Finite element modeling of a piezoelectric actuator coupled to the cochlear round window

Abstract Round window (RW) stimulation is an application of active middle ear implants. However, its clinical outcomes show a substantial degree of variability due to the mismatch of the diameter of the actuator and the RW membrane, and the surgically challenging for placing the actuator. To address this problem, we developed a new piezoelectric actuator for RW stimulation. Firstly, we specifically designed the actuator’s mechanical structure for the RW stimulation. Then, we constructed a finite element (FE) model of the piezoelectric actuator coupled with the human ear’s RW membrane. Using this coupled FE model, we studied the influence of the actuator’s supporting stiffness and the number of piezoelectric stack layers on the stimulated stapes velocity. Finally, we fabricated the piezoelectric actuator and tested its output on human cadaver temporal bones. The results show that the developed piezoelectric actuator has the advantages of a wide operating frequency range and controlled preload on the RW membrane.