A cineradiographic and electromyographic investigation of velar positioning in non-nasal speech.

Simultaneous cineradiographic and electromyographic analyses were made of the speech of three male and three female normal speaking adults. Each subject produced a series of symmetrical non-nasal CVC syllables embedded in a carrier phrase in a normal manner and also at increased rate and effort levels. A model of velar control was formulated and tested in relationship to changes in velar height resulting from forces provided by tongue positioning and contraction of levator veli palatini, palatoglossus, and palatopharyngeus muscles. Two patterns of levator activity were observed in the six subjects. Palatopharyngeus activity appeared to be important in producing adjustments in exact velar position when the velum was in a elevated state. Palatoglossus activity appeared to be related to elevation of the posterior portion of the tongue. The time differences between changes in muscle activity and velar positioning were determined. The results provide additional normative data regarding velar activity and serve to illustrate the need to view the velum as a complex mechanical system.