Characterization of spontaneous otoacoustic emissions in full-term newborns.

OBJECTIVE:To analyze the characteristics of spontaneous otoacoustic emissions (SOAEs) in full-term newborns. METHODS:A total of 236 ears from 147 randomly selected full-term Chinese neonates (82 females and 65 males), who had passed the initial newborn hearing screening, were assessed for SOAEs using the Capella OAE equipment (Madsen, Denmark). The test was performed in a sound booth. RESULTS:(1) The overall prevalence of SOAE was 56.77% of the ears. The prevalence of SOAEs was significantly higher in females (69.23%) than in males (41.51%, p<0.01), as well as in the right ears (64.17%) than in the left ears (49.14%, p<0.05). (2) The overall mean level of SOAE was 11.78±8.36dB SPL, with no significant differences between males (11.73±8.25dB SPL) and females (11.81±8.43dB SPL) or between the left (11.97±8.56dB SPL) and the right ears (11.65±8.22dB SPL). (3) The 25th and 75th percentiles of SOAE frequencies were 2.31 and 4.36kHz in females and 1.93 and 3.94kHz in males, which were statistically significantly different (p<0.01). In contrast, the SOAE frequency was not significantly different between ears (2.22-4.18kHz in the left ears and 2.17-4.14kHz in right ears). (4) The overall mean number of SOAEs was 3.70±2.75, with no significant differences in females (3.62±2.70) and males (3.86±2.87) or in right (3.70±2.55) and left ears (3.70±3.02). CONCLUSIONS:The prevalence rate of SOAE is significantly higher in females than in males and in the right ears than in the left ears in Chinese newborns. The frequencies of the SOAEs in newborns appeared to be higher than those reported in normal-hearing adults in the literature.