A Preliminary Investigation of Velopharyngeal Timing in Normally Developing Preschool Children and Those with Speech Sound Disorders

Abstract

As children acquire speech and language, they also begin to develop speech motor control. A widely accepted theoretical model for explaining speech acquisition and motor modifications necessary for appropriate speech is the Directions Into Velocities of Articulators (DIVA) model. This model posits that individuals plan and produce speech (feedforward system). If errors in speech are identified, they are modified since the DIVA Model includes a feedback system that is sensitive to such perturbations made during speech production (feedback system). This feedback system functions to make positive changes to one's motor programming for speech. Literature suggests that children gain stability of articulators as they mature, but children with speech sound disorders (SSDs) achieve stability of articulators, e.g. jaw and lips, at a later age than their typically developing peers which may suggest a breakdown in their feedforward system. However, to our knowledge, no previous studies have analyzed velopharyngeal timing differences in children with SSDs in comparison to their typically developing peers. There is some limited evidence that suggests children with language delays present with delays in velopharyngeal development, which caused the researchers of the study to question the possibility of velopharyngeal timing differences in children with SSDs of unknown etiology. The findings of the current study indicate more variability in velopharyngeal timing for children with SSDs; however, comparison with children who had typically developing speech did not always show statistically significant differences. The trend of variability in velopharyngeal timing that was identified should be further examined with larger subject groups.