A planar finite element model of bolus containment in the oral cavity.

As individuals age, one of the objective changes that occurs in the oropharyngeal swallow is the development of a delay between bolus entry into the pharynx and the initiation of airway protection mechanisms. For longer delays, this phenomenon is sometimes referred to as "premature spillage," and it has been suggested that such spillage, which is a risk factor for dysphagia, may be associated with pre-swallow lingual gestures, or "tongue pumping." The goal of the current study was to develop a simplified two-dimensional computational model of the oropharynx to simulate the containment of a Newtonian fluid bolus within the oral cavity in response to a given pattern of lingual gestures for different viscosities. An arbitrary Lagrangian-Eulerian simulation was performed using the commercial finite element software package, LS-Dyna. It was found that for a given lingual motion, higher viscosity Newtonian boluses, consistent with those offered therapeutically, were able to be contained within the simulated oral cavity while a lower viscosity bolus would be "spilled," suggesting a potential mechanisim by which thickened liquids may reduce aspiration. Although the current data must be validated with more realistic, three-dimensional geometric information and for a wider range of bolus rheologies, they represent an exciting first step towards realistic modeling of oropharyngeal bolus flow.