Variability of jaw movement in contrastive stress production of children with and without speech delay of unknown origin

Abstract

This study was designed to evaluate the control of jaw movement in contrastive stress productions of children with and without speech delay. The spatiotemporal index (STI) was used to calculate variability in jaw movement trajectories in 12 children producing three different metrical forms of CVCV syllables (trochaic, iambic, and even stress; papa, mama, and baba). The children (mean age: 3;2 years) were categorized, four in each of three groups, as having Normal Speech Acquisition (NSA), Speech Delay (SD), or both (NSA/SD) using the Speech Disorder Classification System (Shriberg et al., 1997). Results replicated findings in typically developing children of a similar age reported by Goffman and Malin (1999) where iambic forms were produced with greater stability than trochaic forms as measured by the STI. Analysis using a repeated measures ANOVA revealed significant effects for contrastive stress type, speech disorder classification, and syllable identity. Results are reported in the context of vowel acoustic measures of contrastive stress. [Work supported by NIDCD R01 DC 0000822-10.]