短潜伏期负反应诊断前庭水管扩大的意义

Significance of ASNR in the Diagnosis of Enlarged Vestibular Aqueduct

目的分析听性脑干反应（auditory brainstem response, ABR）测试时出现声诱发短潜伏期负反应（acous. tically evoked short latency negative response, ASNR）在诊断前庭水管扩大（enlarged vestibular aqueduct, EVA）的临床意义。方法对2003年5月-2005年6月收集的141例听力障碍患者的听性脑干反应检测结果进行分析，研究对象分为两组，EVA组为70例（140耳）经CT或MRI确诊的患者；对照组为71例（142耳）平均听阈〉60dBIIL的感音神经性聋、CT扫描无EVA的患者。听力学检查项目包括听性脑干反应、多频稳态反应测试、游戏测听或纯音测听、声导抗测试等。所有的患者均行颞骨CT扫描或耳蜗水呈像核磁共振检查了解耳蜗及内淋巴囊的发育情况。结果EVA组140耳（70例）ABR测试结果发现106耳（62例）记录到ASNR，占75．71％。在这106耳中，中度听力下降的17耳、重度听力下降的63耳、极重度听力下降的26耳中均引出负相波，ASNR的潜伏期在3．26±0．57ins处。所有记录到负相波的EVA患者，均发现其ABR的波I消失或不易识别，而波V的引出情况则各有不同。对照组71例（142耳）均未记录到ASNR。结论ASNR负相波的出现提示前庭水管扩大。

Objective To analyse and define the clinical audiological significance in finding the emerging of acoustically evoked short latency negative response （ASNR） during the auditory brainstem response （ABR） testing for the diagnosis of enlarged vestibular aqueduct （EVA）. Mothods The ABR waves analysis was performed on 141 patients with hearing loss cases collected from May,2003 to June, 2005.The patients were divided into two groups,①EVA group,70 cases （140 ears） diagnosed by CT scanning or magnetic resonance imaging （MRI） and ②controls 71 cases （141 ears） diagnosed as senserineural hearing loss （threshold 〉 60 dB HL） with no signs of EVA through CT scanning. The audiological testing included auditory brainstem response（ABR）, auditory steady- state responses（ASSR）, play audiometry or pure tone audiometry as well as tympanometry. All patients had CT or MRI examination for understanding the development of cochlear and endlymphatic sac. Results 106 ears （62 cases） of the 140 ears recorded the ASNR in ABR testing, the prevalence was 75.71% in EVA group.Among the 106 ears, ASNR was found in 17 ears with moderate hearing loss , 63 ears with severe and 26 ears with profound hearing loss. The latency of ASNR appeared at 3.26 ± 0.57 ms in the EVA patients＇ ABR testing. All of the EVA patients with ASNR recording had an significant feattrre in which the wave I disappeared or was difficult to discriminate, however, the derivation of wave V was quite different. All of the controls （71 cases） did not record the ASNR.Conclusion The occurrence of ASNR may indicate the diagnoses of enlarged vestibular aqueduct.