中耳畸形对能量吸收率影响的数值研究

为了研究中耳畸形对能量吸收率的影响,本文基于前期所建人耳有限元模型,构建了一个能够模拟人耳能量吸收的力学模型,并利用两组实验数据验证了该模型。基于该模型,通过改变相应组织的结构和材料属性,模拟了砧镫关节缺失、砧骨固定和锤骨固定、镫骨固定这三类常见的中耳畸形;对比分析这三类畸形相应的能量吸收率,研究了中耳畸形对能量吸收率的影响。结果表明:砧镫关节缺失会使能量吸收率在1000 Hz附近显著增大。砧骨固定和锤骨固定会使能量吸收率在低频阶段急剧减小,且在1000 Hz以下低于10%;与此同时,能量吸收率的峰值移向更高频率。对于这两类中耳畸形,在宽频声导抗测试中具有较为明显的特征。而镫骨固定会使能量吸收率在低频段减小、中频段增大,但变化程度较小,在宽频声导抗测试中无明显特征。本文研究结果或可为临床上中耳畸形的宽频声导抗诊断提供一些理论参考。

Numerical study on the effect of middle ear malformations on energy absorbance

In order to study the effect of middle ear malformations on energy absorbance,we constructed a mechanical model that can simulate the energy absorbance of the human ear based on our previous human ear finite element model.The validation of this model was confirmed by two sets of experimental data.Based on this model,three common types of middle ear malformations,i.e.incudostapedial joint defect,incus fixation and malleus fixation,and stapes fixation,were simulated by changing the structure and material properties of the corresponding tissue.Then,the effect of these three common types of middle ear malformations on energy absorbance was investigated by comparing the corresponding energy absorbance.The results showed that the incudostapedial joint defect significantly increased the energy absorbance near 1000 Hz.The incus fixation and malleus fixation dramatically reduced the energy absorbance in the low frequency,which made the energy absorbance less than 10%at frequencies lower than 1000 Hz.At the same time,the peak of energy absorbance shifted to the higher frequency.These two kinds of middle ear malformations had obvious characteristics in the wideband acoustic immittance test.In contrast,the stapes fixation only reduced the energy absorbance in the low frequency and increased energy absorbance in the middle frequency slightly,which had no obvious characteristic in the wideband acoustic immittance test.These results provide a theoretical reference for the wideband acoustic immittance diagnosis of middle ear malformations in clinic.