In the United States, 15-30 % of the 44 million individuals currently over the age of 60 are estimated to have dysphagia (a general term for swallowing disorders), along with an estimated 50 % of nursing home patients. In addition to the profound effect that swallowing disorders have on an individual's quality of life, these disorders also pose significant health risks. For example, consider the phenomena of aspiration, in which ingested material enters the trachea and lungs rather than the esophagus and gastrointestinal tract. This behavior may transport oral bacteria to the lungs and is a risk factor for aspiration pneumonia, a serious and often life-threatening health concern for the institutionalized and hospitalized geriatric population. During the normal swallow, the sequential contact of the tongue against the palate propels swallowed material out of the oral cavity and through the pharynx. Contraction of the pharyngeal musculature then moves this material into the esophagus. Flow in response to these propulsive forces, however, depends on the physical properties of the bolus, such as viscosity and density. The long-term goal of the PI's research program is to apply modern computational modeling strategies to the study of oropharyngeal swallowing. Given the largely mechanical nature of the swallowing process, the development and application of such computational tools has the potential to enhance our understanding of both oropharyngeal swallowing mechanics as well as therapeutic and diagnostic tools. Given the complexities associated with simulating this process, we are proposing a conservative research plan, which focuses on the development of a two-dimensional computer simulation of oropharyngeal swallowing. Given that this portion of the swallow may be described as the highly transient flow of an air-liquid mixture through a complex geometry with time-dependent boundaries, we aim to develop an adaptive finite element model that is able to simulate arbitrary fluid-like materials,. If successful, further work will extend the mode to three dimensions. ? Public Health Relevance: In the United States, 15-30 % of the 44 million individuals currently over the age of 60 are estimated to have dysphagia (a general term for swallowing disorders), along with an estimated 50 % of nursing home patients. Although computer modeling has been extensively applied to other physiological system, such as cardiovascular and neurologic, very few models have been developed for swallowing. The current proposal addresses the development of such a computer based modeling tool to predict the motions of a fluid bolus as it traverses the oropharyngeal cavity. Our long-term vision for this program is two-fold. First, we envision an analysis tool to aid clinicians and scientists working on bolus transport in understanding the basic mechanics of oropharyngeal swallowing. This will lead naturally to an optimization tool, which could be added to the current arsenal of tools with which to analyze available diagnostic and therapeutic procedures and to develop new ones. ? ? ?
