Development of a cochlear input-impedacne measuring device and its application in the temporal bones of dogs

用一种新研制的陶瓷装置测量了犬的耳蜗输入阻抗。该装置由两个陶瓷双压片元件组成，一个用来激活踝骨，另一个用来拾取前者的振动，其形式为电输出，其大小随耳蜗阻抗的大小而变化。活体动物的平均阻抗在1 kHz、2 kHz和4 kHz时分别为13.9、20.6和37.8 mhm。圆窗的破裂导致了阻抗的降低，尽管影响的变化性很大。相反，通过放置牙科粘固剂关闭圆形窗口会导致一些动物的阻抗增加。

Cochlear input impedance was measured in dogs by use of a newly developed ceramic divice. The device was composed of two ceramic bimorph elements, one for activation of the stapes and the other for pick-up vibration of the former element in form of an electric output, which varies corresponding to the magnitude of the cochlear impedance. Average impedance in the resected tempral bones was 2.4 Mohm at 1kHz, 2.3 Mohm at 2 kHz and 6.3 Mohm at 4 kHz, while that in live animals was 13.9 Mohm at 1kHz, 20.6 Mohm at 2kHz and 37.8 Mohm at 4kHz. Rupture of the round window caused decrease in the impedance, though with great variability in the effects. In contrast, closure of the round window by placing a dental cement caused increase in the impedance in some animals.