Effects of inner ear pathology on the input impedance of the cochlea

利用激光多谱勒干涉仪或我们设计的压电陶瓷装置，研究了内耳病理对动物耳蜗输入阻抗的影响。在豚鼠中，测量了圆窗膜破裂、耳蜗膜破坏和内耳压力升高三种方法之一前后Umbo的振动幅度。圆窗膜的破裂导致Umbo振动在中频增加了10分贝。破坏耳蜗会使所有频率的振动增加10分贝。内耳压力负荷引起低频振动减小，中频振动增加。这表明，内耳阻抗的变化可以通过鼓膜的振动模式来检测。用压电仪测量了链状耳蜗阻抗。它是为将来在中耳手术中用于人类受试者而设计的。阻抗在1 kHz时为3.9兆欧姆，在较高频率时逐渐增大。

The effects of inner ear pathology on the input impedance of the cochlea were studied in animals using a laser-doppler interferometer or a piezoelectric ceramic device of our design. In guinea pigs, vibration amplitudes of the umbo were measured before and after either one of the following three procedures ; rupture of the round window membrane, destruction of the cochlea and increase in inner ear pressure. Rupture of the round window membrane caused increase in umbo vibration up to 10 dB in mid-frequencies. Destruction of the cochlea resulted in 10 dB increase in the vibration at all the frequencies. Pressure loading to the inner ear induced the decrease in the vibration at low frequencies and the increase at mid-frequencies. This suggested that the changes in the inner ear impedance can be detected by the vibration mode of the tympanic membrane.Chaine cochlear input impedance were measured uaing a piezoelectric device. It was designed for future use in human subjects during middle ear surgery. The impedance value was 3.9 Megohm at 1 kHz, which gradually increased at higher frequencies.