Analysis of the passive damped oscillation of the guinea pig stapes.

OBJECTIVE

To investigate the characteristic physical properties of the oscillating system in the intact middle ear using a high-speed camera.

DESIGN

We analysed the oscillation of the guinea pig stapes using a high-speed camera. The specimens were prepared so that the middle-ear structures were intact. Tones of various frequencies were delivered into the external auditory canal.

RESULTS

We found that the stapes showed a damped oscillation after the sound stimulation had stopped. The damped oscillation after the sound stimulation showed a specimen-specific frequency that was independent of the frequency of the stimulating sound. An injury to the bony labyrinth, which removed most of the mass from the oscillating system, attenuated the damped oscillation. Therefore, this damped oscillation is likely a passive motion, rather than a reverberation of the stimulating sound.

CONCLUSION

Analysing the passive damped oscillation may reveal the characteristic physical properties of the oscillating system in the near-intact middle ear. Further refinement of this simple and straightforward system may enhance basic and clinical research on the middle ear in a more intuitive way.