Effects of Physiological Arousal on Speech Motor Control and Speech Motor Practice in Preschool-Age Children Who Do and Do Not Stutter.

Victoria Tumanova,Carly Woods,Qiu Wang

doi:10.1044/2020_jslhr-20-00092

Abstract

Purpose We examined the effects of physiological arousal on speech motor control and speech motor practice effects in preschool-age children who do (CWS) and do not stutter (CWNS). Method Participants included 18 CWS (M age = 4 years 5 months) and 18 age- and gender-matched CWNS. The participants repeated a phrase "buy bobby a puppy" interspersed with viewing pictures from the International Affective Picture System under two experimental conditions speaking after viewing pictures with (a) negative and (b) neutral valence. Participants' lip movements were tracked using Optotrak system. The spatiotemporal index and mean utterance duration were calculated to examine speech motor control and speech motor practice effects. Skin conductance level was measured during the experimental conditions to assess participants' physiological level of arousal. Results Preschool-age CWS demonstrated greater speech movement variability across all conditions and trials than CWNS. Furthermore, the younger participants produced more variable articulatory movements than the older participants. Participants' speech movement variability did not significantly differ between the negative and neutral experimental conditions, and the level of physiological arousal did not have a significant effect on it. There was a nonsignificant trend of decrease in speech movement variability across the repeated trials in both groups. Last, CWS and CWNS did not differ in their mean utterance duration, suggesting that their articulation rate was similar across all conditions and trials. Conclusions Our findings indicate that, compared to preschool-age CWNS, CWS demonstrate less mature speech motor control. However, present findings do not support the hypothesis that CWS benefit less from motor practice relative to CWNS. Given that our conditions elicited similar levels of arousal in the participants, future research is needed to examine whether physiological arousal disrupts speech motor control in preschool-age children potentially contributing to disruptions of speech fluency and the development of stuttering.

Highlights

Variations in speech motor control in stressful speaking situations have been reported in both normally fluent and stuttering adults (Arenas & Zebrowski, 2013; Caruso, Chodzko-Zajko, Bidinger, & Sommers, 1994; van Lieshout, Ben-David, Lipski, & Namasivayam, 2014; Jackson, Tiede, Beal, & Whalen, 2016), with the latter group showing greater effect of stress on speech than the former
Given the somewhat inconsistent findings on whether speech rate increases or decreases during emotional arousal and limited information regarding effects of physiological arousal on speech rate in preschool-age children, we examined the effects of arousal on mean utterance duration for the repeated productions of the same utterance in preschool-age CWS and CWNS in our study
We examined the articulatory kinematics in children as young as 3 years of age, which is very close to the typical age of stuttering onset

Summary

Introduction

Variations in speech motor control in stressful speaking situations have been reported in both normally fluent and stuttering adults (Arenas & Zebrowski, 2013; Caruso, Chodzko-Zajko, Bidinger, & Sommers, 1994; van Lieshout, Ben-David, Lipski, & Namasivayam, 2014; Jackson, Tiede, Beal, & Whalen, 2016), with the latter group showing greater effect of stress on speech than the former. For adults who stutter, an increase in stuttering frequency and severity has been observed when speaking under feared or stressful conditions, such as a challenging job interview (Caruso, Chodzko-Zajko, Bidinger, & Sommers, 1994; Brundage, Graap, Gibbons, Ferrer, & Brooks, 2006) These findings, cannot be extended to young children who stutter as their speech motor control and other skills are not yet mature and undergo development well into school-age years (Smith, 2006; Walsh & Smith, 2002; Walsh, Smith & Weber-Fox, 2006). Considering the evidence that stuttering is a neurodevelopmental multifactorial disorder with speech motor, linguistic, and temperamental domains implicated in its development (e.g., Smith & Weber, 2017), it is crucial to examine how emotional factors interact with speech motor factors and whether emotional factors promote or interfere with speech motor learning in developing systems of CWS

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