Variability of oronasal coupling in children and adults

Abstract

Oronasal coupling in young children remains poorly understood primarily because of experimental challenges associated with non-invasive techniques for transducing velopharyngeal movement. Productions of the word [bama] were studied in children with normal speech acquisition (NSA) and children with speech delay (SD; 3-to-5 years of age) with respect to adults. Nasal vibration was transduced using a small, lightweight accelerometer affixed to the lateral alar cartilage of the participant’s nose. The variability in the nasal acceleration signals obtained for multiple productions of the stimuli for each participant was described using the spatiotemporal index (STI) and functional data analysis (FDA). The spatiotemporal index served as a composite method of variability following linear time normalization of the signals. The FDA technique involving nonlinear time normalization allowed for independent evaluation of amplitude and phase variability. The two groups of children with NSA and SD were more variable than the adults on both measures of STI and amplitude variability, while the amount of phase variability was similar between children and adults. These methods have complementary merits and potential in revealing the properties of development and disruption of oronasal coupling in children and adults. [Work supported by NIH-NIDCD.]