14 research outputs found
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Analysis of the symmetry of electrodes for Electropalatography with Cone Beam CT Scanning
The process of compression of air and vibration of activity in the larynx through which speech is produced is of great interest in phonetics, phonology, psychology and is related to various areas of biomedical engineering as it has a strong relationship with cochlear implants, Parkinsonâs disease and Stroke. One technique by means of which speech production is analysed is the use of electropalatography, in which an artificial palate, moulded to the speakersâ hard palate is introduced in the mouth. The palate contains a series of electrodes, which monitor contact between the tongue and the palate during speech production. There is interest in the symmetry or asymmetry of the movement of the tongue as this may be related to languages or right- or left-handedness, however this has never been thoroughly studied. A specific limitation of electropalatography for symmetry studies is that palates are hand-crafted and the position of the electrodes themselves may be asymmetric. In this work, we analyse the positioning of electrodes of one electropalatography setting. The symmetry was analysed by locating the electrodes of the palate through the observation of the palate with Computed Tomography. An algorithm to segment the electrodes and find the symmetry of left and right sides of the palates is described. No significant asymmetry was found for one specific palate. The methodology presented should allow the analysis of palates to be used in larger studies of speech production
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Visualisation and Analysis of Speech Production with Electropalatography
The process of speech production, i.e., the compression of air in the lungs, the vibration activity of the larynx, and the movement of the articulators, is of great interest in phonetics, phonology, and psychology. One technique by which speech production is analysed is electropalatography, in which an artificial palate, moulded to the speakerâs hard palate, is introduced in the mouth. The palate contains a grid of electrodes, which monitor the spatial and temporal pattern of contact between the tongue and the palate during speech production. The output is a time sequence of images, known as palatograms, which show the 2D distribution of electrode activation. This paper describes a series of tools for the visualisation and analysis of palatograms and their associated sound signals. The tools are developed as MatlabÂŽ routines and released as an open-source toolbox. The particular focus is the analysis of the amount and direction of leftâright asymmetry in tongueâpalate contact during the production of different speech sounds. Asymmetry in the articulation of speech, as measured by electropalatography, may be related to the language under consideration, the speakerâs anatomy, irregularities in the palate manufacture, or speaker handedness (i.e., left or right). In addition, a pipeline for the segmentation and analysis of a three-dimensional computed tomography data set of an artificial palate is described and demonstrated. The segmentation procedure provides quantitative information about asymmetry that is due to a combination of speaker anatomy (the shape of the hard palate) and the positioning of the electrodes during manufacture of the artificial palate. The tools provided here should be useful in future studies of electropalatography
Tongue-Palate Interaction in Discrete and Sequential Swallowing
Historically, swallowing motor control was thought to involve a central mechanism that generated patterned responses with little use of sensory input. Although increasing evidence of peripheral modulation has altered this concept, our knowledge about the flexibility in deglutitive motor control and performance is incomplete. This study sought to gain a better understanding by examining lingual motor strategies in light of changing bolus properties (volume, consistency) and task demands (discrete vs. sequential swallowing). Specifically, the timing and patterns of tongue-palate contact and the associated changes in tongue shape and action were examined in five normal adults using simultaneous electropalatography (EPG) and ultrasound. Tasks for discrete swallowing included 5 and 30 cc of water, 5 and 30 cc of gelatin, and saliva. Tasks for sequential swallowing involved drinking 200 cc of water at normal and fast rates. Two analysis schemes were used to make timing and percent-contact measurements: segmentation of the EPG time series into four stages (prepropulsion, propulsion, full contact, withdrawal), and compartmentalization of the pseudopalate into six bins (front, central, back, lateral, medial, midline). Results showed little variation in contact pattern as a function of bolus property or subject, suggesting considerable stereotypy in lingual motor strategies for movement sequencing. However, unlike the conventional description, tongue-palate contact during propulsion was multidimensional with two distinct degrees of freedom in the front-to-back and the lateral-to-midline continua. Significant (Q<. 0 I) timing differences were found in that larger and thinner boluses were propelled faster than smaller and thicker ones, and dry swallows had longer full contact than water. For sequential swallowing during continuous drinking, the tongue used faster movement speed and overlapping gestures to meet the task demands, while propulsive contact pattern remained invariant. Thus, the change was not in motor strategies per se but in the timing coordination of the "drink" and "swallow" sequences. A 3-D model of oral lingual action for swallowing was proposed. Clinical implications were discussed. In sum, results of this study support the theory that swallowing motor control includes a peripheral mechanism capable of modulating centrally generated responses, and that the deglutitive motor program has both invariant and variant parameters