O043 Investigating Upper-Airway Mechanics with Computational Tongue Models

With the use of computational models of the oral cavity, we aim to understand how changes in the morphology of the oral cavity and changes the stiffness of the tongue affect the movement of the posterior surface of the tongue. Anatomical and diffusion weighted imaging from 20 healthy individuals (10M:10F, Age: 22-54years, BMI: 17-30kg/m²), were used to develop 3D models of the tongue including the fibre orientations of the tongue muscles. All models were aligned and scaled to match the volume of the average subject's mandible, so that only differences in shape were modelled. The muscles of the tongue were modelled as transversely isotropic, with a shear moduli of 2.9 and 1.0kPa, parallel and perpendicular to the muscle fibre direction, respectively. Each individual participant model was prescribed an active contraction producing 50kPa of stress in the horizontal component of the genioglossus. The influence of initial hyoid position on the average anterior displacement of the posterior surface of the tongue was assessed with linear regression. On average the contraction moved the posterior tongue 4.0±0.7mm anteriorly. For every millimetre of hyoid elevation, anterior tongue displacement (i.e. airway dilation) decreased by 0.1mm. These initial models demonstrate that the automated modelling pipeline can identify how structural differences alter the efficacy of dilator muscles. Future implementations of these models will also incorporate experimentally measured pharyngeal pressures, and temporal and spatial patterns of muscle activations based on experimental data, to assess the how variation in the coordinated contractions contributes to airway collapse.