Computational modeling of child’s swallowing to simulate choking on toys

ABSTRACT

Choking occurs more frequently in children and senior citizens than in other groups. Obstruction materials are varied, including food or foreign bodies such as toys and coins. The number of choking accidents has not decreased because its mechanism remains unclear; the manner in which such accidents occur cannot be observed. The purpose of this study is to visualize choking on toys by using a computer simulation, Swallow Vision®, after creating a new child model of swallowing. An organ model for the simulation was created from the CT of a 9-month-old boy and videofluorographic images during swallowing for a 9-month-old girl. The organ models were defined as hyperelastic and contained particles that moved by forced displacement. The toy models were spheres with diameters of 10 and 15 mm and different coefficients of friction and restitution. The applied calculation method was the Hamiltonian Moving Particle Simulation. The results demonstrated that the simulation could visualize how a toy model obstructed the upper airway in the pharynx and larynx. Moreover, the ball size and the coefficients of friction and restitution affected the site obstructed. As choking accidents were successfully visualized using the Swallow Vision®, The computer simulation is expected to advance research on understanding the choking mechanism.

KEYWORDS:

• Choking
• toy
• computer simulation
• swallowing simulator

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Consumer Affairs Agency of Japanese Government [2017].

Notes on contributors

Yukihiro Michiwaki

Yukihiro Michiwaki is Director of Oral Surgery and Special Dentistry Division of Japanese Red Cross Musashino Hospital in Japan. His clinical field covers operations for oral diseases as well as rehabilitation for swallowing and speech disorders. He is also the president of non-profit organization, Enyukai, established to support caregivers and people with swallowing difficulties since 2006. He perform clinical researches on developing tools to treat swallowing difficulties. Beside from the clinical research he has been conducting a basic research of numerical simulation on revealing biomechanism about swallowing, aspiration and choking.

Takahiro Kikuchi

Takahiro Kikuchi is Research Fellow of Division of Oral Surgery, Japanese Red Cross Musashino Hospital, Japan. He researches methods of modeling, numerical simulation, and visualization for swallowing. He is also the secretary of Nonprofit Organization Enyukai, working to support people with swallowing disorders as well as health care workers.

Tetsu Kamiya

Tetsu Kamiya is a manager of R&D division at Meiji Co. ltd, Japan. His background is process engineering and process development for dairy and confectionary. His main research filed is the mixing, the tableting, and the numerical simulation. His recent interest is the food oral processing.

Yoshio Toyama

Yoshio Toyama is a manager of R&D division at Meiji Co. ltd, Japan. His background is product development of dairy products especially the medical nutrition for elderly person. His main research filed is food oral processing and controlling and design of physical properties.

Motoki Inoue

Motoki Inoue is a researcher of R&D division at Meiji Co. ltd, Japan.He researches the relationship between food properties and food oral processing. He is also interested in food comfort and safety.

Keigo Hanyuu

Keigo Hanyuu is Associate Scientist of R&D division at Meiji Co. ltd, Japan. His background is process engineering and process development for dairy and confectionary. His actual research filed is the tableting technology and the particle simulation with DEM method. His recent interest is the science base food design.

Megumi Takai

Megumi Takai is a researcher of R&D division at Meiji Co. ltd, Japan. Her background is sensory technology for food products. Her main research filed is evaluation technology. Her recent interest is the sensitivity engineering and the normalization of the characteristic value of food with the tribology and the visualization technologies.

Seiichi Koshizuka

Seiichi Koshizuka is a professor of the Department of Systems Innovation, the University of Tokyo from 2004. His research interests are computational fluid dynamics, particle methods, computational mechanics and verification and validation (V&V). He is a member of the Japan Society for Computational Engineering and Science (JSCES), the Japan Society of Mechanical Engineers (JSME), the Atomic Energy Society of Japan (AESJ), etc. He is one of the co-authors of book “Moving Particle Semi-implicit Method” Academic Press (2018).