小儿蜗后听觉神经损害并耳蜗受损的听力学特征分析

Audiological Characteristics of Cochlear and Retrocochlear Damages in Children

目的探讨听性脑干反应(auditory brainstemresponse,ABR)严重异常、畸变产物耳声发射(distor-tion product otoacoustic emission,DPOAE)轻微异常为特征的小儿蜗后听觉神经功能损害同时合并耳蜗功能受损的临床听力学特征。方法选取2002～2006年听力专科中ABR严重异常、最大强度声刺激(103dB nHL)时才出现波Ⅴ或无波分化、排除了中耳传导功能异常组,镫骨肌声反射消失、DPOAE轻微异常患儿30例(47耳)作为研究对象,详细登记围产期病史,并与同龄听力正常对照组、蜗性病变听力损害组比较DPOAE幅值及引出率的异同。结果①30例蜗后病变合并耳蜗功能轻度受损的患儿中,23例(76.67%)新生儿期有高胆红素血症病史,其中13例(56.52%)血中间接胆红素水平达重度标准,曾经"换血"治疗和/或遗留核黄胆所致脑性瘫痪;②蜗后病变合并耳蜗功能轻度受损耳,DPOAE幅值较正常对照组出现一定程度的下降,而与ABR波V阈值为60dB nHL的蜗性病变耳DPOAE幅值相近;③蜗后病变合并耳蜗功能轻度受损耳DPOAE幅值异常的频率点分布主要在F9、F10和F11三个频点。结论以蜗后病变为主的听力损害患儿中,存在一定比例的耳蜗同时受累现象,受累的部位主要在耳蜗的基底部,以高频听力损失为主;新生儿期重度高胆红素血症是导致这一现象的最主要致病因素。

Objective The purpose of this study was to explore the audiological characteristics of the cochlear and retrocochlear damages in children. The major clinical manifestations of the hearing loss are severely abnormal ABR findings accompanied with slightly abnormal DPOAE results. Methods Between 2002 and 2006, 30 cases （ 47 ears） with severely abnormal ABR（only wave ） was differentiated or no response to click stimuli presented at 103 dB nHL） and slightly abnormal results of DPOAE were enrolled in the study. The subjects were free of any abnormal conductive functions and the stapedial reflexes were absent. Histories in perinatal period were recorded in detail. The responses of DPOAE were compared among the study goup,cochlear lesion group and normal control group. Results （1）76.67 percent of cases in the study group had a history of hypercholesterolemia during neonatal period, 56.52 percent underwent exchange transfusion and/or had cerebral palsy induced by kernicterus and the level of hemobilirubin was high. （2）The DPOAE amplitudes in the study group were slightly lower than that in the normal control group and almost the same as in cochlear lesion group（ the threshold of ABR wave V was 60 dB nHL）. （3）The abnormal amplitudes of DPOAE in the study group were mainly noted in F9, F10 and Fll. Conclusion The chil- dren with retrocochlear auditory nerve impairment often have cochlear impairment at the same time. The main site of lesion is in basilar part of cochlea and the hearing loss was more prominent at high frequencies. Hypercholesterolemia of newborns is the most common cause of this impairment.