Effects of syntactic complexity on sentence production abilities and their relation to working memory for children who stutter

Objectives: The purpose of this study was to investigate the sentence production abilities of children who stutter (CWS) and children who do not stutter (CWNS), and to explore the relationship between working memory capacity and sentence production ability for Korean-speaking CWS. Methods: Twenty children (10 CWS and 10 CWNS) with an age range of 6 to 12 years participated in the study. The sentence production task (SPT) consisted of two task types, and each task contained two syntactic structures varying the canonicity of word order. Digit span tasks were used as working memory measures. Results: A four-way mixed ANOVA revealed the two-way interactions were significant. The sentence type x task interaction indicated that differences in sentence types were greater in the completion than the priming tasks. The task type×canonicity suggested that canonicity effects were greater in priming than completion tasks. The sentence type×canonicity interaction revealed that greater differences in non-canonical sentences emerged in active sentences. There were significant correlations between working memory (WM) and some measures of sentence production conditions for CWS, whereas all correlations were significant among WM measures and sentence types in priming task for CWNS. Conclusion: Even though the two groups did not differ in SPT, all participants were affected by sentence type and canonicity, indicating that sentence type and word order need to be considered when evaluating Korean-speakers' sentence production abilities. More studies need to be conducted to further examine the relationship between WM capacity and disfluencies.