MATHEMATICAL-MODELING OF NORMAL PHARYNGEAL BOLUS TRANSPORT - A PRELIMINARY-STUDY

Dysphagia (difficulty in swallowing) is a common clinical symptom asso ciated with many diseases, such as stroke, multiple sclerosis, neuromu scular diseases, and cancer. Its complications include choking, aspira tion, malnutrition, cachexia, and dehydration. The goal in dysphagia m anagement is to provide adequate nutrition and hydration while minimiz ing the risk of choking and aspiration. It is important to advance the individual toward oral feeding in a timely manner to enhance the reco very of swallowing function and preserve the quality of life. Current clinical assessments of dysphagia are limited in providing adequate gu idelines for oral feeding. Mathematical modeling of the fluid dynamics of pharyngeal bolus transport provides a unique opportunity for study ing the physiology and pathophysiology of swallowing. Finite element a nalysis (FEA) is a special case of computational fluid dynamics (CFD). In CFD, the flow of a fluid in a space is modeled by covering the spa ce with a grid and predicting how the fluid moves from grid point to g rid point. FEA is capable of solving problems with complex geometries and free surfaces. A preliminary pharyngeal model has been constructed using FEA. This model incorporates literature-reported, normal, anato mical data with time-dependent pharyngeal/upper esophageal sphincter ( UES) wall motion obtained from videofluorography (VFG). This time-depe ndent wall motion can be implemented as a moving boundary condition in the model. Clinical kinematic data can be digitized from VFG studies to construct and test the mathematical model. The preliminary model de monstrates the feasibility of modeling pharyngeal bolus transport, whi ch, to our knowledge, has not been attempted before. This model also a ddresses the need and the potential for CFD in understanding the physi ology and pathophysiology of the pharyngeal phase of swallowing. Impro vements of the model are underway. Combining the model with individual ized clinical data should potentially improve the management of dyspha gia.