Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts 02114, USA.
Ear Hear. 2012 Jan-Feb;33(1):35-43. doi: 10.1097/AUD.0b013e31822ccba0.
The goal of the present study was to investigate the clinical utility of measurements of ear-canal reflectance (ECR) in a population of patients with conductive hearing loss in the presence of an intact, healthy tympanic membrane and an aerated middle ear. We also sought to compare the diagnostic accuracy of umbo velocity (VU) measurements and measurements of ECR in the same group of patients.
This prospective study comprised 31 adult patients with conductive hearing loss, of which 14 had surgically confirmed stapes fixation due to otosclerosis, 6 had surgically confirmed ossicular discontinuity, and 11 had computed tomography and vestibular evoked myogenic potential confirmed superior semicircular canal dehiscence (SCD). Measurements on all 31 ears included pure-tone audiometry for 0.25 to 8 kHz, ECR for 0.2 to 6 kHz using the Mimosa Acoustics HearID system, and VU for 0.3 to 6 kHz using the HLV-1000 laser Doppler vibrometer (Polytec Inc, Waldbronn, Germany). We analyzed power reflectance |ECR| as well as the absorbance level = 10 × log10(1 - |ECR|). All measurements were made before any surgical intervention. The VU and ECR data were plotted against normative data obtained in a companion study of 58 strictly defined normal ears ().
Small increases in |ECR| at low-to-mid frequencies (400-1000 Hz) were observed in cases with stapes fixation, while narrowband decreases were seen for both SCD and ossicular discontinuity. The SCD and ossicular discontinuity differed in that the SCD had smaller decreases at mid-frequency (∼1000 Hz), whereas ossicular discontinuity had larger decreases at lower frequencies (500-800 Hz). SCD tended to have less air-bone gap at high frequencies (1-4 kHz) compared with stapes fixation and ossicular discontinuity. The |ECR| measurements, in conjunction with audiometry, could successfully separate 28 of the 31 cases into the three pathologies. By comparison, VU measurements, in conjunction with audiometry, could successfully separate various pathologies in 29 of 31 cases.
The combination of |ECR| with audiometry showed clinical utility in the differential diagnosis of conductive hearing loss in the presence of an intact tympanic membrane and an aerated middle ear and seems to be of similar sensitivity and specificity to measurements of VU plus audiometry. Additional research is needed to expand upon these promising preliminary results.
本研究旨在探讨在鼓膜完整、中耳充气的情况下，对传导性听力损失患者进行耳道反射率（ECR）测量的临床应用价值。我们还试图比较同一组患者中鼓室声导抗（UMB）速度（VU）测量和 ECR 测量的诊断准确性。
这项前瞻性研究共纳入 31 例传导性听力损失成年患者，其中 14 例因耳硬化症而手术证实镫骨固定，6 例手术证实听骨链中断，11 例经 CT 和前庭诱发肌源性电位检查证实为上半规管裂（SCD）。对所有 31 只耳朵进行了纯音测听（0.25 至 8 kHz）、使用 Mimosa Acoustics HearID 系统进行 0.2 至 6 kHz 的 ECR 测量以及使用 HLV-1000 激光多普勒测振仪（德国 Polytec 公司）进行 0.3 至 6 kHz 的 VU 测量。我们分析了功率反射率 |ECR| 以及吸收率水平=10×log10(1-|ECR|)。所有测量均在任何手术干预之前进行。将 VU 和 ECR 数据与在一项 58 例严格定义的正常耳的对照研究中获得的正常数据进行了比较（）。
在镫骨固定病例中，低频至中频（400-1000 Hz）的 |ECR| 略有增加，而 SCD 和听骨链中断则呈现窄带下降。SCD 和听骨链中断的区别在于，SCD 在中频（~1000 Hz）的下降幅度较小，而听骨链中断在低频（500-800 Hz）的下降幅度较大。与镫骨固定和听骨链中断相比，SCD 在高频（1-4 kHz）的气骨导差较小。结合纯音测听，|ECR| 测量可以成功地将 31 例中的 28 例分为三种病变。相比之下，结合纯音测听，VU 测量可以成功地将 31 例中的 29 例分为不同的病变。
在鼓膜完整、中耳充气的情况下，结合纯音测听，ECR 测量对传导性听力损失的鉴别诊断具有临床应用价值，其敏感性和特异性似乎与 VU 测量加纯音测听相当。需要进一步的研究来扩展这些有希望的初步结果。
