细菌生物膜厚度和面积对人耳听力的影响

依据临床健康志愿者右耳的CT扫描结果，将CT扫描数据数值化导入PATRAN软件进行人耳三维有限元模型的重建，并用NASTRAN软件对该模型进行频率响应分析。通过对正常人耳结构进行频率响应分析得出数据与实验数据吻合，验证了模型的正确性。结合临床中耳炎病症实际情况，研究细菌生物膜的成长阶段对人耳听力的影响。结果表明：在不同声压相同的频率段，细菌生物膜的厚度变化对人耳听力的影响是相同的。在相同声压不同频率段，细菌生物膜的厚度增加会引起镫骨振幅和速度降低，在较低频率段镫骨振幅和速度下降幅度较大，下降的最大值为1.64 dB；在较高频率段镫骨振幅和速度下降幅度较小，下降的最大值为1.04 dB。在不同声压作用下，在相同的频率段细菌生物膜的面积增加会引起镫骨振幅和速度降低。在100～1 000 Hz频率段镫骨振幅和速度的下降幅度较小，下降的最大值为0.18 dB。在1000～10 000 Hz频率段镫骨振幅和速度的下降幅度较大，下降的最大值为2.26 dB。细菌生物膜厚度或面积增加都会使人耳听力下降，厚度增加在低频时比高频时下降更多，而面积增加则刚好相反。

The Effects of Bacterial Biofilm Thickness and Area on Hearing

According to CT images of the right ear from a healthy volunteer, a 3D finite element model of the ear was established in PATRAN software by a self compiling program. Then NASTRAN software was used to make frequency response analysis for human ear finite element model. The model was carried through a frequency response analysis of normal ear structure and confirmed by the consistency in the calculated and experimental data after comparison. Combined with the clinical symptoms of otitis media, the effects of variation in thickness and area on hearing ability in the growth stage of bacterial biofilm were investigated. Results show that in the same frequency bands, the thickness variation of bacterial biofilm had the same regular pattern in the effects on hearing ability under different pressures. Thickness increase of bacterial biofilm decreased the stapes amplitude and stapes velocity in the same frequency band. The descend range of hearing ability was different in various frequency bands under the same pressure. The stapes amplitude and stapes velocity declined largely in low frequency band, the maximum value of the decline was 1.64 dB, and declined little in high frequency band. The maximum value of the decline was 1.04 dB. The area increase of bacterial biofilm decreased the stapes amplitude and stapes velocity in the same frequency band. The descend range of hearing ability was different in various frequency bands under the same pressure. The stapes amplitude and stapes velocity declined little in frequency band from 100-1 000 Hz, The maximum value of the decline was 0.18 dB, and declined largely in frequency band from 1 000 Hz to 10 000 Hz. The maximum value of the decline was 2.26 dB. In conclusion, the increase of thickness or area of bacterial biofilm caused the decline of hearing ability. The increase in the thickness caused more decline in the low frequency band than in the high frequency band, while the area increase caused opposite results.