[Distortion product otoacoustic emissions in infants from birth to two months].

BACKGROUND There is a need to determine parameters for the analyses of the distortion product otoacoustic emissions (DPOAE) of infants so that it can be used as a clinical criterion in auditory assessment. AIM To describe the DPOAE records of infants from birth to two months, considering the response level, noise level and the signal to noise ratio in all frequencies; the analysis of response level according to the variables of gender, timpanometry pressure peak, state of infant during the test and distribution of the response percentile level. METHOD 138 infants were evaluated, all of which presented no risk indicators for hearing loss and passed the hearing screening test. The parameters used were: L1=65 dB SPL and L2=50 dB SPL in the equipment ILO292-Otodynamics. RESULTS 70 male and 68 female were evaluated, with ages between 6 to 65 days. The medians for DPOAE level for each frequency (f2) varied between 6.0 dB SPL and 16.3 dB SPL. The medians for the noise level for each frequency (f2) varied between -12.5 dB SPL and -2.1 dB SPL. The medians for the signal to noise ratio for each frequency (f2) varied between 10.5 dB SPL and 25.5 dB SPL. CONCLUSIONS There was no statistically significant difference between genders and between ears for the response level. The timpanometry pression peak determined by three groups (between -50 and +50 daPa; <-50 daPa and >+50 daPa) indicated no influence on records of the response level. For clinical interpretation, percentile 5 can suggest hearing loss and percentile 95 can suggest normal hearing. Studies with infants who present hearing loss are considered important in order to complement the clinical criterion in case of presence of DPOAE and hearing loss.