Lingual Mechanical Function During Swallowing

描述（由申请人提供）：人的舌头是一个复杂配置的肌肉器官，在吞咽的生理行为中起着至关重要的作用。在正常吞咽期间，舌头首先配置，然后将摄入的食团从口腔逆行推进到咽部。从临床角度来看，舌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、帕金森病和痴呆症相关，并且是这些患者群体中营养受损和吸入性肺炎风险增加的原因。尽管如此，对舌肌结构对生理功能的贡献方式的了解很少。舌力学的研究长期以来一直受到组织的复杂肌结构及其材料特性的阻碍。因此，机械功能不能仅仅从形状的整体变化来确定，而是需要研究壁内动力学。我们的总体假设是，舌头的功能是肌肉的液压调节器，这是人体中的一种独特结构，具有创造运动并为该运动提供骨骼支撑的能力。为了在人类吞咽的情况下测试这一假设，我们从材料连续体的角度考虑了舌头，并因此根据局部纤维组织和应变描绘了组织。本计画将研究人类吞咽动作之三维肌构筑与局部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辨别体内的肌结构和区域力学模式。在具体目标1中，将通过描述磁共振成像得出的局部二阶扩散张量来研究舌的三维肌结构。在特定目标2中，将通过将结构测量与标记磁化相关联来确定与吞咽相关的肌纤维结构和局部应变之间的定量关系。在特定目标3中，将通过在不同负载条件下组合扩散张量和标记磁化成像来研究对不同团注体积和粘度的局部机械适应性。该项目将导致对人类舌头结构-功能关系的更好理解，以及相关的人类肌肉自动调节器。预计这种理解将导致口咽吞咽困难患者的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.