3aSC44. Acoustic correlates of segmentalized speech patterns in motor speech disorders.

Session: Wednesday Morning, December 4


Author: Kris Tjaden
Location: Dept. of Communicative Disord., San Diego State Univ., San Diego, CA 92182-1518


It has been argued that principles of gestural-based speech production theory may account for speech production aberrancies in motor speech disorders (MSDs) [Weismer et al., J. Phon. 23, 111--126 (1995)]. In the present study, four individuals with MSDs exhibiting segmentalized speech patterns (e.g., perceptual impression of speech being ``metered out'' segment by segment) and four controls produced CV words in carrier phrases at fast and habitual rates. Degree of gesture overlap was indexed by F2 onset frequency. Descriptive measures of F2 onset were used to evaluate whether segmentalized speech patterns in MSDs were associated with reduced gesture overlap in comparison to controls. Temporal variability in F2 formant trajectories for all speakers was modeled as the mutual sliding of adjacent gestures using regression analyses. Three disordered speakers showed evidence of reduced overlap for targets produced at habitual rates in comparison to controls; this difference generally was maintained at fast rates. For all speakers, fast rates were associated with reductions in both gesture magnitude and overlap relative to habitual rates. Regression analyses suggested that temporal variability in F2 trajectories of select targets produced at habitual rates may be modeled as the mutual sliding of gestures. Individual differences and stimuli effects are discussed.

ASA 132nd meeting - Hawaii, December 1996