The relationship between grammatical development and disfluencies in preschool children who stutter and those who recover

Purpose: The dual diathesis stressor model indicates that a mismatch between a child’s endogenous linguistic abilities and exogenous linguistic contexts is one factor that contributes to stuttering behavior. In the present study, we used a developmental framework to investigate if reducing the gap between endogenous and exogenous linguistics factors would result in less disfluency for typical children, children who recover from stuttering (CWS-R), and children who persist. Method: Children between 28 and 43 months of age participated in this study: 8 typical children, 5 CWS-R, and 8 children who persist. The children were followed for 18 months with language samples collected every 6 months. The Index of Productive Syntax (Scarborough, 1990) served as a measure of endogenous grammatical ability. Length and complexity of active declarative sentences served as a measure of exogenous linguistic demand. A hierarchical linear model analysis was conducted using a mixed-model approach. Results: The results partially corroborate the dual diathesis stressor model. Disfluencies significantly decreased in CWS-R as grammatical abilities (not age) increased. Language development may serve as a protective factor or catalyst for recovery for CWS-R. As grammatical ability grew and the gap between linguistic ability and demand decreased; however, none of the three groups was more likely to produce disfluencies in longer and more complex utterances.