Figure 10: Axial loading of the stapes. Loss of the middle ear transmission function in dB, related to the neutral position of the stapes (zero line) with increasing deflection in direction of the vestibulum. The graph displays the deflection in µm and the resulting factor of annular ligament stiffening (referring to the neutral position). In case of deflection of 67 µm, stiffening of the annular ligament by factor 15 resulted in this measurement with a transmission loss of 25 dB at 2 kHz. Already low pretensions of the annular ligament (for example by longer prostheses) lead to measurable transmission losses (measurements performed in fresh temporal bone specimens, stimulation with 50 mV (corresponding to 94 dB SPL) via the floating mass transducer on the stapes head).