Purpose
: To compare preterm and term neonates in relation to the presence and amplitude of Distortion Product Otoacoustic Emissions (DPOAEs), as well as to characterize them regarding risk indicators for hearing loss.
Methods
: Study realized by the analysis of the DPOAEs (frequencies of 2000, 3000, 4000, 6000 and 8000 Hz) and risk indicators for hearing loss. The neonates were grouped according to the gestational age. The results were analyzed by ANOVA, Kruskal-Wallis and Chi-square tests (5%).
Results
: The sample consisted of 109 neonates (218 ears) in homogenous distribution related to gender and preterm/term classification. A high risk for hearing loss was observed in 40.4% of the infants. From the risk indicators for hearing loss, the most common were the duration of the stay in incubators and intensive care units (ICU) longer than five days. The DPOAEs were present in 209 ears (95.9%). The absence of responses to DPOEAs was significantly more frequent in groups with lower gestational age. It was observed an increase of the amplitudes of the DPOEAs with the increase of the gestational age, except for the frequency of 8000 Hz in the left ear. There were no differences between ears and genders regarding the presence and amplitude of the DPOAEs.
Conclusion
: There are differences between preterm and term groups in relation to the presence and amplitude of the DPOAEs: higher probability of failure in the groups with lower gestational age and (nonlinear) increase of the amplitudes with the increase of the gestational age. The findings suggest the phenomenon of maturation of the peripheral auditory system.
Hearing; Neonatal screening; Infant, premature; Hair cells, auditory; Hearing disorders; Early diagnosis; Diagnostic techniques, otological; Speech, language and hearing sciences
