Attentional Regulation in Young Twins With Probable Stuttering, High Nonfluency, and Typical Fluency

Purpose: Using a sample of 20,445 Dutch twins, this study examined the relationship between speech fluency and attentional regulation in children. A secondary objective was to identify etiological overlap between nonfluency and poor attention using fluency-discordant twin pairs. Method: Three fluency groups were created at age 5 using a parent questionnaire: (a) probable stuttering (PS; N = 826; 4.0%), highly nonfluent (HNF; N = 547; 2.7%), and typically fluent (TF; N = 19,072; 93%). Multiple scales assessing attention, primarily self-regulation/inhibition, were obtained from both parents when children were ages 5 and 7 and from teachers when children were age 7. Results: When compared with the TF controls, both the PS and HNF children received higher (i.e., more problematic) scores on parental attention ratings at both ages (p <.002). Effect sizes were moderate for both groups. Teacher and parent ratings were generally comparable. The discordant co-twin analyses suggested that nonfluency and attention were influenced by potentially overlapping genetic and shared environmental factors. Conclusions: The liability to express both high nonfluency and problems with self-regulation/inhibition may arise from a common set of pathogenic mechanisms. This supports emerging models of stuttering, which propose that poor fluency may be part of a broader network of impaired self-regulatory processes. © American Speech-Language-Hearing Association.