Articulatory Dynamics of Fluent Utterances of Stutterers and Nonstutterers

Purpose: The purpose of this study was to determine if indices of speech motor coordination during the production of sentences varying in sentence length and syntactic complexity were associated with stuttering persistence versus recovery in 5-to 7-year-old children. Methods: We compared children with persistent stuttering (CWS-Per) with children who had recovered (CWS-Rec), and children who do not stutter (CWNS). A kinematic measure of articulatory coordination, lip aperture variability (LAVar), and overall movement duration were computed for perceptually fluent sentence productions varying in length and syntactic complexity. Results: CWS-Per exhibited higher LAVar across sentence types compared to CWS-Rec and CWNS. For the participants who successfully completed the experimental paradigm, the demands of increasing sentence length and syntactic complexity did not appear to disproportionately affect the speech motor coordination of CWS-Per compared to their recovered and fluent peers. However, a subset of CWS-Per failed to produce the required number of accurate utterances. Conclusions: These findings support our hypothesis that the speech motor coordination of school-age CWS-Per, on average, is less refined and less mature compared to CWS-Rec and CWNS. Childhood recovery from stuttering is characterized, in part, by overcoming an earlier occurring maturational lag in speech motor development.

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confidence: 99%

A Lag in Speech Motor Coordination During Sentence Production Is Associated With Stuttering Persistence in Young Children

Usler

Smith

Weber

2017

“…Stutter-like disfluencies result from disruptions in the neural commands to the muscles necessary for fluent speech (e.g., Smith, 1989). These motor disruptions are observed in articulatory, laryngeal, and respiratory systems (Kleinow & Smith, 2000;Max & Gracco, 2005;Max, Guenther, Gracco, Ghosh, & Wallace, 2004;McClean & Runyan, 2000;Peters & Boves, 1988;Smith, 1989;Ward, 1997;Zimmermann, 1980). There is also evidence, though mixed, that children and adults who stutter (CWS and AWS, respectively) show less proficiency in nonspeech motor tasks (Brown, Zimmermann, Linville, & Hegmann, 1990;Caruso, Abbs, & Gracco, 1988;Cooper & Allen, 1977;Falk, Müller, & Bella, 2014;Forster & Webster, 2001;Howell, Au-Yeung, & Rustin, 1997;Max, Caruso, & Gracco, 2003;Neef et al, 2011;Olander, Smith, & Zelaznik, 2010;Ward, 1997;Webster, 1986;Westphal, 1933;Zelaznik, Smith, Franz, & Ho, 1997).…”

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confidence: 99%

Evidence That Bimanual Motor Timing Performance Is Not a Significant Factor in Developmental Stuttering

Hilger

Zelaznik

Smith

2016

Purpose: Stuttering involves a breakdown in the speech motor system. We address whether stuttering in its early stage is specific to the speech motor system or whether its impact is observable across motor systems. Method: As an extension of Olander, Smith, and Zelaznik (2010), we measured bimanual motor timing performance in 115 children: 70 children who stutter (CWS) and 45 children who do not stutter (CWNS). The children repeated the clapping task yearly for up to 5 years. We used a synchronization-continuation rhythmic timing paradigm. Two analyses were completed: a cross-sectional analysis of data from the children in the initial year of the study (ages 4;0 [years;months] to 5;11) compared clapping performance between CWS and CWNS. A second, multiyear analysis assessed clapping behavior across the ages 3;5-9;5 to examine any potential relationship between clapping performance and eventual persistence or recovery of stuttering. Results: Preschool CWS were not different from CWNS on rates of clapping or variability in interclap interval. In addition, no relationship was found between bimanual motor timing performance and eventual persistence in or recovery from stuttering. The disparity between the present findings for preschoolers and those of Olander et al. (2010) most likely arises from the smaller sample size used in the earlier study. Conclusion: From the current findings, on the basis of data from relatively large samples of stuttering and nonstuttering children tested over multiple years, we conclude that a bimanual motor timing deficit is not a core feature of early developmental stuttering. Stuttering is a speech production disorder characterized by disfluencies such as part-word repetitions, prolongations, and silent blocks. The etiology involves multiple factors, including motoric, linguistic, and psychosocial contributors (Conture, 1990;Smith, 1990;Starkweather, 1993;Van Riper, 1982;Wall & Myers, 1995). Stuttering onset generally occurs around 2-5 years of age with a 75% recovery rate for children who began to stutter in these years Watkins, Yairi, & Ambrose, 1999;. Stutter-like disfluencies result from disruptions in the neural commands to the muscles necessary for fluent speech (e.g., Smith, 1989). These motor disruptions are observed in articulatory, laryngeal, and respiratory systems (Kleinow & Smith, 2000;Max & Gracco, 2005;Max, Guenther, Gracco, Ghosh, & Wallace, 2004;McClean & Runyan, 2000;Peters & Boves, 1988;Smith, 1989;Ward, 1997;Zimmermann, 1980). There is also evidence, though mixed, that children and adults who stutter (CWS and AWS, respectively) show less proficiency in nonspeech motor tasks (Brown, Zimmermann, Linville, & Hegmann, 1990;Caruso, Abbs, & Gracco, 1988;Cooper & Allen, 1977;Falk, Müller, & Bella, 2014;Forster & Webster, 2001;Howell, Au-Yeung, & Rustin, 1997;Max, Caruso, & Gracco, 2003;Neef et al., 2011;Olander, Smith, & Zelaznik, 2010;Ward, 1997;Webster, 1986;Westphal, 1933;Zelaznik, Smith, Franz, & Ho, 1997).Extending the work of Olander et al. (2010), who found a large ...

“…This, in turn, may lead to group differences in kinematic characteristics of the resulting movement patterns (e.g., Alfonso, 1991; Ca ruso, Abbs, & Gracco, 1988;Van Lieshout, Alfonso, Hulstijn, & Peters, 1994;Van Lieshout et al, 1996;Zimmermann, 1980aZimmermann, , 1980b, and, indirectly, to group differences in the duration of acoustic events (e.g., Borden, 1983;Healey & Ramig, 1986;McMillian & Pindzola, 1986;Pindzola, 1987;Schäfersküpper & Dames, 1987;Starkweather & Meyers, 1979;Van Lieshout et al, 1996).…”

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confidence: 99%

From Planning to Articulation in Speech Production: What Differentiates a Person Who Stutters From a Person Who Does Not Stutter?

Lieshout

Hulstijn²,

Peters

1996

The main purpose of the present study was to differentiate between people who stutter and control speakers regarding their ability to assemble motor plans and to prepare (and execute) muscle commands. Adult males who stutter, matched for age, gender, and educational level with a group of control speakers, were tested on naming words and symbols. In addition, their ability to encode and retrieve memory representations of combinations of a symbol and a word, was tested in a recognition task, using manual reaction times and sensitivity scores, as defined in signa! detection theory, as performance measures. Group differences in muscle command preparation were assessed from electromyographic recordings of upper lip and lower lip. Results indicated no interaction between group and word size effects in choice reaction times or a group effect in the ability to recognize previously learned symbol-word combinations. However, they were significantly different in the timing of peak amplitudes in the integrated electromyographic signals o f upper lip and lower lip (IEMG peak latency). Findings question the claim that people who stutter have problems in creating abstract motor plans for speech. In addition, it is argued that the group differences in IEMG peak latency that were found in the present study might be better understood in terms of motor control strategies than in terms of motor control deficits.