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A computational neuromuscular model of the human upper airway with application to the study of obstructive sleep apnoea

by jppelteret

Author: J-P. V. Pelteret

Numerous challenges are faced in investigations aimed at developing a better understanding of the pathophysiology of obstructive sleep apnoea. The anatomy of the tongue and other upper airway tissues, and the ability to model their behaviour, is central to such investigations.

In this thesis, details of the construction and development of a three-dimensional finite element model of soft tissues of the human upper airway, as well as a simplified fluid model of the airway, are provided. The anatomical data was obtained from the Visible Human Project, and its underlying micro-histological data describing tongue musculature were also extracted from the same source and incorporated into the model. An overview of the mathematical models used to describe tissue behaviour, both at a macro- and microscopic level, is given. Hyperelastic constitutive models were used to describe the material behaviour, and material incompressibility was accounted for. An active Hill three-element muscle model was used to represent the muscular tissue of the tongue. The neural stimulus for each muscle group to a priori unknown external forces was determined through the use of a genetic algorithm-based neural control model.

The fundamental behaviour of the tongue under gravitational and breathing-induced loading is investigated. The response of the various muscles of the tongue to the complex loading developed during breathing is determined, with a particular focus being placed to that of the genioglossus. It is demonstrated that, when a time-dependent loading is applied to the tongue, the neural model is able to control the position of the tongue and produce a physiologically realistic response for the genioglossus. A comparison is then made to the response determined under quasi-static conditions using the pressure distribution extracted from computational fluid-dynamics results. An analytical model describing the time-dependent response of the components of the tongue musculature most active during oral breathing is developed and validated. It is then modified to simulate the activity of the tongue during sleep and under conditions relating to various possible neural and physiological pathologies. The retroglossal movement of the tongue resulting from the pathologies is quantified and their role in the potential to induce airway collapse is discussed. [1]

[1] [pdf] J-P. V. Pelteret, “A computational neuromuscular model of the human upper airway with application to the study of obstructive sleep apnoea,” Engineering PhD Thesis, Rondebosch, Western Cape, South Africa, 2013.
[Bibtex]
@PhdThesis{pelteret2013b-phd_thesis,
author = {Pelteret, J-P. V.},
title = {A computational neuromuscular model of the human upper airway with application to the study of obstructive sleep apnoea},
school = {University of Cape Town},
year = {2013},
type = {Engineering},
address = {Rondebosch, Western Cape, South Africa},
month = {November},
abstract = {Numerous challenges are faced in investigations aimed at developing a better understanding of the pathophysiology of obstructive sleep apnoea. The anatomy of the tongue and other upper airway tissues, and the ability to model their behaviour, is central to such investigations.
In this thesis, details of the construction and development of a three-dimensional finite element model of soft tissues of the human upper airway, as well as a simplified fluid model of the airway, are provided. The anatomical data was obtained from the Visible Human Project, and its underlying micro-histological data describing tongue musculature were also extracted from the same source and incorporated into the model. An overview of the mathematical models used to describe tissue behaviour, both at a macro- and microscopic level, is given. Hyperelastic constitutive models were used to describe the material behaviour, and material incompressibility was accounted for. An active Hill three-element muscle model was used to represent the muscular tissue of the tongue. The neural stimulus for each muscle group to a priori unknown external forces was determined through the use of a genetic algorithm-based neural control model.
The fundamental behaviour of the tongue under gravitational and breathing-induced loading is investigated. The response of the various muscles of the tongue to the complex loading developed during breathing is determined, with a particular focus being placed to that of the genioglossus. It is demonstrated that, when a time-dependent loading is applied to the tongue, the neural model is able to control the position of the tongue and produce a physiologically realistic response for the genioglossus. A comparison is then made to the response determined under quasi-static conditions using the pressure distribution extracted from computational fluid-dynamics results. An analytical model describing the time-dependent response of the components of the tongue musculature most active during oral breathing is developed and validated. It is then modified to simulate the activity of the tongue during sleep and under conditions relating to various possible neural and physiological pathologies. The retroglossal movement of the tongue resulting from the pathologies is quantified and their role in the potential to induce airway collapse is discussed.},
file = {pelteret2013b-phd_thesis.pdf:PDF/pelteret2013b-phd_thesis.pdf:PDF},
keywords = {sleep-disordered breathing; obstructive sleep apnoea; tongue; human upper airway; computational model; skeletal muscle model; Hill three-element model; neural control model; genetic algorithm; finite element method},
owner = {Jean-Paul Pelteret},
timestamp = {2015.10.11},
url = {http://hdl.handle.net/11427/9519},
}

Development of a computational biomechanical model of the human upper-airway soft-tissues towards simulating obstructive sleep apnea

by jppelteret

Authors: J-P. V. Pelteret, and B. D. Reddy

Numerous challenges are faced in investigations aimed at developing a better understanding of the pathophysiology of obstructive sleep apnea (OSA). The anatomy of the tongue and other upper-airway tissues, and the ability to model their behavior, are central to such investigations. We present details of the construction and development of a soft-tissue model of the human upper airway, with the ultimate goal of simulating obstructive sleep apnea. The steps taken to produce a representative anatomical geometry, of which the associated muscle histology is also captured, are documented. An overview of the mathematical models used to describe tissue behavior, both at a macro- and microscopic level, is given. A neurological model, which mimics the proprioceptive capabilities of the body, is described as it is applies to control of the active dynamics of the tongue. A simplified scenario, which allows for the manipulation of several environmental influences, is presented. It is demonstrated that the response of the genioglossus is qualitatively similar to that determined through experimental techniques. Furthermore, insights into the stress distribution developed within the tongue are discussed. It is shown that changes in almost any aspect of the breathing or physiological conditions invoke a significant change in the response of the airway dilators. The results of this study provide further evidence of the importance of modeling and simulation techniques as an aid in understanding the complex behavior of the human body. [1]

[1] [pdf] [doi] J-P. V. Pelteret and B. D. Reddy, “Development of a computational biomechanical model of the human upper–airway soft–tissues towards simulating obstructive sleep apnea,” Clinical Anatomy, vol. 27, iss. 2, pp. 182-200, 2013.
[Bibtex]
@Article{pelteret2013a-preprint,
author = {Pelteret, J-P. V. and Reddy, B. D.},
title = {Development of a computational biomechanical model of the human upper--airway soft--tissues towards simulating obstructive sleep apnea},
journal = {Clinical Anatomy},
year = {2013},
volume = {27},
number = {2},
pages = {182--200},
abstract = {Numerous challenges are faced in investigations aimed at developing a better understanding of the pathophysiology of obstructive sleep apnea (OSA). The anatomy of the tongue and other upper-airway tissues, and the ability to model their behavior, are central to such investigations. We present details of the construction and development of a soft-tissue model of the human upper airway, with the ultimate goal of simulating obstructive sleep apnea. The steps taken to produce a representative anatomical geometry, of which the associated muscle histology is also captured, are documented. An overview of the mathematical models used to describe tissue behavior, both at a macro- and microscopic level, is given. A neurological model, which mimics the proprioceptive capabilities of the body, is described as it is applies to control of the active dynamics of the tongue. A simplified scenario, which allows for the manipulation of several environmental influences, is presented. It is demonstrated that the response of the genioglossus is qualitatively similar to that determined through experimental techniques. Furthermore, insights into the stress distribution developed within the tongue are discussed. It is shown that changes in almost any aspect of the breathing or physiological conditions invoke a significant change in the response of the airway dilators. The results of this study provide further evidence of the importance of modeling and simulation techniques as an aid in understanding the complex behavior of the human body.},
doi = {10.1002/ca.22313},
file = {pelteret2013a-preprint.pdf:PDF/pelteret2013a-preprint.pdf:PDF},
keywords = {obstructive sleep apnea; tongue; human upper-airway; computational model; skeletal muscle model; neural model; finite-element method},
owner = {Jean-Paul Pelteret},
timestamp = {2015.10.11},
}

Computational model of soft tissues in the human upper airway

by jppelteret

Authors: J-P. V. Pelteret, and B. D. Reddy

This paper presents a three-dimensional finite element model of the tongue and surrounding soft tissues with potential application to the study of sleep apnoea and of linguistics and speech therapy. The anatomical data was obtained from the Visible Human Project, and the underlying histological data was also extracted and incorporated into the model. Hyperelastic constitutive models were used to describe the material behaviour, and material incompressibility was accounted for. An active Hill three-element muscle model was used to represent the muscular tissue of the tongue. The neural stimulus for each muscle group was determined through the use of a genetic algorithm-based neural control model. The fundamental behaviour of the tongue under gravitational and breathing-induced loading is investigated. It is demonstrated that, when a time-dependent loading is applied to the tongue, the neural model is able to control the position of the tongue and produce a physiologically realistic response for the genioglossus. [1]

[1] [pdf] [doi] J-P. V. Pelteret and B. D. Reddy, “Computational model of soft tissues in the human upper airway,” International Journal for Numerical Methods in Biomedical Engineering, vol. 28, iss. 1, pp. 111-132, 2012.
[Bibtex]
@Article{pelteret2012a-preprint,
author = {Pelteret, J-P. V. and Reddy, B. D.},
title = {Computational model of soft tissues in the human upper airway},
journal = {International Journal for Numerical Methods in Biomedical Engineering},
year = {2012},
volume = {28},
number = {1},
pages = {111--132},
month = {January},
abstract = {This paper presents a three-dimensional finite element model of the tongue and surrounding soft tissues with potential application to the study of sleep apnoea and of linguistics and speech therapy. The anatomical data was obtained from the Visible Human Project, and the underlying histological data was also extracted and incorporated into the model. Hyperelastic constitutive models were used to describe the material behaviour, and material incompressibility was accounted for. An active Hill three-element muscle model was used to represent the muscular tissue of the tongue. The neural stimulus for each muscle group was determined through the use of a genetic algorithm-based neural control model. The fundamental behaviour of the tongue under gravitational and breathing-induced loading is investigated. It is demonstrated that, when a time-dependent loading is applied to the tongue, the neural model is able to control the position of the tongue and produce a physiologically realistic response for the genioglossus.},
doi = {10.1002/cnm.1487},
file = {pelteret2012a-preprint.pdf:PDF/pelteret2012a-preprint.pdf:PDF},
keywords = {human upper airway; tongue; muscle model; neural control model; genetic algorithm; finite element method},
owner = {Jean-Paul Pelteret},
timestamp = {2015.10.11},
}