Rodriguez Jorge J, Zenner H P, Hemmert W, Burkhardt C, Gummer A W
Sektion für Physiologische Akustik und Kommunikation, Hals-Nasen-Ohren-Klinik, Universität Tübingen.
HNO. 1997 Dec;45(12):997-1007. doi: 10.1007/s001060050185.
A complete battery of audiometric methods is required for the differential diagnosis of different hearing disabilities (including puretone audiometry, impedance, stapes reflex, speech audiometry, brainstam evoked response audiometry, otoacoustic emissions, etc.). In many cases, a comprehensive diagnosis is not possible. Here we describe a new technique based on a laser-Doppler vibrometer that has the potential for non-invasive diagnosis not only middle ear disease but also cochlear pathologies. Disturbance of cochlear function can be ascertained because the input impedance of the cochlea acts as a mechanical load on the middle ear and therefore influences motion of the umbo. In the present study vibration of the umbo and eardrum were measured with a commercially available laser-Doppler vibrometer coupled directly into a standard surgical microscope. The use of the microscope allowed non-invasive measurements of vibrations without having to introduce reflecting material onto the tympanic membrane. Sound pressure was measured with a calibrated probe microphone placed near the tympanic membrane. The displacement response and the specific acoustic impedance of the umbo were calculated from the velocity and sound pressure measured. For normal hearing subjects, the amplitude of the umbo's displacement for frequencies from 0.1 kHz to 1 kHz was 1 nm at 60 dB SPL and decreased with a slope of 6 dB/octave for frequencies between 1 and 5 kHz. A strong correlation was found between the specific acoustic impedance of the umbo and hearing thresholds for hearing-impaired subjects (having otosclerosis or sensorineural hearing losses). The frequency response of the umbo proved to be a means for evaluating the function of both the middle ear and the cochlea under pathological conditions. The measurement technique described is also suitable for intraoperative investigation of the frequency response of the opened middle ear, as well as for the in situ frequency response of partial and total ossicular replacement prostheses.
对于不同听力障碍的鉴别诊断（包括纯音听力测定、声阻抗、镫骨反射、言语测听、脑干诱发电位测听、耳声发射等），需要一套完整的听力测定方法。在许多情况下，无法进行全面诊断。在此，我们描述一种基于激光多普勒振动计的新技术，它不仅有可能对中耳疾病，而且对耳蜗病变进行非侵入性诊断。可以确定耳蜗功能的紊乱，因为耳蜗的输入阻抗作为中耳的机械负载，从而影响鼓膜脐的运动。在本研究中，使用直接耦合到标准手术显微镜中的市售激光多普勒振动计测量鼓膜脐和鼓膜的振动。显微镜的使用使得能够在无需在鼓膜上引入反射材料的情况下对振动进行非侵入性测量。用置于鼓膜附近的校准探针麦克风测量声压。根据测得的速度和声压计算鼓膜脐的位移响应和比声阻抗。对于听力正常的受试者，在60 dB SPL时，0.1 kHz至1 kHz频率下鼓膜脐的位移幅度为1 nm，在1至5 kHz频率之间以6 dB/倍频程的斜率下降。在听力受损受试者（患有耳硬化症或感音神经性听力损失）中，发现鼓膜脐的比声阻抗与听力阈值之间存在很强的相关性。事实证明，鼓膜脐的频率响应是评估病理条件下中耳和耳蜗功能的一种手段。所描述的测量技术也适用于对开放中耳的频率响应进行术中研究，以及对部分和全听骨置换假体的原位频率响应进行研究。
