Finite element analysis of the effects of a floating mass transducer on the performance of a middle ear implant.

Experimental evidence has shown that floating mass transducers (FMTs) play a key role in the performance of middle ear implants. However, because of the tiny size and complex structure of the middle ear, systematic experimental study of the influences of FMTs is difficult to carry out. In this paper we develop a FMT-attached middle-ear finite element model to investigate some effects of a FMT on the performance of a middle ear implant. This model was constructed based on a complete set of computerized tomography section images of a healthy volunteer's left ear. The validity of the developed model was verified by comparing the model-predicted motion of the tympanic membrane and stapes footplate with published experimental data. The result shows that the FMT produces a mass loading effect prominently at high frequencies, the force required to drive the incus to the equivalent of 100 dB sound pressure level (SPL) is about 89 microN, and setting the attachment position of the FMT close to the incudostapedial joint can enhance the driving effect.