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Purpose: Hypernasality and atypical voice characteristics are common features of dysarthric speech due to amyotrophic lateral sclerosis (ALS). Existing acoustic measures have been developed to primarily target either hypernasality or voice impairment, and the effects of co-occurring hypernasality-voice problems on these measures are unknown. This report explores (a) the extent to which acoustic measures are affected by concurrent perceptually identified hypernasality and voice impairment due to ALS and (b) candidate acoustic measures of early indicators of hypernasality and voice impairment in the presence of multisystem involvement in individuals with ALS. Method: Two expert listeners rated severity of hypernasality and voice impairment in sentences produced by individuals with ALS (n = 27). The samples were stratified based on perceptual ratings: voice/hypernasality asymptomatic, predominantly hypernasal, predominantly voice impairment, and mixed (co-occurring hypernasality and voice impairment). Groups were compared using established acoustic measures of hypernasality (one-third octave analysis) and voice (cepstral/spectral analysis) impairment. Results: The one-third octave analysis differentiated all groups; the cepstral peak prominence differentiated all groups except asymptomatic versus mixed, whereas the low-to-high spectral ratio did not differ among groups. Additionally, one-third octave analyses demonstrated promising speech diagnostic potential. Conclusions: The results highlight the need to consider the validity of measures in the context of multisubsystem involvement. Our preliminary findings further suggest that the one-third octave analysis may be an optimal approach to quantify hypernasality and voice abnormalities in the presence of multisystem speech impairment. Future evaluation of the diagnostic accuracy of the one-third octave analysis is warranted.

Purpose: To compare vowel acoustics and intelligibility in words produced with and without contrastive stress by speakers with spastic (mixed-spastic) dysarthria secondary to cerebral palsy (DYS[subscript CP]) and healthy controls (HCs). Method: Fifteen participants (9 men, 6 women; age M = 42 years) with DYS[subscript CP] and 15 HCs (9 men, 6 women; age M = 36 years) produced sentences containing target words with and without contrastive stress. Forty-five healthy listeners (age M = 25 years) completed a vowel identification task of DYS[subscript CP] productions. Vowel acoustics were compared across stress conditions and groups using 1st (F1) and 2nd (F2) formant measures. Perceptual intelligibility was compared across stress conditions and dysarthria severity. Results: F1 and F2 significantly increased in stressed words for both groups, although the degree of change differed. Mean Euclidian distance between vowels also increased with stress. The relative probability of vowels falling within the target F1 × F2 space was greater for HCs but did not differ with stress. Stress production resulted in greater listener vowel identification accuracy for speakers with mild dysarthria. Conclusions: Contrastive stress affected vowel formants for both groups. Perceptual results suggest that some speakers with dysarthria may benefit from a contrastive stress strategy to improve vowel intelligibility.

Although tongue twisters have been widely use to study speech production in healthy speakers, few studies have employed this methodology for individuals with speech impairment. The present study compared tongue twister errors produced by adults with dysarthria and age-matched healthy controls. Eight speakers (four female, four male; mean age = 54.5 years) with spastic (mixed-spastic) dysarthria of varying aetiology (cerebral palsy, multiple sclerosis, multiple system atrophy) and eight controls (four female, four male; mean age = 56.9 years) were audio-recorded producing tongue twisters. One word in each tongue twister was marked for prominence. Speakers with dysarthria produced significantly more errors and spoke slower than healthy controls. The effect of prominence was significant for both groups--words spoken with prosodic prominence were significantly less error prone compared with words without prominence. While both groups produced most errors on words in the third position (of four-word utterances), speakers with dysarthria also produced high rates of errors on the first and fourth words. This preliminary investigation demonstrated the promise of applying the tongue twister paradigm to speakers with dysarthria and contributes to the evidence base for the implementation of prosodic strategies in speech intervention.

Purpose: A review of the salient characteristics of motor speech disorders and common assessment protocols revealed the need for a novel reading passage tailored specifically to differentiate between and among the dysarthrias (DYSs) and apraxia of speech (AOS). Method: "The Caterpillar" passage was designed to provide a contemporary, easily read, contextual speech sample with specific tasks (e.g., prosodic contrasts, words of increasing length and complexity) targeted to inform the assessment of motor speech disorders. Twenty-two adults, 15 with DYS or AOS and 7 healthy controls (HC), were recorded reading "The Caterpillar" passage to demonstrate its utility in examining motor speech performance. Conclusion: Analysis of performance across a subset of segmental and prosodic variables illustrated that "The Caterpillar" passage showed promise for extracting individual profiles of impairment that could augment current assessment protocols and inform treatment planning in motor speech disorders. (Contains 3 figures and 2 tables.)

Purpose: In this study, the authors compared indirect estimates of jaw-muscle tension in children with suspected muscle-tone abnormalities with age- and gender-matched controls. Method: Jaw movement and muscle activation were measured in children (ages 3 years, 11 months, to 10 years) with suspected muscle-tone abnormalities (Down syndrome or spastic cerebral palsy; n = 10) and controls (n = 11). Two measures were used to infer jaw tension: a kinematic index of mass-normalized stiffness and electromechanical delay (EMD). The kinematic index used video-based kinematics to obtain the slope of the peak velocity-displacement relationship. The EMD was derived from the interval between the onset of suprahyoid muscle activity and the onset of jaw depression. Results: Neither measure differentiated the groups. The kinematic index revealed differences between stressed and unstressed syllables in 3-syllable productions by the participants with cerebral palsy and controls, but not in 2-syllable productions by the participants with Down syndrome and controls. Conclusion: This preliminary investigation included the novel application of 2 measures to infer the jaw-muscle tension of children with suspected tone abnormalities. Although the results do not support the hypothesis that suspected muscle-tone abnormalities affect jaw movement sufficiently to influence speech production, considerations for interpreting the findings include methodological limitations and possible compensatory muscle coactivation.

The development of respiratory drive for vocalization was studied by observing chest wall kinematics longitudinally in 4 typically developing children from the age of 9 to 48 months. Measurements of the relative contribution of rib cage and abdominal movement during vocalization (i.e., babbling and true words) and rest breathing were obtained every 3 months using respiratory plethysmography (RespitraceTM). Extending earlier findings in 15-month-olds, 2 methods of analysis of rib cage and abdominal movement were used: (a) a dynamic index of the strength of coupling between the rib cage and abdomen, and (b) a classification scheme describing the moment-by-moment changes in each of the 2 components (C. A. Moore, T. J. Caulfield, & J. R. Green, 2001). The developmental course of relative chest wall kinematics differed between vocalization and rest breathing. The coupling of rib cage and abdomen during vocalization weakened significantly with development, whereas it remained consistently strong for rest breathing throughout the observed period. The developmental changes in frequency of occurrence of relative moment-by-moment changes varied across movement type. The results support previous findings that speech breathing is distinct from rest breathing based on the relative contributions of the rib cage and abdomen. Longitudinal changes are likely responsive to anatomic development, including changes to rib cage shape and compliance.

Keywords: children, prosody, rate reduction, loudness modification, intelligibility Vowel production contributes to the intelligibility of individuals with motor speech disorders. In adults with dysarthria, rate reduction and increased loudness have been shown to improve intelligibility partly because of changes in vowel production. The impact of prosodic modulation on vowel acoustics and intelligibility in children with motor speech impairment (MSI), however, is unclear. The current investigation aimed to provide perceptual and acoustic data from three children (ages 3 years, 6 months to 8 years, 6 months) with motor programming deficits producing utterances in four conditions: (1) habitual, (2) increased loudness, (3) slowed rate, and (4) emphatic stress. Additional acoustic data were collected from three healthy age-matched control participants (ages 4 years, 1 month to 8 years, 10 months). For each condition, utterances containing three corner vowels (/i/, /a/, /u/) were elicited using an audio-visualization technique. Perceptual intelligibility was based on judgments of 12 unfamiliar listeners. The impact of prosodic strategies varied across speakers, with two children with MSI demonstrating increased vowel intelligibility in at least one modulation condition. Acoustic analyses included first (F1) and second (F2) formant extraction and comparison of variance across conditions. F2 variance was greater for the children with MSI.These preliminary findings shed light on the interaction between prosodic modulation and intelligibility in childhood MSI and warrant further investigation., INTRODUCTION Prosodic modulation strategies are commonly used to improve intelligibility in motor speech disorders (dysarthria and apraxia of speech). Global prosodic strategies entail modulating a prosodic feature (e.g., rate, intensity) [...]

Keywords: cerebral palsy, dysarthria, prosody, children, intelligibility Exaggerated and redundant prosodic cue use has been noted among adults with dysarthria secondary to cerebral palsy (CP) (Patel, 2004; van Doom & Sheard, 2001). A possible explanation may be that speakers heighten prosodic contrasts to increase intelligibility. The current work examined whether children with dysarthria due to CP also produce exaggerated prosodic contours and, if so, how prosodic cue use in these speakers impacts intelligibility. Acoustic analyses were conducted on a previously collected dataset of two- to seven-word utterances produced by fourteen children with CP (seven with dysarthria and seven without) (Hustad, Gorton, & Lee, 2010). The dataset also included sentence-level transcriptions obtained from five listeners per speaker. Word intelligibility scores were derived from these transcripts and used to determine whether prosodic modulation differed for words with high versus low intelligibility. Although mean fundamental frequency ([F.sub.0]) and intensity range were similar across groups, words produced by children with dysarthria were slower and more variable in [F.sub.0] than the group without dysarthria. Moreover, intelligibility decreased when children with dysarthria increased [F.sub.0] and duration beyond the range used by children without dysarthria. Thus, findings suggest that interventions targeting appropriate prosody may be beneficial in improving intelligibility in children with dysarthria and CP., INTRODUCTION Cerebral palsy (CP) is a congenital motor disorder with prevalence estimates of approximately three per 1000 children (Arneson et al., 2009). Studies suggest that 60% of children with CP [...]

Exaggerated and redundant prosodic cue use has been noted among adults with dysarthria secondary to cerebral palsy (CP) (Patel, 2004; van Doorn & Sheard, 2001). A possible explanation may be that speakers heighten prosodic contrasts to increase intelligibility. The current work examined whether children with dysarthria due to CP also produce exaggerated prosodic contours and if so, how prosodic cue use in these speakers impacts intelligibility. Acoustic analyses were conducted on a previously collected dataset of 2-7 word utterances produced by fourteen children with CP (7 with dysarthria and 7 without) (Hustad, Gorton & Lee, 2010). The dataset also included sentence-level transcriptions obtained from five listeners per speaker. Word intelligibility scores were derived from these transcripts and used to determine whether prosodic modulation differed for words with high versus low intelligibility. Although mean fundamental frequency (F0) and intensity range were similar across groups, words produced by children with dysarthria were slower and more variable in F0 than the group without dysarthria. Moreover, intelligibility decreased when children with dysarthria increased F0 and duration beyond the range used by children without dysarthria. Thus findings suggest that interventions targeting appropriate prosody may be beneficial in improving intelligibility in children with dysarthria and CP.