早产儿最大长度序列脑干听觉诱发电位的波形特点及发育变化

Characteristic and development of maximum length sequence brainstem auditory evoked potential wave form in preterm infants

目的研究早产儿最大长度序列（maximum length sequence，MLS）脑干听觉诱发电位（brainstem auditory evoked potential，BAEP）的波形特点和发育规律及其与声刺激速率的相关关系。方法排除听力及脑损伤危险因素的相对正常早产儿89例，脑干听觉诱发电位检测时间为生后3～7d及纠正胎龄37～42周，对照组正常足月儿38例，检测时间为生后3～7d。声刺激速率为91、227、455次／s，观察指标为Ⅰ、Ⅲ、V波的潜伏期，Ⅰ-Ⅲ、Ⅲ-V、Ⅰ-V峰间期及Ⅰ、Ⅲ、V波振幅。结果早产儿MLS BAEP以Ⅰ、Ⅲ、V波分化发育较清晰，各波的潜伏期、峰间期和振幅都与声刺激速率相关。常规及MLS BAEP在各声刺激速率时，波形的潜伏期和峰间期都与胎龄呈正相关，与振幅呈负相关。声刺激速率为21次／s时，早产儿Ⅰ波、V波潜伏期分别为（2．43士0．23）ms和（7．36士0．27）ms较足月儿长；声刺激速率为91、227次／s时，早产儿组Ⅰ-Ⅲ峰间期相对足月儿组有所缩短而Ⅲ-V峰间期相对延长（P〈0．05），在455次／s时差异更加显著（P〈0．01）。结论MLS BAEP可以用于早产儿脑干听觉功能检测，91、227和455次／s是早产儿较适宜的声刺激速率。MLS BAEP通过提高声刺激速率，加大神经元负荷，有助于提高诊断价值。

Objective To study the character and development of maximum length sequence （MLS） brainstem auditory evoked potential （BAEP） wave form in preterm infants and the correlation between MLS BAEP and the click rate. Methods Preterm group included 89 preterm infants （gestational age 29 to 36＋3 weeks） without any perinatal complication and risk factors of brain and auditory injury. The recording of conventional and MLS BAEP was performed in 3 to 7 days after birth and in 37 to 42 weeks of postconceptional age. Normal term group included 38 healthy term babies, whose BAEP was recorded in 3 to 7 days after birth. MLS BAEP was recorded with the click rate at 91/s, 227/s, 455/s, and the conventional BAEP was recorded at 21/s as control. Latencies and amplitudes of wave I, Ⅲ and V and interpeak intervals of I-Ⅲ, Ⅲ-V and I-V were measured. Results Wave I, Ⅲ and V were more clear and identifiable than other waves in both conventional and MLS BAEP in preterm group. The latencies and interpeak intervals of all MLS BAEP components in preterm group were correlated positively with the click rate, while all wave amplitudes were correlated negatively. With the increase of gestational age, all wave latencies and interpeak intervals decreased while amplitudes increased at all click rates in preterm infants （P〈0. 05）. In 37 to 42 week of postconceptional age, no statistically significant differences were found between preterm group and term group in I-V interpeak interval. Comparing with normal term group, MLS BAEP I-Ⅲ interval decreased significantly at all 91/s and 227/s in preterm group（P〈0.05） whereas the Ⅲ-V interval increased significantly and particularly at 455/s （P〈0.01）. Conclusions MLS BAEP may be a better method to improve the diagnosis by increase the velocity of sound stimulation, which can be used to measure the brainstem auditory function in preterm infants, and 91/s, 227/s and 455/s are relatively proper click rates for preterm neonates.