A multilevel meta-analysis on effects of psychological interventions for adults who stutter

Introduction: It is recommended that empirically-supported psychological interventions should be provided for adults who stutter (AWS). A meta-analysis on efficacy of psychological interventions for AWS was conducted in the present study. Method: Studies which conducted psychological interventions were identified through a database (MEDLINE through PubMed) and other sources including previous reviews. Studies where pre-post effect sizes can be estimated were extracted and bias was assessed quantitatively. Then, multilevel meta-analysis was conducted where outcomes were nested within studies. Furthermore, multilevel moderation (meta-regression) analyses were conducted to investigate relationships between intervention effects and outcome and treatment types.Results and discussions: Cognitive behavioral therapy or mindfulness and/or acceptance interventions were applied for AWS in majority of included studies. When excluding studies or outcomes potentially affected by bias, overall intervention effects were equivalent between them. Exploratory moderation analyses suggested that effects of these interventions may depend on outcome types. The present multilevel meta-analysis should be updated to obtain more reliable results in the future.