目的 探究双耳3对半规管在感受有角运动时力学行为表达的规律。方法 采用有限元法数值模拟一例健康人头部水平正弦转动时左、右耳3对半规管的力学响应。结果 各平衡感受器嵴顶局部位移响应随着嵴顶位置改变而变化,但是3对嵴顶的体积应变响应是规律的,每对嵴顶均以与激励相同的频率等幅度膨胀或收缩。水平、前、后半规管3个嵴顶的体积应变幅值绝对值的比值恒定,近似为1.00︰0.80︰1.72。此外,水平半规管和前半规管嵴顶体积应变响应的相位相同,且与头转动速度的相位约相差14.4°,与后半规管嵴顶体积应变响应的相位相差180°。结论 嵴顶体积应变可以较好地表征3对半规管感受有角运动的规律,其幅值、频率和相位可以分别反映刺激角速度的幅值、频率和相位,这一规律为进一步建立前庭眼反射的数量依存关系奠定基础,同时为眼震检查定量评估前庭功能提供理论依据。
Objective To study the general mechanical behavior pattern of sensing angular velocity by 3 pairs of human semicircular canals. Methods Sinusoidal head rotation of a healthy subject was simulated by finite element method to analyze the dynamic responses in the above 3 pairs of canals in the left and right inner ear. Results Compared with the complicated node displacement distribution, the volumetric strain distribution of cupula was regular. Specifically, each pair of cupulae expanded or contracted within the same amplitude with the same response frequency to the angular velocity. The ratio of absolute volumetric strain among the horizontal semicircular canal cupula (HC cupula), the anterior semicircular canal cupula (AC cupula), and the posterior semicircular canal cupula (PC cupula), was approximately 1.00︰0.80︰1.72, which kept constant. In addition, the volumetric strain of HC cupula was in phase with that of AC cupula, but showing 14.4° out of phase with the angular velocity, and 180° out of phase with that of PC cupula. Conclusions The volumetric strain of cupula can preferably characterize the directional coding function of semicircular canal, and the amplitude, frequency and phase of the cupular volumetric strain can encode those of the stimulated angular velocity, respectively. These results will lay the foundation for establishing quantitative relationship of vestibulo-ocular reflex, and provide theoretical references for quantitative assessment for vestibular function by nystagmus examination.