Department of Otolaryngology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA.
Otol Neurotol. 2012 Apr;33(3):425-31. doi: 10.1097/MAO.0b013e318245cecb.
Mechanical stimulation through a cochlear third window into the scala tympani in a chinchilla model with normal and fixed stapes can generate cochlear responses equivalent to acoustic stimuli.
Cochlear stimulation via the round window (RW) using active middle ear implants (AMEIs) can produce physiologic responses similar to acoustic stimulation including in a model of stapes fixation. However, pathologic conditions, such as advanced otosclerosis, can preclude delivery of sound energy to the cochlea through the oval window and/or the RW.
Cochlear microphonic (CM) and laser Doppler vibrometer measurements of stapes and RW velocities were performed in 6 ears of 4 chinchillas. Baseline measurements to acoustic sinusoidal stimuli (0.25-8 kHz) were made. Measurements were repeated with an AMEI driving the RW or a third window to the scala tympani before and after stapes fixation.
AMEI stimulation of the third window produced CM waveforms with morphologies similar to acoustic stimuli. CM thresholds with RW and third-window stimulation were frequency dependent but ranged from 0.25 to 10 and 0.5 to 40 mV, respectively. Stapes fixation, confirmed by laser Doppler vibrometer measurements, resulted in a significant frequency dependent impairment in CM thresholds up to 13 dB (at <3 kHz) for RW stimulation and a nonsignificant frequency-dependent improvement of up to 10 dB (at >3 kHz) via third-window stimulation.
AMEI mechanical stimulation through a third window into the scala tympani produces physiologic responses nearly identical to acoustic stimulation including in a model of stapes fixation with decreased efficiency.
在具有正常和固定镫骨的南美栗鼠模型中，通过耳蜗第三窗口进入鼓阶的机械刺激可以产生与声学刺激等效的耳蜗反应。
使用主动中耳植入物（AMEI）通过圆窗（RW）进行耳蜗刺激可以产生类似于声学刺激的生理反应，包括在镫骨固定模型中。然而，病理状况，如进展性耳硬化症，可以阻止声音能量通过卵圆窗和/或 RW 传递到耳蜗。
在 4 只南美栗鼠的 6 只耳朵中进行了耳蜗微音器（CM）和激光多普勒测振仪测量镫骨和 RW 速度。对声学正弦刺激（0.25-8 kHz）进行了基线测量。在固定镫骨之前和之后，使用驱动 RW 或第三窗口到鼓阶的 AMEI 重复进行测量。
AMEI 刺激第三窗口产生的 CM 波形形态与声学刺激相似。RW 和第三窗口刺激的 CM 阈值与频率有关，但范围分别为 0.25 至 10 mV 和 0.5 至 40 mV。通过激光多普勒测振仪测量证实的镫骨固定导致 RW 刺激的 CM 阈值在 0.25 至 3 kHz 范围内显著依赖于频率的降低，高达 13 dB，而通过第三窗口刺激，CM 阈值在 3 kHz 以上范围内的频率依赖性提高高达 10 dB。
AMEI 通过第三窗口进入鼓阶的机械刺激产生的生理反应几乎与声学刺激完全相同，包括在镫骨固定模型中，但其效率降低。
