Kinematic Modeling of Asymmetric Vocal Fold Vibration

描述（由申请人提供）：该项目的目标是更清楚地了解声带的结构和振动不对称如何影响声带功能的临床测量和发声障碍的严重程度评级。这种不对称是许多声音障碍的关键特征，包括单侧声带运动障碍（VFMI），并可能导致呼吸语音质量的感知。临床声音评估和管理的基础是了解声带振动模式如何与声音功能测量和感知相关。然而，由于难以成像声带振动的三维运动特征，无法系统地改变振动的各个组成部分，以及将声门源（即声带振动）与空气动力和声学信号的过滤器（即声道）特征分离的挑战，确定特定不对称如何影响声音输出在人类受试者中受到限制。描述这些因果关系可以立即影响声带功能测量的临床应用和解释，以及对继发于VFMI的呼吸性语音患者的治疗决策。本研究的方法是使用声带振动的运动学模型，该模型将允许对声带内收、内侧表面鼓胀、振动节点、相位和基频进行微分左/右控制。声带模型将与语音产生的综合模型耦合，通过该模型可以模拟声门面积、声带接触面积、声门气流和输出压力，就像人类说话一样。在系统中包含气管和声道，可以对空域对输出信号的影响进行额外的测试。在本项目中，选择用于系统修饰的声带结构和振动参数将与VFMI报告的变化一致，并将测试手术和行为管理引起的声带和声道变化。本研究将以三个假设为指导：1)声带结构和振动不对称的影响可以通过一套临床可行的声学和空气动力学发声功能测量来表征；2)结构和振动不对称的程度将与发声障碍的严重程度等级直接相关；3)声门上声道的尾咽段收缩将降低发声障碍的程度，无论是通过发声功能测量还是基于感知的严重程度等级。为了解决这些假设，我们设计了三个特定的目标：1)基于47种不对称设置组合生成模拟信号数据库，这些组合包括声带内收、内侧表面鼓胀、振动节点、相位和基频。对于元音/a/， /i/， /u/和/ae/以及收缩的尾咽，将重复模拟。2)从Aim 1中产生的每个信号收集中，测量一系列临床可行的运动学、空气动力学和声学测量。3)进行感知实验，评估Aim 1中产生的信号所代表的语音障碍的严重程度。

DESCRIPTION (provided by applicant): The goal of this project is to develop a clearer understanding of how structural and vibratory asymmetry of the vocal folds affects both clinical measures of vocal function and severity ratings of dysphonia. Such asymmetries are key features underlying many voice disorders, including unilateral vocal fold motion impairment (VFMI), and likely contribute to the perception of breathy voice quality. Clinical voice evaluation and management are based in understanding how vocal fold vibration patterns are related to vocal function measures and perception. Determining how specific asymmetries contribute to the vocal output, however, is limited in human subjects by difficulty imaging the three-dimensional movement characteristics of vocal fold vibration, inability to systematically vary individual components of vibration, and challenges of separating the glottal source (i.e., vocal fold vibration) from filter (i.e., vocal tract) characteristics of aerodynamic and acoustic signals. Delineating these causal relationships can immediately impact the clinical use and interpretation of vocal function measures and treatment decisions for patients with breathy voice secondary to VFMI. The approach for this research is to use a kinematic model of vocal fold vibration that will allow for differential left/right control of vocal fold adduction, medial surface bulging, vibratory nodal point, phase, and fundamental frequency. The vocal fold model will be coupled to a comprehensive model of speech production, with which glottal area, vocal fold contact area, glottal airflow and output pressure can be simulated as if they were produced by a human talker. The inclusion of a trachea and vocal tract in the system allows for additional testing of the effect of airspace on the resulting output signals. For this project, the vocal fold structure and vibratory parameters selected for systematic modification will be consistent with changes reported in VFMI, and vocal fold and vocal tract changes occurring with surgical and behavioral management will be tested. The research will be guided by three hypotheses: 1) the effects of structural and vibratory asymmetry of the vocal folds can be characterized with a set of clinically-feasible acoustic and aerodynamic measures of vocal function, 2) the degree of structural and vibratory asymmetry will be directly related to severity ratings of dysphonia, and 3) constriction of the epilaryngeal section of the supraglottal vocal tract will decrease the degree of dysphonia registered both by vocal function measures and perceptually-based severity ratings. Three specific aims are designed to address these hypotheses: 1) To generate a database of simulated signals based on 47 combinations of asymmetric settings for vocal fold adduction, medial surface bulging, vibratory nodal point, phase, and fundamental frequency. The simulations will be repeated for the vowels /a/, /i/, /u/, and /ae/ and for a constricted epilarynx. 2) To measure, from each collection of signals generated in Aim 1, a battery of clinically-feasible kinematic, aerodynamic, and acoustic measures. 3) To conduct perceptual experiments that assess the severity of the dysphonia represented by the signals generated in Aim 1. PUBLIC HEALTH RELEVANCE: Vocal fold motion impairment with asymmetric vocal fold vibration leads to a breathy, weak voice, which is undesirable for people in many professions such as teaching, law enforcement, clergy, medicine, or the military. Breathy voice caused by asymmetric vocal fold vibration becomes a public health concern when it interferes with an individual's ability to communicate at work and leads to withdrawal from social situations. Better understanding of the how specific asymmetries contribute to voice quality will lead to more efficient evaluation and treatment.