小儿中度蜗后听觉神经损害的临床研究

Moderate retrocochlear auditory nerve impairment in children

目的探讨以听性脑干反应（ABR）中度异常、畸变产物耳声发射（DPOAE）正常为特征的中度蜗后听觉神经功能障碍小儿的临床与听力学特征。方法选取2003年1月至2007年12月小儿听力专科中ABR中度异常、刺激声强度（正常听力级）在70-80dB时才出现波Ⅴ分化，DPOAE正常，中耳功能分析排除中耳传导功能异常者为研究对象，列为蜗后病变研究组，共61例（80耳），年龄1^＋月至3岁，平均5．59个月。另选择ABR波Ⅴ阈值介于50～80dBnHL、DPOAE异常、排除中耳病变的听力障碍患儿57例（85耳），年龄3个月至6岁，平均28．02个月，作为蜗性病变对照组。从该院小儿听力中心资料库中，随机抽取同时具备正常ABR和DPOAE的与研究组同年龄段样本共55例（84耳），年龄1个月至3岁，平均5．56个月，作为健康对照组。蜗后病变研究组、蜗后病变研究组及正常听力组间进行DPOAE幅值及引出率的比较。结果（1）61例蜗后病变研究组患儿的既往病史中，18例（29．51％）曾有中重度新生儿期高胆红素血症史，12例（19．67％）有外周性脑积水既往病史；（2）19例（38耳）为双耳发病，42例（42耳）为单耳发病；（3）90dBnHL刺激声强度下，蜗后病变研究组61例80耳引出波Ⅰ的比例为87．50％（70／80），引出波Ⅲ的比例为96．25％（77／80），引出波Ⅴ的比例为100％（80／80）；（4）蜗后病变研究组与正常听力对照组在中高频点的DPOAE幅值和引出率差异无统计学意义；蜗后病变研究组与蜗性病变70、80dB对照组在中高频点的DPOAE幅值和引出率差异有统计学意义。结论在蜗后听觉障碍的临床病例中，存在中度蜗后听觉神经损害类型。

Objective To explore the clinic characteristics, audiological characteristics in children with moderate retrocochlear auditory nerve impairment characterized by moderate abnormal results of auditory brainstem response （ABR） and normal results of distortion product otoaeoustic emission （DPOAE）. Methods Between January 2003 and December 2007,sixty-one cases（80 ears） with moderate abnormal ABR（wave Ⅴ was differentiated at 70-80 dB nHL） but normal DPOAE were enrolled in the study as retrocochlear disease group. The mean patient age was 5.59-month-old, with a range of 1^＋ months to 3 years. The cases with abnormal conductive function were excluded. Fifty-seven cases （85 ears） with abnormal ABR （threshold of wave Ⅴ was 50-80 dB nHL ）and abnormal results of DPOAE without abnormal conductive function were selected as the cochlear lesion group,and the mean patient age was 28.02-month-old,with a range of 3 months to 6 years. Fifty-five same age children （84 ears） with normal ABR and normal DPOAE were subjected as normal control group randomizedly selected from the pediatric hearing center,and the mean age were 5. 56-month-old, with a range of 1 months to 3 years. The DPOAE amplification and rate of presentation was compared among the three groups. Results （1） 29.51 percent of cases （18 cases） had a history of moderate or severe hypercholesterolemia, 19.67 percent of cases （12 cases） had a history of peripheral hydrocephalus. （2） 19 cases （38 ears）had abnormality in both ear,while 42 cases （42 ears） in one ear. （3） Among the 80 ears,ABR to click stimuli presented at 90 dB nHL,wave Ⅰ was developed in 70 ears （87.50%） ,wave Ⅲ was developed in 77 ears（96.25%）,wave Ⅴ was developed in all the ears（100%）. （4）When compared to normal control group,the DPOAE amplification and presentation rate were the same at middle and high frequency; when compared to the cochlear lesion group which had ABR threshold of 70,80 dB nHL, the DPOAE amplification and presentation rate had significant difference. Conclusion Retrocochlear auditory nerve impairment has moderate degree impairment.