Studies on the mechanics of the normal human middle ear.

The middle ear was studied in temporal bone preparations using a laser-Doppler interferometer. For measurements at a sound level of 80 dB SPL this method proved to be very reliable, as was shown by good reproducibility of results in experiments over more than 6 hours. The vibrations of the tympanic membrane and stapes footplate were studied from 200 Hz to 10 KHz and the results demonstrate a piston-like movement of the stapes footplate up to 120 dB SPL. The damping effect of the normal ear is located mainly at the footplate/cochlea level and the middle ear cavity per se does not contribute significantly to the stiffness of the middle ear system.