听力学表型在大前庭水管综合征早期诊断中的意义

Significance of audiological phenotypes to early diagnosis of large vestibular aqueduct syndrome

目的探讨大前庭水管综合征(LVAS)患者的听力学表型特点以期对LVAS早期诊断作出进一步指导。方法回顾分析63例大前庭水管综合征(LVAS)及8例疑似LVAS患者的病史、听力学及基因学检测结果。结果 LVAS患者中听性脑干反应(ABR)检查者58例,出现特征性的声诱发短潜伏期负反应(ASNR)29例,占总数的50.00%(29/58),负波潜伏期范围在2.56±0.39ms;58例非LVAS的听障患儿作为对照组,其均未发现ASNR;LVAS患者行纯音测听检查者22例(44耳),出现混合性听力下降者10例(20耳),占45.45%(20/44),其中有11耳在低频发现骨气导差,有12耳鼓室压图均为A型,2耳鼓室压图为As型,其中有8耳引出声反射;LVAS患者行SLC26A4基因筛查者26例,纯合突变11例,单杂合突变13例,阴性2例,阳性率92.31%(24/26)。结论大前庭水管综合征具有特征性表现ABR负波和中耳功能正常情况下出现骨气导差,该特征性表现对指导首诊患者进一步明确诊断,预防听力下降有重要意义。

Objective To report audiologic phenotype characteristics of patients with large vestibular aqueduct syndrome （LVAS） and their significance in early diagnosis. Methods The history, audiology and genetic test results of 63 patients with LVAS were reviewed. Fifty eight non-LVAS hearing impaired children served as the control, Results In 58 cas es undergoing auditory brainstem response （ABR） testing, 29 （50%） showed acoustically evoked short latency negative responses （ASNR） with an average latency of 2.56±0.39 ms. ASNRs were not found in the control group. Pure tone audiometry was performed in 22 cases （44 ears） and showed mixed hearing loss in 10 cases （20 ears, 45.45%）, and air-bone gap in low frequency in 11 ears. Tympanogram was type A in 12 ears （including As in 2 ears）, of which 8 produced acoustic reflex. Twenty six cases underwent SLC26A4 gene screening, which showed homozygous mutation in 11 cases, single heterozygous mutation in 13 cases and no mutation in 2 cases, yielding a total positive rate of 92.31% （24/26）. Conclusion Large vestibular conduct syndrome has a characteristic audiologic presentation that includes ABR negative waves, air-bone gaps at low frequencies and normal tympanograms. These characteristics are important in the diagnosis of hearing loss at first presentation as well as its management.