Purpose: Speech acoustic characteristics of children with cerebral palsy (CP) were examined with a multiple speech subsystems approach; speech intelligibility was evaluated using a prediction model in which acoustic measures were selected to represent three speech subsystems. Method: Nine acoustic variables reflecting different subsystems, and speech intelligibility, were measured in 22 children with CP. These children included 13 with a clinical diagnosis of dysarthria (speech motor impairment [SMI] group) and 9 judged to be free of dysarthria (no SMI [NSMI] group). Data from children with CP were compared to data from age-matched typically developing children. Results: Multiple acoustic variables reflecting the articulatory subsystem were different in the SMI group, compared to the NSMI and typically developing groups. A significant speech intelligibility prediction model was obtained with all variables entered into the model (adjusted R ² = .801). The articulatory subsystem showed the most substantial independent contribution (58%) to speech intelligibility. Incremental R ² analyses revealed that any single variable explained less than 9% of speech intelligibility variability. Conclusions: Children in the SMI group had articulatory subsystem problems as indexed by acoustic measures. As in the adult literature, the articulatory subsystem makes the primary contribution to speech intelligibility variance in dysarthria, with minimal or no contribution from other systems.

This study examined the relationship (1) between acoustic vowel space and the corresponding tongue kinematic vowel space and (2) between formant frequencies (F1 and F2) and tongue x-y coordinates for the same time sampling point. Thirteen healthy female adults participated in this study. Electromagnetic articulography and synchronized acoustic recordings were utilized to obtain vowel acoustic and tongue kinematic data across ten speech tasks. Intra-speaker analyses showed that for 10 of the 13 speakers the acoustic vowel space was moderately to highly correlated with tongue kinematic vowel space; much weaker correlations were obtained for inter-speaker analyses. Correlations of individual formants with tongue positions showed that F1 varied strongly with tongue position variations in the y dimension, whereas F2 was correlated in equal magnitude with variations in the x and y positions. For within-speaker analyses, the size of the acoustic vowel space is likely to provide a reasonable inference of size of the tongue working space for most speakers; unfortunately there is no a priori, obvious way to identify the speakers for whom the covariation is not significant. A second conclusion is that F1 variations reflect tongue height, but F2 is a much more complex reflection of tongue variation in both dimensions.

Purpose: The purpose is to investigate acoustic and tongue body kinematic vowel dispersion patterns and vowel space in speakers with and without dysarthria secondary to amyotrophic lateral sclerosis (ALS). Method: Acoustic and tongue kinematic vowel spaces were examined at the same time sampling point using electromagnetic articulography in 11 speakers with dysarthria secondary to ALS and 11 speakers without dysarthria. Tongue kinematic data were collected from the tongue body sensor (∼25 mm posterior from the tongue apex). A number of acoustic and tongue body kinematic variables were tested. Result: The result showed that the acoustic and tongue kinematic vowel dispersion patterns are different between the groups. Acoustic and tongue body kinematic vowel spaces are highly correlated; however, unlike acoustic vowel space, tongue body kinematic vowel space was not significantly different between the groups. Conclusion: Both acoustic and tongue kinematic vowel dispersion patterns are sensitive to the group difference, especially with high vowels. The tongue kinematic vowel space approach is too crude to differentiate the speakers with dysarthria secondary to ALS from speakers without dysarthria. To examine tongue range of motion in speakers with dysarthria, a more refined articulatory kinematic approach needs to be examined in the future.

Purpose The current study investigated whether articulatory kinematic patterns can be extrapolated across the spectrum of dysarthria severity in individuals with amyotrophic lateral sclerosis (ALS). Method Temporal and spatial articulatory kinematic data were collected using electromagnetic articulography from 14 individuals with dysarthria secondary to ALS and 6 typically aging speakers. Speech intelligibility and speaking rate were used as indices of severity. Results Temporal measures (duration, speed of articulators) were significantly correlated with both indices of severity. In speakers with dysarthria, spatial measures were not correlated with severity except in 3 measures: tongue movement displacement was more reduced in the anterior–posterior dimension; jaw movement distance was greater in the inferior–superior dimension; jaw convex hull area was larger in speakers with slower speaking rates. Visual inspection of movement trajectories revealed that overall spatial kinematic characteristics in speakers with severe dysarthria differed qualitatively from those in speakers with mild or moderate dysarthria. Unlike speakers with dysarthria, typically aging speakers displayed variable tongue movement and minimal jaw movement. Conclusions The current study revealed that spatial articulatory characteristics, unlike temporal characteristics, showed a complicated pattern across the severity spectrum. The findings suggest that articulatory characteristics in speakers with severe dysarthria cannot simply be extrapolated from those in speakers with mild-to-moderate dysarthria secondary to ALS.

Purpose The purpose of the study was to investigate vowel-specific intelligibility and acoustic patterns of individuals with different severities of dysarthria secondary to amyotrophic lateral sclerosis (ALS). Method Twenty-three individuals with dysarthria secondary to ALS and 22 typically aging individuals participated as speakers. Participants with ALS were divided into 2 severity groups (severe, mild). For vowel-specific intelligibility data, 135 listeners participated in the study. Vowel-specific intelligibility, intrinsic vowel duration, 1st and 2nd formants (F1 and F2), vowel inherent spectral change (VISC), and absolute VISC were examined. Results A significant interaction between severity group and the vowel-specific intelligibility pattern as well as F1, F2 VISC, and absolute F2 VISC was observed. Specifically, individuals with severe dysarthria showed a significantly less intelligible /ɪ/ than /ɛ/, unlike individuals with mild dysarthria and typically aging individuals. In addition, vowel intel...