COORDINATION OF VELOPHARYNGEAL MUSCLE-ACTIVITY DURING POSITIONING OF THE SOFT PALATE

The relative contributions of the levator veli palatini, palatoglossus , and palatopharyngeus muscles were assessed relative to a range of po sitions of the velopharynx during production of the vowels [a] and [i] by four normal adult speakers. The results indicate that velopharynge al positioning is determined by the relative contributions of the leva tor veli palatini, palatoglossus, and palatopharyngeus muscles. There was an increase in coefficients of determination (i.e., amount of clos ure level variability explained) when activity levels of all three mus cles are included in the statistical model compared to activity in any one muscle analyzed independently. Both consistent and inconsistent r elations among activity levels in the three velopharyngeal muscles stu died were observed across speaker and vowel produced.