Objective: This study aims to design a new electrode array which can be precisely located beneath the basilar membrane within the cochlear scala tympani. This placement of the electrode array is beneficial for increasing the effectiveness of the electrical stimulation of the auditory nerves and maximising the growth factors delivered into the cochlea for regenerating the progressively lost auditory neurons, thereby significantly improving performance of the cochlear implant systems.
Methods: The design process involved two steps. First, the biocompatible nitinol-based shape memory alloy, of which mechanical deformation can be controlled using electrical currents/fields activated by body temperature, was selected. Second, five different designs of the electrode array with embedded nitinol actuators were studied (Table 1). The finite element method was employed to predict final positions of these electrode arrays.
Results: The electrode array with three 6mm actuators at 2-8mm, 8-14mm and 14-20mm from the tip (Fig. 1) was found to be located most closely to the basilar membrane, compared with those in the other four cases.
Conclusions: A new nitinol cochlear implant electrode array with three embedded nitinol actuators has been designed. This electrode array is expected to be located beneath the basilar membrane for maximising the delivery of growth factors. Future research will involve the manufacturing of a prototype of this electrode array for use in insertion experiments and neurotrophin release tests.