早产儿畸变产物耳声发射的特性分析

目的 :研究早产儿畸变产物耳声发射 (DPOAE)的幅值、信噪比、本底噪声等基本特性。方法 :应用DP2 0 0 0型耳声发射仪对 31例早产儿 (5 9耳 )和 19例足月新生儿 (35耳 )在出生后 3d～ 1周内行DPOAE检测。结果 :早产儿DPOAE反应幅值曲线有一峰点 (f2 =15 87Hz)和一谷点 (f2 =4 0 0 0Hz) ,早产儿各频率反应幅值均低于足月新生儿相应频率 (P <0 .0 5 ) ;早产儿DPOAE信噪比SNR于f2 =4 0 0 0Hz处最高 ,f2 =10 0 0Hz处最低 ,4 0 0 0Hz、3175Hz及 15 87Hz、12 6 0Hz、10 0 0Hz处SNR均低于足月儿相应水平 (P <0 .0 5 ) ;早产儿DPOAE本底噪声在低频段 (f2 =12 6 0Hz、10 0 0Hz)显著高于其他频率 ,4 0 0 0Hz处噪声水平最低 (P <0 .0 1) ,3175Hz、2 5 2 0Hz及 2 0 0 0Hz处早产儿组噪声水平均低于足月儿组 (P <0 .0 5 )。结论 :早产儿DPOAE反应幅值、信噪比及本底噪声与足月儿相比差异均有统计学意义。该差异与耳蜗外毛细胞发育过程相关 ,还可能与中耳及外耳的发育有关

Characteristic of distortion product otoacoustic emissions for preterm newborn

OBJECTIVE: To investigate the characteristic of distortion product otoacoustic emissions (DPOAE) amplitude, SNR and noise in preterm newborns. METHOD: DPAOEs at the 2f1-f2 frequency were recorded from 59 ears of 31 preterm newborns and 35 ears of 19 healthy fullterm newborns in response to equilevel primary tones at postnatal 3 days to 1 week. Detailed test included the recording of DPAOEs, SNR and noise. RESULT: The average DPOAE audiogram of preterm newborns illustrating the frequency response of these emissions demonstrated a maximum at 1,587 Hz and a minimum around 4,000 Hz. The DPOAE response amplitude of preterm newborn was lower than that of fullterm in every frequency(P < 0.05). The SNR was higher at 4,000 Hz than that at low frequency, but was lower at 1000 Hz than that at high frequency. At 4,000, 3,175, 1,587, 1,260 and 1,000 Hz, the SNR of preterm were lower thad fullterm(P < 0.05). The noise was higher at low frequency than that at high frequency. CONCLUSION: The characteristics of DPOAE in preterm newborn are different from fullterm newborn. These differences may indicate immaturity in cochlear function. Outer hair cell function are hypothesized sources of this immaturity, although some contribution from the immature middle ear and outer ear cannot be ruled out.