Figure 7.

Model predictions of the effect of the vestibular hole. (A) Simple model of the middle ear as a Norton equivalent circuit, providing volume velocity U_S to the parallel combination of the inner ear load (Z_C) and the impedance of the hole (Z_hole). The Norton equivalent is composed of an ideal volume-velocity source and the output impedance of the middle ear (Z_out). (B) Predictions of our simple model with a 180 μm diameter hole partially plugged by a pressure sensor (equivalent radius=53 μm) were at least qualitatively similar to the experimental changes we found in P_V and U_S [see text and Figs. 3C, 4B]: The changes in P_V were limited to low frequencies (solid and dashed-dotted lines); the changes in U_S were small (dashed and dotted lines).