ABSTRACT
Objective To study the effect of typical middle ear diseases on sound compensation of round window (RW) stimulation, so as to provide references for the optimal design of middle ear implants by RW stimulation. Methods The finite element model of the middle ear and cochlea was built by CT scanning and reverse engineering technique, and its reliability was also verified. On the basis of the model and by changing material properties of corresponding tissues, three typical middle ear diseases were simulated: hardening of stapedial annular ligaments, abnormal stapedial bone growth and hardening of anterior mallear ligaments. Then the response from displacement of basilar membrane (BM) was compared to analyze the impact of 3 types of middle ear diseases on sound compensation of RW stimulation. Results The stapes with abnormal bone growth severely deteriorated the equivalent sound pressure (ESP) of RW stimulation at higher frequencies, while the hardening of stapedial annular ligaments and the hardening of anterior malleus ligaments prominently decreased ESP of RW stimulation at lower frequencies. Among the 3 types of middle ear diseases, hardening of stapedial annular ligaments affected the sound compensation of RW stimulation more significantly with the amount of the ESP reduction up to 17 dB. Conclusions Middle ear diseases can deteriorate the sound compensation of RW stimulation seriously with large deterioration, Therefore, the output stimulation of the actuator should be targeted to improve the design of the middle ear implants by RW stimulation.
ABSTRACT
Objective To design an improvement plan of piezoelectric actuator with displacement magnification structure, so as to reduce power consumption of the existing incus-stimulating piezoelectric actuator for middle ear implant. Methods First, based on anatomical structure of human ear, the piezoelectric actuator with displacement magnification structure and the one just composed of piezoelectric stack were designed, respectively, and the corresponding coupled mechanical models of the middle ear and the piezoelectric actuator were established. By comparing the calculation results from the two types of coupling mechanical models, the hearing compensation property and power consumption of the actuator before and after the implantation of displacement magnification structure were analyzed. Results After adding the displacement magnification structure, the sound pressure level (SPL) at 1 kHz frequency was increased from 100 dB to 113 dB, when the piezoelectric actuator was stimulated by 10.5 V effective voltage. In addition, when the actuator was stimulated by the piezoelectric stack, its power consumption at the frequency of 1, 2 and 4 kHz were 6.42, 1.56 and 0.28 mW, respectviely; after introducing the displacement magnification structure, power consumption at the above-mentioned 3 frequencies decreased to 0.39, 0.09 and 0.01 mW, resepectively. Conclusions Piezoelectric actuator with displacement magnification structure in this study can improve hearing compensation ability of the incus-stimulating middle ear implant and effectively reducing the power consumption. The research findings will help to further improve the structure design of middle ear implant, thus achieving better hearing compensation effect.
ABSTRACT
Objective To improve the design plan and get a piezoelectric actuator with displacement magnification structure,so as to reduce power consumption of the existing incus-stimulating piezoelectric actuator for middle ear implant.Methods Based on anatomical structure of human ear,the piezoelectric actuator with displacement magnification structure,and the one only composed of piezoelectric stack were designed,respectively,then the corresponding coupled mechanical models of the middle ear with the piezoelectric actuator were established.By comparing the calculation results from the two types of coupled mechanical models,the hearing compensation property and power consumption of the actuator before and after the implantation with the displacement magnification structure were analyzed.Results After adding the displacement magnification structure,the sound pressure level (SPL) at 1 kHz frequency was increased from 100 dB to 113 dB when the piezoelectric actuator was stimulated by 10.5 V effective voltages.In addition,for the piezoelectric stack,its power consumption at the frequency of 1,2 and 4 kHz were 6.42,1.56 and 0.28 mW,respectively;after introducing the displacement magnification structure,the power consumption at the above-mentioned 3 frequencies decreased to 0.39,0.09 and 0.01 mW,respectively.Conclusions Piezoelectric actuator with displacement magnification structure in this study can improve hearing compensation ability of the incus-stimulating middle ear implant,and effectively reduce the power consumption.The research findings will help to further improve the structure design of middle ear implant,thus achieving better hearing compensation effect.
ABSTRACT
Objective To improve the design plan and get a piezoelectric actuator with displacement magnification structure,so as to reduce power consumption of the existing incus-stimulating piezoelectric actuator for middle ear implant.Methods Based on anatomical structure of human ear,the piezoelectric actuator with displacement magnification structure,and the one only composed of piezoelectric stack were designed,respectively,then the corresponding coupled mechanical models of the middle ear with the piezoelectric actuator were established.By comparing the calculation results from the two types of coupled mechanical models,the hearing compensation property and power consumption of the actuator before and after the implantation with the displacement magnification structure were analyzed.Results After adding the displacement magnification structure,the sound pressure level (SPL) at 1 kHz frequency was increased from 100 dB to 113 dB when the piezoelectric actuator was stimulated by 10.5 V effective voltages.In addition,for the piezoelectric stack,its power consumption at the frequency of 1,2 and 4 kHz were 6.42,1.56 and 0.28 mW,respectively;after introducing the displacement magnification structure,the power consumption at the above-mentioned 3 frequencies decreased to 0.39,0.09 and 0.01 mW,respectively.Conclusions Piezoelectric actuator with displacement magnification structure in this study can improve hearing compensation ability of the incus-stimulating middle ear implant,and effectively reduce the power consumption.The research findings will help to further improve the structure design of middle ear implant,thus achieving better hearing compensation effect.