Lingual Mechanical Function During Swallowing

描述（由申请人提供）：人类舌头是一个结构复杂的肌肉器官，在吞咽的生理行为中起着至关重要的作用。在正常的吞咽过程中，舌头首先调整形状，然后将摄入的物质从口腔逆行推进到咽部。从临床角度来看，语言功能障碍在老年人中非常常见，与常见的神经系统疾病（如中风、帕金森病和痴呆）有关，并且是这些患者群体营养受损和吸入性肺炎风险增加的原因。尽管如此，对于舌部肌肉结构对生理功能的影响，人们的理解仍然很少。长期以来，舌力学的研究一直受到组织复杂的肌肉结构及其材料特性的阻碍。因此，力学功能不能仅仅从整体形状的变化来确定，而需要研究内部动力学。我们的总体假设是，舌头的功能是肌肉的静水器，是人体中一种独特的结构，既能创造运动，又能为运动提供骨骼支撑。为了在人类吞咽的情况下验证这一假设，我们从一个物质连续体的角度来考虑舌头，从而从局部纤维组织和张力的角度来描述组织。本项目将研究人体吞咽过程中三维肌肉结构与区域力学之间的定量关系。我们的实验方法使用非侵入性核磁共振成像技术来识别体内肌肉结构和区域力学的模式。在具体目标1中，舌头的三维肌肉结构将通过磁共振成像衍生的局部二阶扩散张量的描述来研究。在Specific Aim 2中，与吞咽相关的肌肉纤维结构和区域应变之间的定量关系将通过结构测量与标记磁化的联系来确定。在Specific Aim 3中，将通过联合扩散张量和标记磁化成像研究不同载荷条件下不同体积和粘度的区域机械适应性。这个项目将有助于我们更好地理解人类舌头的结构-功能关系，以及相关的人类肌肉静力学。预计这种理解将导致口咽吞咽困难患者病理性舌功能的新假设。

DESCRIPTION (provided by applicant): The human tongue is an intricately configured muscular organ that plays a vital role during the physiological act of swallowing. During normal deglutition, the tongue first configures, then propels the ingested bolus from the oral cavity retrograde to the pharynx. From a clinical perspective, disorders of lingual function are exceedingly common in the elderly, in association with common neurological diseases, such as stroke, Parkinson's disease, and dementia, and are responsible for impaired nutrition and increased risk of aspiration pneumonia in these patient populations. Notwithstanding, there is minimal understanding of the way in which lingual muscular structure contributes to physiological function. The study of lingual mechanics has long been hampered by the complex myoarchitecture of the tissue and its material properties. As a result, mechanical function cannot be determined solely from global changes of shape, but necessitates the study of intramural dynamics. Our overall hypothesis is that the tongue functions as a muscular hydrostat, a unique structure in the human body, with the ability to both create motion and to provide the skeletal support for that motion. In order to test this hypothesis in the setting of human swallowing, we have considered the tongue from the perspective of a material continuum, and have thus depicted the tissue in terms of local fiber organization and strain. This project will study the quantitative relationship between three-dimensional myoarchitecture and regional mechanics during human swallowing. Our experimental approach uses non-invasive nuclear magnetic resonance imaging techniques to discern patterns of myoarchitecture and regional mechanics in vivo. In Specific Aim 1, the three-dimensional myoarchitecture of the tongue will be studied through the depiction of the local second order diffusion tensor derived from magnetic resonance imaging. In Specific Aim 2, the quantitative relationship between muscle fiber architecture and regional strain in association with swallowing will be determined by linkage of the structural measures with tagged magnetization. In Specific Aim 3, the regional mechanical adaptation to varying bolus volume and viscosity will be studied through combined diffusion tensor and tagged magnetization imaging under varying load conditions. This project should result in an improved understanding of structure-function relationships for the human tongue, and related human muscular hydrostats. It is anticipated that this understanding will result in novel hypotheses of pathological lingual function for patients with oropharyngeal dysphagia.