School of Mechatronic Engineering, China University of Mining and Technology, Xuzhou 221116, China.
State Key Laboratory of Mechanical System and Vibrations, Shanghai Jiaotong University, Shanghai 200240, China.
Sensors (Basel). 2017 Nov 2;17(11):2515. doi: 10.3390/s17112515.
Implantable middle ear hearing devices (IMEHDs) have been developed as a new technology to overcome the limitations of conventional hearing aids. The piezoelectric cantilever transducers currently used in the IMEHDs have the advantages of low power consumption and ease of fabrication, but generate less high-frequency output. To address this problem, we proposed and designed a new piezoelectric transducer based on a piezoelectric stack for the IMEHD. This new transducer, attached to the incus body with a coupling rod, stimulates the ossicular chain in response to the expansion-and-contraction of its piezoelectric stack. To test its feasibility for hearing loss compensation, a bench testing of the transducer prototype and a temporal bone experiment were conducted, respectively. Bench testing results showed that the new transducer did have a broad frequency bandwidth. Besides, the transducer was found to have a low total harmonic distortion (<0.75%) in all frequencies, and small release time (1 ms). The temporal bone experiment further proved that the transducer has the capability to produce sufficient vibrations to compensate for severe sensorineural hearing loss, especially at high frequencies. This property benefits the treatment of the most common sloping high-frequency sensorineural hearing loss. To produce a 100 dB SPL equivalent sound pressure at 1 kHz, its power consumption is 0.49 mW, which is low enough for the transducer to be utilized in the IMEHD.
可植入中耳听力设备 (IMEHD) 的开发是作为一种新技术来克服传统助听器的局限性。目前在 IMEHD 中使用的压电悬臂换能器具有功耗低和易于制造的优点，但产生的高频输出较少。为了解决这个问题，我们提出并设计了一种基于压电堆叠的用于 IMEHD 的新型压电换能器。这种新的换能器通过耦合杆连接到砧骨体上，响应其压电堆叠的伸缩来刺激听骨链。为了测试其用于听力损失补偿的可行性，分别对换能器原型进行了台架测试和颞骨实验。台架测试结果表明，新型换能器确实具有较宽的频率带宽。此外，在所有频率下，换能器的总谐波失真（<0.75%）都很低，释放时间（1ms）也很小。颞骨实验进一步证明了该换能器具有产生足够振动以补偿严重感音神经性听力损失的能力，尤其是在高频。这种特性有利于治疗最常见的高频陡降型感音神经性听力损失。为了在 1kHz 时产生 100dB SPL 的等效声压，其功耗为 0.49mW，足以使换能器在 IMEHD 中使用。
