A systematic review and exploratory multi-level meta-analysis on psychological interventions for adults who stutter

Stuttering is a speech disorder and adults who stutter (AWS) often suffer from psychological symptoms. Although psychological interventions have been implemented with AWS, qualitative and quantitative synthesis of the resulting evidence is lacking. Therefore, we conducted a systematic review and exploratory multilevel meta-analysis of psychological interventions for AWS. Twenty-four studies were included in the review, and data from the 13 selected studies were synthesized, from which the standardized mean difference in pre-post comparisons was appropriately estimated (n = 311, 85 effect sizes). Cognitive behavioral therapy (n = 191, 53 effect sizes) or mindfulness and/or acceptance interventions (n = 94, 22 effect sizes) were used with AWS in most of the synthesized studies. Overall, psychological interventions were efficacious in ameliorating psychological symptoms for AWS (ĝ = 0.63, 95% CI [0.49, 0.76]). Furthermore, significant interaction effects between outcome and intervention types were observed. We also found that effects of mental rehearsal, which was specifically developed in Japan, were explained by long intervention duration. Implications for psychological interventions for AWS are discussed.