Influence of a Cochlea Implant Electrode on the Traveling Wave Propagation

The work presents the influence of a cochlea implant electrode on the traveling wave propagation using a passive cochlea box model simulating different lengths and positions of the electrode with respect to the basilar membrane. Since a possible residual hearing is shown to be beneficial for an implanted patient, it is of great interested how the traveling wave propagation on the basilar membrane is affected by the electrode carrier. Therefore an uncoiled 3D finite element model with the general dimensions of the human cochlea is implemented. The basilar membrane, following the morphological and bio-mechanical properties, is tapered and orthotropic. In addition to the 3D box model a cochlea implant electrode is included. The position of the electrode is shifted inside scala tympani to simulate different distances to the basilar membrane as well as the case of a partial contact. With this model it is possible to predict whether the use of special electro-acoustic stimulation electrodes is beneficial for patients due to their residual hearing range or if the use of standard electrodes is the better choice. The results show the effects of different electrode lengths as well as the consequence of deep electrode insertion.