A Technique for Recording Velar Movement

Abstract

Soft palate or velar movement during speech has been studied using a variety of observational techniques. Lubker and Moll (6') have divided these methods of observation into two general categories, indirect and direct techniques. These authors point out that indirect methods, such as quantitative measurement of oral and nasal air pressures and flows, yield inferences about articulatory and physiological activities such as velar movement during speech. Direct techniques such as radiographic methods enable investigators to make direct quantitative measurements of the articulatory mechanism during speech. Both methods provide a considerable amount of knowledge concerning velopharyngeal function in general and velar movement in particular during normal and pathological speech. However, if one is concerned with obtaining a quantitative continuous measure of velar movement instantaneously during speech for prolonged periods of time, then the traditional methods mentioned above have cer— tain disadvantages. The indirect techniques infer velar movement as part of the more complex phenomenon of velopharyngeal closure. Radiographic techniques, such as cineradiography, provide quantitative information of velar movement, but this information is not immediately available during speech production. In addition to the lack of an instantaneous readout of velar movement during speech production, several investigators (Chase, 1; Moll, 8; Fletcher et al., 4; Lubker and Moll, 6; Lubker and Morris, '7) have noted certain inherent concerns in the use of radiographic techniques. These concerns include quality and limited field of view of projection, laborious measurement procedures, expense and radiation exposure. The present study involves the development of a new technique for recording velar movements during speech (2, 3). Basically, the technique employs resistance strain gage displacement transducers. Strain gage transducers are relatively simple in design and function, are relatively inexpensive to use, eliminate exposure hazard, provide for continuous and instantaneous recording of velar movement during speech production, and allow for observation of velar movement over extended periods of time. The specific purposes of the study, in addition to the development of instrumentation for recording velar movement during speech were: 1) to 263