Digital, labial, and velopharyngeal reaction times in normal speakers

The relationship between inherent speed limitations of the velopharyngeal mechanism and the observed phenomenon of assimilation nasality was investigated by studying the reaction times of 10 normal adults performing three movements: (1) lip closing, (2) velopharyngeal closing, and (3) pressing a response key with a finger. The first two movements were monitored using a photodetector system. Across nearly 300 responses for each of the motor responses, the average reaction times, in milliseconds, were 194 for the digital, 203 for the labial, and 206 for the velopharyngeal movements. An analysis of variance revealed no consistent differences among these responses. The significance of these data is discussed with respect to speech motor control and clinical evaluation of patients with velopharyngeal impairments.