息肉与麻痹喉声源分类中非线性动力学发声系统模型研究

Study on the model of nonlinear dynamics phonation system for the classification of polyps and paralysis phonation

提出一种非线性动力学建模仿真发声系统,分类息肉和麻痹喉声源的方法,为声带疾病分类时参数选择提供了依据。首先介绍息肉和麻痹声带力学模型,耦合声门气流产生喉声源,求取喉声源频率(基频)、基频微扰;提出用庞加莱截面,分岔图对模型振动进行非线性分析;改变声带病理参数及声门下压,分析频率参数和混沌参数李雅普诺夫指数的变化。仿真实验结果表明,声带麻痹减小了发声基频,且只在一定压力范围内出现混沌振荡;息肉声带的混沌则分布在整个压力范围内。根据最大李雅普诺夫指数随声门下压变化的差异性分布,有助于识别并分类声带息肉和声带麻痹。

In order to provide the basis for parameter selection of vocal diseases classification, a nonlinear dynamic modeling method is proposed. A biomechanical model of vocal cord with polyps and paralysis is introduced, which coupled to glottal airflow to produce laryngeal sound source. And then the fundamental frequency and its perturbation parameters are solved. Poincare section and bifurcation diagrams are applied to nonlinear analysis of model vibration. The relationship between pathological parameters with different sub-glottal pressure and the flmdamental frequency included Lyapunov exponents are analyzed. The results show that, vocal cord paralysis reduces the fundamental fre- quency, in which the chaos occurs only within a certain pressure range; while vocal cord with polyps don＇t reduces the fundamental frequency, in which the chaos is distributed throughout the entire range. Therefore this study is helpful for classification of polyps and paralysis by the acoustic diagnoses.