The mechanism of sensing postural changes in human ears by numerical simulation / 医用生物力学

ABSTRACT

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.