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Rate-dependent articulatory performance changes in talkers with amyotrophic lateral sclerosis

Antje S Mefferd, University of Nebraska - Lincoln


Three studies were conducted to identify articulatory movement constraints during the early stages of ALS when speech intelligibility and speaking rate are minimally affected. A secondary goal was to identify compensatory behaviors in response to these putative physiological constraints. ^ Eight individuals with ALS and eight age and gender matched healthy controls participated in this study. Lower lip and jaw movements were recorded using a 3-dimensional optical motion analysis system. In the first study, the ability to increase lip and jaw speed was tested using a novel fixed-target task. Talkers with ALS showed a limited ability to generate the speeds necessary to reach the fixed target in a timely manner even at the early stages of the disease. Constraints in articulatory movement speed were not detected during an unconstrained speaking task. ^ In the second study, the relative contribution of the jaw was compared between talkers with ALS and controls to identify potential constraints in articulatory movement strategies used to increase speaking rate. The relative contribution of the jaw was greater in talkers with ALS than in healthy controls. In addition, talkers with ALS exhibited minimal rate-related changes in the relative contribution of the jaw during sentence repetitions, which was suggestive of limited coordinative flexibility. ^ In the third study, the spatiotemporal variability of the lower lip was measured during sentence repetitions at various speaking rates and during loud speech to identify a potential limited ability to produce consistent movement patterns. In contrast to this hypothesis, talkers with ALS produced lower lip movements with lower spatiotemporal variability during typical and slower speech rates, but displayed higher movement variability than healthy controls during loud speech. ^ Although the functional significance of these constraints is not fully understood, they may explain some well-know speech phenomena in ALS (i.e., decline in speaking rate and intelligibility). Further, results point to the potential diagnostic and prognostic value of kinematic measures for determining the onset and rate of disease progression of bulbar deterioration due to ALS.^

Subject Area

Biology, Neuroscience|Health Sciences, Speech Pathology

Recommended Citation

Mefferd, Antje S, "Rate-dependent articulatory performance changes in talkers with amyotrophic lateral sclerosis" (2008). ETD collection for University of Nebraska - Lincoln. AAI3331437.