Articulator-Specific Performance Changes and their Acoustic Consequences: Findings on Typical Talkers and Talkers with Dysarthria

Antje Mefferd, PhD CCC-SLP (Assistant Professor, Vanderbilt University Medical Center)

Although imprecise articulation is the hallmark of dysarthria, little is currently known about the articulator-specific mechanisms that underlie these imprecisions and how to best treat them. Speech behavioral interventions such as loud, slow, or clear speech cues are commonly used to improve the speech of talkers with dysarthria; however, the selection of one of these three treatments is often based on trial therapy rather than a scientific rationale.

Over the past few years, we have directed our research efforts towards an improved understanding of the articulator-specific mechanisms that underlie currently used therapeutic interventions. Therefore, I will report findings of a series of studies that examined tongue- and jaw-specific performance changes in response to loud, clear, and slow speech cues in typical talkers as well as talkers with Parkinson’s disease and amyotrophic lateral sclerosis (ALS). We recorded tongue and jaw articulatory movements using 3D electromagnetic articulography. In addition to cueing effects, I will report how cueing-related changes in tongue and jaw motor performance contributed to acoustic vowel contrast change in these talkers. Finally, I will share preliminary findings on a recent study that investigated articulatory tradeoffs between tongue retraction and lip protrusion and their consequences for acoustic vowel contrast in talkers with ALS. The overarching goal of our work is to provide a scientific basis for clinical decisions on speech treatment selection for talkers with dysarthria.