基于非线性方法探讨病嗓音和病理声带振动的发生机制

Pathological vocal fold vibrations often exist in patients with severe voice disorders. Traditional methods, including videostroboscopy, rely on linear relationships and are often invalid when evaluating patients with dysphonia. However, nonlinear methods have been shown to effectively quantify abnormal voice for a variety of disorders and severities of disorder, and have been shown by our previous experiments to reliably distinguish between normal and disordered voice production. There is a relationship between the nonlinear parameter values and the size of a vocal lesion. Therefore, it would be of great scientific and clinical value to determine the critical point at which linear methods are no longer valid and nonlinear methods must be employed. This critical point could be characterized by type of pathology, severity of pathology, or impact on laryngeal biomechanics. We will conduct a series of studies to investigate this phenomenon. First, we will build a nonlinear finite element model of the vocal folds to explore the nonlinear dynamic mechanism of vocal fold vibration. We will also explore the critical points of nonlinear parameters at the onset of chaos. Then, we will use an excised canine larynx model to investigate the relationships between lesion size, subglottal pressure driving force, nonlinear voice characteristics, and mucosal wave properties. We will also use the excised canine larynx model to evaluate treatments for vocal fold lesions and validate the nonlinear finite element model. Lastly, we will use nonlinear dynamic and perturbation methods to quantify voice production in patients with voice disorders. These three experiments will explore the mechanism of nonlinear dynamic voice production in patients with voice disorders. This project will have a great value and potential benefit in voice science and voice medical practice.

病嗓音和病理声带振动存在紊乱现象，传统的傅里叶方法和喉镜图像定性分析易致偏差，非线性方法能有效分析病嗓音和病理声带振动的紊乱特性。我们前期的嗓音非线性分析发现嗓音和声带振动的非线性参数的变化与声带病变程度具有相关性，因此探索病嗓音的非线性特性、声带病变（性质及程度）和生物力学变化导致嗓音及声带振动发生紊乱质变的非线性参数临界值极具重要性。我们拟通过以下方法验证：①采用有限元声带模型模拟声带发音，通过改变模型参数及边界条件，寻找条件改变引起声带振动及嗓音紊乱的非线性参数临界值。②采用离体狗喉发声实验，模拟疾病及治疗模型，定量分析不同狗喉模型的嗓音非线性特性和粘膜波紊乱动态规律，并验证数值模型。③临床测量入选声带疾病的病变程度，探讨声带病变程度对嗓音和声带振动非线性特性的影响，探索嗓音紊乱临界点。本课题尝试阐明病嗓音和病理声带振动的非线性动力学机理，具有重大的科学意义和潜在的临床应用价值。

背景：前期研究显示病嗓音和病理声带振动存在紊乱现象，传统的傅里叶方法和喉镜图像定性分析易致偏差，非线性方法能有效分析病嗓音和病理声带振动的紊乱特性。.研究方向：探索病嗓音的非线性特性；声带病变和生物力学变化导致嗓音及声带振动发生紊乱质变的非线性参数临界值。.主要内容：1）采用非线性方法研究声门下压(SGP)对离体狗喉发声的影响，研究声带振动的非线性机制；2）构建离体狗喉声门闭合不全(GI)模型，探索声门闭合不全程度对发声的影响；3）构建离体狗喉声门上结构(含室带、喉室腔、会厌)挤压模型，探究声门上结构在发声中的反向作用。4）设计并定义声门下方收敛角度(SCA)，结合气道及声带模型进行测量，研究SCA改变可能对嗓音功能的影响。.结果：1）离体狗喉发声信号的不规则性与SGP大小有关；非线性方法分析不规则信号较扰动方法更具敏感性。2）SGP和GI对声信号、黏膜波及PTP有显著影响，当声门闭合程度为2-3mm时，声信号及黏膜波紊乱出现明显变化。3）声带振动与SCA有关，GI增加导致该角度增大。4）室带肥厚对声音能量分布及质量改变具有显著影响。5）会厌角度在离体狗喉发声和共鸣中起着重要作用，会厌角度大时，气流率变大，F1及F4减小。.关键数据：1）离体狗喉SGP为4kpa时较SGP为2kpa时驱动声带振动时发声信号的相空间重构更为复杂，关联维D2在更大处出现收敛；2）SGP和GI的单一变化对jitter的影响具有统计学意义（P<0.05）。在SGP 1.5-3.0Kpa区间内，振幅随着声门闭合不全程度的增加而减低，有统计学意义（P<0.05）。3）三种狗喉室带不同肥厚模型与SGP对声带振动的影响，主效应均有统计学意义（P＜0.0001）；正常狗喉和Ⅱ度肥厚模型相比，声压级的增加具有统计学意义（P＜0.05）。4）SCA可以通过模型准确测量,随声带闭合不全程度增加而增加，三组程度的均数分别为33.4°、55.03°及75.02°，差异具有统计学意义（P<0.01）。.科学意义：完善了声带振动机理的研究，揭示病嗓音和病理声带振动的病理现象及紊乱点，为嗓音疾病的治疗提供理论基础。