■对于中耳声音传递的实验研究,在没有内耳的情况下执行测量可能是有利的。在这种情况下,重要的是要知道内耳阻抗对中耳传递函数(METF)的影响。先前的研究在这方面提供了矛盾的结果。根据目前的研究,我们更详细地研究了内耳阻抗的影响,并找到了以前研究中偏差的可能原因。
■在我们的研究中制备了11个新鲜的冰冻颞骨。与内耳阻抗有关的因素,包括圆窗膜刚度,耳蜗造口术,实验设计涉及耳蜗液和耳蜗破坏。在完整样本中测量后作为参考(步骤1),圆窗膜被刺穿(步骤2),然后完全删除(步骤3)。在将耳蜗流体小心地抽吸通过鼓室(步骤5)和前庭骨(步骤6)之前,进行耳蜗造口术(步骤4)。最后,耳蜗被钻孔破坏(步骤7)。在每个步骤中测量并计算the骨踏板的平移和旋转运动。比较步骤的结果以量化与耳蜗引流过程相关的内耳阻抗变化的影响。
■随着内耳阻抗从步骤1降低到步骤7,每个频率下的METF曲线的幅度总体上逐渐增加。从第六步开始,在高于3kHz的高频下,测量的METF相对于完整组显著不同。这些差异是频率相关的。然而,从步骤5开始,旋转运动的显着减少出现在4.5kHz以上的频率处。
■这项研究证实了内耳阻抗仅在较高频率(≥3kHz)时对METF的影响。旋转运动在较高频率下对流体的排出更敏感。研究结果发现,没有影响耳蜗阻抗可能是由于不完全引流的耳蜗。
UNASSIGNED: For experimental studies on sound transfer in the middle ear, it may be advantageous to perform the measurements without the inner ear. In this case, it is important to know the influence of inner ear impedance on the middle ear transfer function (METF). Previous studies provide contradictory results in this regard. With the current study, we investigate the influence of inner ear impedance in more detail and find possible reasons for deviations in the previous studies.
UNASSIGNED: 11 fresh frozen temporal bones were prepared in our study. The factors related to inner ear impedance, including round window membrane stiffness,
cochleostomy, cochlea fluid and cochlea destruction were involved in the experimental design. After measuring in the intact specimen as a reference (step 1), the round window membrane was punctured (step 2), then completely removed (step 3). The
cochleostomy was performed (step 4) before the cochlear fluid was carefully suctioned through scala tympani (step 5) and scala vestibuli (step 6). Finally, cochlea was destroyed by drilling (step 7). Translational and rotational movement of the stapes footplate were measured and calculated at each step. The results of the steps were compared to quantify the effect of inner ear impedance changing related to the process of cochlear drainage.
UNASSIGNED: As the inner ear impedance decreases from step 1 to 7, the amplitudes of the METF curves at each frequency gradually increase in general. From step 6 on, the measured METF are significantly different with respect to the intact group at high frequencies above 3 kHz. The differences are frequency dependent. However, the significant decrement of rotational motion appears at the frequencies above 4.5 kHz from the step 5.
UNASSIGNED: This study confirms the influence of inner ear impedance on METF only at higher frequencies (≥3 kHz). The rotational motions are more sensitive to the drainage of fluid at the higher frequency. Study results that found no influence of cochlea impedance may be due to incomplete drainage of the cochlea.