Abstract
Evaluation of tongue movements is often hampered by the morphological complexityof the tongue. We analyzed tongue movements wtih an optical sensing system developed by the Department of Electrical Engineering and Computer Science, Faculty of Engineering, Kumamoto University, in which micro photo-transistors were incorporated.
The distance between the palate and the surface of the tongue was measured by photometry of the reflex light. The palatal plate employed for the measurement had a phototransistor and a sensor consisting of two LED's placed asymmetrically relative to the phototransistor and driven at a 90° phase shift. The sensor-tongue distance was determined as a function of the phase angle of reflex light signals, which provided distance-sensing characteristics less susceptible to the effects of the reflection factor than the methods based on the amplitude. The available output range was to 30 mm toward the lower surface of the tongue from the sensor placed on the hard palate. From these results, the apparatus was considered to be useful for evaluation of tongue movements.
