The Distributed Lambda (λ) Model (DLM): A 3-D, Finite-Element Muscle Model Based on Feldman's λ Model; Assessment of Orofacial Gestures PurposeThe authors aimed to design a distributed lambda model (DLM), which is well adapted to implement three-dimensional (3-D), finite-element descriptions of muscles.MethodA muscle element model was designed. Its stress–strain relationships included the active force–length characteristics of the λ model along the muscle fibers, together with the passive properties of muscle ... Research Article
Research Article  |   December 01, 2013
The Distributed Lambda (λ) Model (DLM): A 3-D, Finite-Element Muscle Model Based on Feldman's λ Model; Assessment of Orofacial Gestures
 
Author Affiliations & Notes
  • Mohammad Ali Nazari
    GIPSA-lab, CNRS UMR 5216, University of Grenoble Alpes, Grenoble, France
  • Pascal Perrier
    GIPSA-lab, CNRS UMR 5216, University of Grenoble Alpes, Grenoble, France
  • Yohan Payan
    GIPSA-lab, CNRS UMR 5216, University of Grenoble Alpes, Grenoble, France
  • Disclosure:The authors have declared that no competing interests existed at the time of publication.
    Disclosure:The authors have declared that no competing interests existed at the time of publication.×
  • Correspondence to Mohammad Ali Nazari: Mohammad.Nazari@gipsa-lab.grenoble-inp.fr
  • Editor: Jody Kreiman
    Editor: Jody Kreiman×
  • Associate Editor: Lucie Ménard
    Associate Editor: Lucie Ménard×
Article Information
Speech, Voice & Prosody / Supplement
Research Article   |   December 01, 2013
The Distributed Lambda (λ) Model (DLM): A 3-D, Finite-Element Muscle Model Based on Feldman's λ Model; Assessment of Orofacial Gestures
Journal of Speech, Language, and Hearing Research, December 2013, Vol. 56, S1909-S1923. doi:10.1044/1092-4388(2013/12-0222)
History: Received July 10, 2012 , Revised February 23, 2013 , Accepted June 12, 2013
 
Journal of Speech, Language, and Hearing Research, December 2013, Vol. 56, S1909-S1923. doi:10.1044/1092-4388(2013/12-0222)
History: Received July 10, 2012; Revised February 23, 2013; Accepted June 12, 2013
Web of Science® Times Cited: 1

PurposeThe authors aimed to design a distributed lambda model (DLM), which is well adapted to implement three-dimensional (3-D), finite-element descriptions of muscles.

MethodA muscle element model was designed. Its stress–strain relationships included the active force–length characteristics of the λ model along the muscle fibers, together with the passive properties of muscle tissues in the 3-D space. The muscle element was first assessed using simple geometrical representations of muscles in the form of rectangular bars. It was then included in a 3-D face model, and its impact on lip protrusion was compared with the impact of a Hill-type muscle model.

ResultsThe force–length characteristic associated with the muscle elements matched well with the invariant characteristics of the λ model. The impact of the passive properties was assessed. Isometric force variation and isotonic displacements were modeled. The comparison with a Hill-type model revealed strong similarities in terms of global stress and strain.

ConclusionThe DLM accounted for the characteristics of the λ model. Biomechanically, no clear differences were found between the DLM and a Hill-type model. Accurate evaluations of the λ model, based on the comparison between data and simulations, are now possible with 3-D biomechanical descriptions of the speech articulators because of the DLM.

Acknowledgments
This work was partly funded by the French Agence Nationale de la Recherche (Project ANR-08-Blan-0272-01) and by the French German University (Project DFH/UFA G2R-FA-16-07). We address special thanks to Matthieu Chabanas from Gipsa-lab for fruitful discussions at early stages of the project.
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