DEVELOPMENT AND APPLICATION OF A PRESSURE SENSING ELECTROPALATOGRAPH

Electropalatography (EPG) is a physiological, instrumental technique, which has been shown to be valuable in the assessment and treatment of a wide range of speech disorders. The EPG technique involves the use of an artificial acrylic palate, which contains an array of touch-sensitive electrodes that detect the location and timing of tongue contacts against the roof of the mouth (hard palate) during speech. Although the current EPG system provides valuable information regarding the spatial and timing aspects of tongue contacts during speech, it is limited in that it cannot provide information regarding the pressures with which the tongue contacts the palate. This paper reports on the development of a pressure sensitive EPG device. First, possible pressure sensing methodologies are discussed and compared, and the operation principle of the new, small area Hall-effect pressure transducer introduced. Second, the major design process stages are discussed: 1) position and orientation of transducer components, 2) sensitivity evaluation, 3) active pressure element design, and the final transducer configuration introduced. Third, the processes involved to manufacture individual transducer units are outlined, and the calibration results for individual sensor elements are shown. Finally, the construction of a first, pressure sensitive artificial EPG palate is outlined. The results show that Hall-effect pressure sensors are a technically viable, economical option for the construction of a pressure sensitive EPG system.