Measurements of ossicular vibrations in the middle ear.

The vibrations of the ossicles were measured with a laser Doppler vibrometer in temporal bone specimens. The data contradicted the generally accepted view that the malleus and incus rotate about a fixed axis. The vibrations of the ossicles show a more complex pattern and, consequently, a more sophisticated model is needed to portray the behaviour of the middle ear in a satisfactory manner. But in turn models with many degrees of freedom make the identification process a very difficult task. This dilemma can be resolved if the system is divided into subsystems of less complexity where each subsystem can be studied in an appropriate manner. The excitation by electrostatic forces, as applied in this study, seems to be a powerful tool to make possible a study of parts of the ossicular chain.