Transient evoked otoacoustic emissions.

Objective: The purpose of this study was to collect parametric measures of TEOAEs in normal hearing children of various age-groups and to establish a normative baseline for Transient Evoked Otoacoustic Emissions (TEOAEs).

Methods: Sixty subjects were investigated in three age-groups: neonates, 0-1 month; infants, 1 month-1 year; and children, 1-6 years. Each group comprised of 20 subjects. All the subjects underwent medical examination by a pediatrician and an ENT surgeon. Screening for hearing was done by immittance testing, behavior observation and conditioned play audiometry. The TEOAEs were analyzed for the parameters of amplitude, cross-correlation (wave reproducibility) and signal-to-noise ratio (SNR).

Results: There was no difference between the mean amplitudes of the right and left ears in the groups. The females in the neonates group had higher emission amplitudes than the males. The mean amplitude of the subjects in the neonates group was significantly higher than the subjects in the infants or children groups. The cross correlation (wave reproducibility) was constant across the age. The mean SNR for all the subjects were well above 3 dB at frequencies 1.5 k, 2 k, 3 k and 4 kHz. The neonates group showed the lowest SNR ranging between 3.47 to 9.62 dB. The infants group showed the highest SNR ranging between 6.13 to 13.11 dB.

Conclusion: The TEOAEs response measures of SNR and cross correlation, at frequency bands 1.5, 2, 3 and 4 kHz, may provide more reliable outcomes than TEOAEs amplitude. Subjects in the age range of 0-1 month show lower SNRs than those in higher age ranges. The values can be used as normative data for screening and diagnostic purposes in the pediatric population.