A systematic review of interventions for adults who stutter

To examine the effectiveness of (i) face to face interventions (ii) models of service delivery and (iii) psychological treatments combined with speech-focused interventions for adults who stutter.

Five electronic databases and three clinical trial registries were searched. Systematic reviews, randomised controlled trials (RCTs) and studies that applied an intervention with adults who stutter were included. Pharmaceutical interventions were excluded. Primary outcomes included a measure of stuttering severity. Risk of bias assessment was conducted on included studies and overall quality of the evidence was graded.

Five RCTS, four registered trials and three systematic reviews met inclusion criteria. Intervention approaches included speech restructuring programs (e.g. Camperdown Program) and transcranial direct current stimulation (tDCS). One study investigated cognitive behaviour therapy (CBT) alongside speech restructuring. Overall, studies were classified low risk of bias and good quality. Speech restructuring was included in all but one study (tDCS study) and had the most evidence i.e. supported by the greatest number of RCTs. On average, stuttering frequency was reduced by 50-57 % using speech restructuring approaches. No study reduced stuttering to the same level as community controls who don't stutter. The study on tDCS reduced stuttering frequency by 22-27 %. Speech restructuring delivered via telehealth was non-inferior to face-to-face intervention. One study reported CBT was an effective adjunct to speech restructuring interventions.

Speech restructuring interventions were found to reduce stuttering in adults, however degree and maintenance of fluency varied. The body of evidence surrounding tDCS and psychological interventions is limited. Replication studies should be considered.