A finite element method (FEM) based numerical model of upper airway structures (jaw, tongue, maxilla, soft palate) was implemented to observe interactions between the soft palate and tongue, and in particular to distinguish the contributions of individual muscles in producing speech-relevant constrictions of the oropharyngeal isthmus (OPI), or “uvular” region of the oral tract. Simulations revealed a sphincter-like general operation for the OPI, particularly with regard to the function of the palatoglossus muscle. Further, as has been observed with the lips, the OPI can be controlled by multiple distinct muscular mechanisms, each reliably producing a different sized opening and robust to activation noise, suggestive of a modular view of speech motor control. As off-midline structures of the OPI are difficult to observe during speech production, biomechanical simulation offers a promising approach to studying these structures.
A three-dimensional (3D) computer simulation of swallowing is presented. The soft structures (i.e. pharyngeal wall, soft palate and tongue) are simulated using finite element models. Bony structures (e.g. mandible, hard palate and hyoid) are simulated as rigid bodies. A fluid bolus is simulated using smoothed particle hydrodynamics (SPH). A Newtonian viscosity model is validated by comparing a 3D SPH simulation of Hagen -Poiseuille flow with theoretical results. A previously unreported source of error is reported and discussed. In the swallowing simulation, fluid boundaries are determined by the rigid and deformable surfaces, and the coupling is in one direction only. Movement of solid boundaries was determined in previous work for a deformable solid bolus. Two swallowing simulations are presented with different bolus viscosities in order to demonstrate that SPH can be used to simulate and track the liquid phase of a bolus during swallow. We find that SPH robustly handles moving boundary conditions as well as changes in viscosity. SPH simulations of the bolus are therefore potentially a useful visual aid to understand the effects of solid boundary motion on swallowing.
The same procedure was used to build up a generic reference model of the dentition, tongue, mandible and airway from a mixture of medical records (CT and dental casts) of the same subject. This manual segmentation method eliminated the common errors that occur from an automatic segmentation although it was more time-consuming. It remains a fundamental process for analyzing the dynamic interaction between anatomical components in the oral, pharyngeal, and laryngeal areas.
Abstract. The DreamThrower is a novel technology that explores virtually creating, throwing and catching dreams. It detects users' dream state by measuring rapid eye movement (REM). Once the dream state is detected, sound and light stimuli is played to alter the dream. Users report on their dream, and they can send the stimuli that they have used to another person via an on-line website. A working prototype accurately detects REM sleep. Based on preliminary results, the sound and light stimuli were found to have little influence on their dreams. Our prototype's ability to detect REM effectively coupled to a social network to share dream stimuli opens up a fun game environment even if the stimuli itself does not have a significant impact. Instead, user engagement with the social network may be sufficient to alter dreams. Further studies are needed to determine whether stimulus during REM can be created to alter dreams significantly.
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