听神经病患者的临床听力学特点

Audiological characteristics of patients with auditory neuropathy

目的探讨听神经病患者的临床听力学特点。方法自2003年1月～2007年5月共收集到22例听神经病患者的病例。总结听神经病患者的病史、纯音测听、鼓室曲线图、镫骨肌声反射、言语测听、听性脑干反应(auditorybrainstemresponse,ABR)、耳蜗电图(electrocochleogram,ECochG)、畸变产物耳声发射(distortionproductotoacousticemission,DPOAE)及对侧白噪声抑制试验特点。其中10例患者行颅脑核磁共振成像(magneticresonanceimaging,MRI)检查。结果男性患者9例,女性患者13例,发病年龄为10～20岁,表现为进行性双耳听力下降,7例患者伴有耳鸣,最突出的表现是言语识别率差,无噪声接触史和耳毒性药物应用史,无家族史。22例患者听力曲线包括上升型13例,平坦型7例,高频听力下降型2例;鼓室曲线图均为A型;镫骨肌声反射均消失。所有听神经病患者ABR不能引出;全部病例均可记录到DPOAE,但不能被对侧白噪声抑制。耳蜗电图显示17例患者-SP/AP>0.4,5例患者动作电位(actionpotential,AP)消失或振幅很小,颅脑MRI检查无异常发现。结论听神经病患者听力学检查有以下共同特点:①双耳进行性听力下降,青少年发病,言语辨别能力甚差,听力损失程度不同,多为轻度到重度,少数为极重度,纯音听力大多为低频下降为主的感音神经性聋,一部分表现为平坦型、甚至高频下降型;②声导抗为"A"型鼓室曲线,镫骨肌声反射引不出;③DPOAE均可引出,耳声发射对侧抑制消失;④ABR引不出或严重异常;⑤影像学检查无任何阳性发现。听神经病的确定目前仍停留于功能性诊断,尚不能确定其病因、病变部位,详尽的听力学检查、典型的听力学表现有助于临床诊断。

Objective To explore the audiological characteristics of the auditory neuropathy.Methods Pure tone audiometry, acoustic stapedial reflex, speech audiometry, auditory brainstem response（ABR）, electrocochleogram（ECochO） as well as distortion product otoacoustic emission（DPOAE） and the contralateral suppression of white noise were administered to 22 patients with auditory neuropathy. Ten patients were investigated with brain magnetic resonance imaging（MRl）. Results Out of 22 cases, 13 female and 9 male complainted of bilateral hearing loss. The onset of the disorder was from 10 to 20 years old. Seven patients had a tinnitus of both ears. The pure tone audiogram showed mild or moderate sensorineural hearing loss. Stapedial reflex was absent in 22 patients. ABR was absent or severely abnormal in 22 cases. All of the patients had responses through DPOAE test and no suppression was achieved by contralateral white noise. ECochG demonstrated -SP/AP〉0.4 in 17 cases, and 5 patients＇ action potential（AP） amplitude was very low. The findings of MRI were normal. Conclusion Patients with auditory neuropathy were predominantly young at age. Pure tone audiometry showed mainly bilateral mild to moderate hearing loss at low frequencies, but their stapedial reflexes and ABR were absent. DPOAE was normal. The precise pathologic site of the disease is yet to be defined. The clinical auditory characteristics of auditory neuropathy are very important for diagnosing this disorder.