Abstract:

Objective To construct a swallowing dynamic model for simulating dysphagia caused by reduced tongue movement amplitude.

Methods A swallowing dynamic model was established based on medical imaging data from CT and videofluoroscopic swallowing study (VFSS). The finite element method was used to simulate soft tissues, while the smoothed particle hydrodynamics method (SPH) was used to simulate bolus. The model's posture at each time point was compared with the imaging data of VFSS from twelve patients with dysphagia, and a normalization method was used for quantitative evaluation of the model's validity. By adjusting the tongue movement amplitude under different viscosity conditions, the role of tongue movement in the swallowing process was investigated, and the swallowing safety and efficiency were assessed.

Results The tongue posture and bolus trajectory presented by the swallowing dynamic model were consistent with the VFSS imaging. The brightness in the epiglottis area in VFSS images correlated with the equivalent brightness of SPH particles in the simulation results (r = 0.97). As the tongue movement amplitude reducing by 20%, the number of aspirated particles, swallowing efficiency and the average velocity of bolus particles in the oropharyngeal cavity all performed well. Pudding-like fluids exhibited favorable swallowing characteristics even when tongue movement amplitude reducing significantly.

Conclusion The swallowing dynamic model can simulate the human swallowing process, providing good support for rehabilitation training of patients with dysphagia and the development of specialized medical foods, demonstrating significant potential for clinical applications.

Key words: dysphagia, computer simulation, tongue movement, bolus viscosity