BIOMODE : Biomechanical Modeling of Deglutition.

Deglutition or swallowing is the process in which, coordinate motion of several muscles transport the food bolus, from the oral cavity to the low esophageal sphincter. This process is composed by several stages such as food bolus preparation, propulsion, pharyngeal and esophageal stages. In general, any physiological or pathological affection to this coordinated process is known as dysphagia, and it is associated with stroke survivors, Parkinson, multiple sclerosis, and in general aged related diseases. Dysphagia severely affects the life quality of the patient and can cause death, mainly to the effects of food bolus aspiration (aspiration pneumonia). This research was done in collaboration with GIPSA-LAB, who work under the macro project “eSwallHoome”, funded by the French Agence Nationale de la Recherche (FANR) The research has as the main objective to study and explain the mechanisms of breathing and swallowing via in vivo, in vitro and in simulacra approaches. The project Biomechanical modeling of deglutition (Biomode) is focused on modeling the behavior of food bolus during the swallowing process. This project aimed to contribute to the understanding of the physical phenomena underlying swallowing. Particularly, this project developed tongue’s elastic models and simplified models related with the interaction of a liquid, Newtonian food bolus and the oral cavity during the oral propulsion stage. The approach of the study was both experimental and computational. The highlights of the project included: 1. Mechanical models of tongue’s motion and deformation based on hyperelastic muscle’s properties. 2. Numerical tools for the simulation of large displacement models coupled with nonlinear elastic materials that would potentially describe the fluid structure interaction during oral propulsion stage and also compare the results with experimental data taken from a simplified bench and 3. Generation of simplified dimensionless models of oral propulsion stage based on the interaction between a Newtonian fluid food bolus and the physiological accurate tongue’s dynamics, responsible for oral propulsion. During the project, GIPSA-Lab/TIMC-IMAG laboratories from Grenoble and Nicolas Hermant from Universidad del Valle, developed a full 3D nonlinear elastic model using finite element method and high displacement models of human tongue biomechanics. Also, a basic fluid structure interaction with Newtonian fluid and a nonlinear latex membrane with high displacement model was implemented in ANSYS® Workbench. Finally, two novel simplified dimensionless models for estimation of fluid/tongue interaction load as function of flow regime and fluid food bolus properties were proposed

Biomechanical Models of Human Upper and Tracheal Airway Functionality

The respiratory tract, in other words, the airway, is the primary airflow path for several physiological activities such as coughing, breathing, and sneezing. Diseases can impact airway functionality through various means including cancer of the head and neck, Neurological disorders such as Parkinson\u27s disease, and sleep disorders and all of which are considered in this study. In this dissertation, numerical modeling techniques were used to simulate three distinct airway diseases: a weak cough leading to aspiration, upper airway patency in obstructive sleep apnea, and tongue cancer in swallow disorders. The work described in this dissertation, therefore, divided into three biomechanical models, of which fluid and particulate dynamics model of cough is the first. Cough is an airway protective mechanism, which results from a coordinated series of respiratory, laryngeal, and pharyngeal muscle activity. Patients with diminished upper airway protection often exhibit cough impairment resulting in aspiration pneumonia. Computational Fluid Dynamics (CFD) technique was used to simulate airflow and penetrant behavior in the airway geometry reconstructed from Computed Tomography (CT) images acquired from participants. The second study describes Obstructive Sleep Apnea (OSA) and the effects of dilator muscular activation on the human retro-lingual airway in OSA. Computations were performed for the inspiration stage of the breathing cycle, utilizing a fluid-structure interaction (FSI) method to couple structural deformation with airflow dynamics. The spatiotemporal deformation of the structures surrounding the airway wall was predicted and found to be in general agreement with observed changes in luminal opening and the distribution of airflow from upright to supine posture. The third study describes the effects of cancer of the tongue base on tongue motion during swallow. A three-dimensional biomechanical model was developed and used to calculate the spatiotemporal deformation of the tongue under a sequence of movements which simulate the oral stage of swallow

Comparison of In Vivo Simulation Training Compared to Video Simulation Training for Identifying Clinical Markers of Distress When Feeding Preterm Infants

Preterm infants have multiple health complications due to their underdeveloped neurological systems. Bottle-feeding difficulties are one complication that leads to pulmonary illness secondary to aspiration. Preterm infants exhibit clinical markers when experiencing distress during bottle-feeding. Training caregivers to identify clinical markers reduces the risk for aspiration. Simulation training provides a safe learning environment without harming patients. Twenty-two speech-language pathology and pre-requisite students divided into two simulation groups, video-simulation (N=12) and in-vivo simulation (N=10), were trained to document clinical markers of distress exhibited by preterm infants and make clinical judgments about bottle-feeding. Students rated their levels of anxiety during simulation training. Results revealed that students trained using video-simulation performed with higher clinical judgment scores and lower anxiety levels than students who received in-vivo training. Students’ knowledge of and ability to identify distress markers in preterm infants during bottle-feeding significantly improved after training in both groups without group differences

Training Clinical Judgment Skills for Interpreting Feeding Behavior in Preterm Infants: A Comparison of Video and In Vivo Simulation

Health and feeding outcomes for preterm infants depend upon healthcare providers’ ability to recognize non-verbal signs of distress during bottle-feeding. Methods of training future providers’ to interpret feeding behavior in preterm infants are unclear. This study used a pre-test/post-test design to compare the effects of in- vivo simulation and video-simulation training on students’ knowledge of feeding abnormalities, clinical judgment, and documentation accuracy. Fifty-two graduate level speech-language pathology students were assigned to the in-vivo (N= 27) or video-simulation (N= 25) group. Results revealed that both methods proved beneficial for increasing knowledge and clinical judgment skills. Participants trained using video-simulation training documented a greater number of distress signs. The use of patient simulators to train graduate level speech-language pathology students to use correct clinical judgment for managing abnormal feeding behavior is efficacious

生体と食塊の相互作用を考慮した嚥下シミュレーションに関する研究

学位の種別: 論文博士審査委員会委員 : （主査）東京大学教授 越塚 誠一, 東京大学教授 鈴木 克幸, 東京大学准教授 柴田 和也, 東京大学講師 近藤 雅裕, 武蔵野赤十字病院特殊歯科・口腔外科部長 道脇 幸博University of Tokyo(東京大学

Musculoskeletal Models in a Clinical Perspective

This book includes a selection of papers showing the potential of the dynamic modelling approach to treat problems related to the musculoskeletal system. The state-of-the-art is presented in a review article and in a perspective paper, and several examples of application in different clinical problems are provided