged low-noise responses.