Abstract: This review includes only one RCT, funded by the Australian Research Council; the University of Sydney International Development Fund; Douglas and Lola Douglas Scholarship on Child and Adolescent Health; Nadia Verrall Memorial Scholarship; and a James Kentley Memorial Fellowship. This study recruited 26 children aged 4 to 12 years, with mild to moderate CAS of unknown cause, and compared two interventions: the Nuffield Dyspraxia Programme-3 (NDP-3); and the Rapid Syllable Transitions Treatment (ReST). Children were allocated randomly to one of the two treatments. Treatments were delivered intensively in one-hour sessions, four days a week for three weeks, in a university clinic in Australia. Speech pathology students delivered the treatments in the English language. Outcomes were assessed before therapy, immediately after therapy, at one month and four months post-therapy. Our review looked at one-month post-therapy outcomes only. A number of cases in each cohort had recommenced usual treatment by their speech and language pathologist between one month and four months post-treatment (NDP-3: 9/13 participants; ReST: 9/13 participants). Hence, maintenance of treatment effects to four months post-treatment could not be analysed without significant potential bias, and thus this time point was not included for further analysis in this review. We judged all core outcome domains to be low risk of bias. We downgraded the quality of the evidence by one level to moderate due to imprecision, given that only one RCT was identified. Both the NDP-3 and ReST therapies demonstrated improvement at one month post-treatment. For three outcomes the effect was marginally greater for NDP-3 than ReST: accuracy of production on treated words (NDP-3 mean difference (MD) = 36.0, ReST MD = 33.9; absolute MD = 2.1 between groups); speech production consistency, measured by 25 real words repeated three times using the inconsistency subtest of the Diagnostic Evaluation of Articulation and Phonology (DEAP) test (NDP-3 MD = 11.1, ReST MD = 10.9; absolute MD = 0.2 between groups); and accuracy of connected speech, assessed by imitated word accuracy in connected speech of at least three word combinations (NDP-3 MD = 14.3, ReST MD = 11.5; absolute MD = 2.8 between groups). ReST (MD = 18.3) demonstrated a marginally greater effect than NDP-3 (MD = 18.2) for accuracy of production on non-treated words at one month post-treatment (absolute MD = 0.1 between groups). The study did not assess the outcome of functional communication. There is limited evidence that, when delivered intensively, both NDP-3 and ReST may effect improvement in word accuracy in 4- to 12-year-old children with CAS, measured by the accuracy of production on treated and non-treated words, speech production consistency and the accuracy of connected speech. The study did not measure functional communication. No formal analyses were conducted to compare NDP-3 and ReST by the original study authors, hence one treatment cannot be reliably advocated over the other. We are also unable to say whether either treatment is better than no treatment or treatment as usual. No evidence currently exists to support the effectiveness of other treatments for children aged 4 to 12 years with idiopathic CAS without other comorbid neurodevelopmental disorders. Further RCTs replicating this study would strengthen the evidence base. Similarly, further RCTs are needed of other interventions, in other age ranges and populations with CAS and with co-occurring disorders.

Plain-language summary: We found one study with 26 children aged 4 to 12 years with CAS. The children had mild to severe CAS without a known cause. Children were allocated randomly (using a method like coin tossing) to one of two treatments: the Nuffield Dyspraxia Programme - Third Edition (NDP-3); and the Rapid Syllable Transition treatment (ReST). Both therapies were delivered intensively in one-hour sessions, four days a week for three weeks. The treatments were delivered by speech pathology students in a university clinic. Outcomes were assessed before therapy, immediately after therapy, at one month and four months post-therapy. Our review looked at one-month post-therapy outcomes only. The included study was funded by the Australian Research Council; the University of Sydney International Development Fund; Douglas & Lola Douglas Scholarship on Child and Adolescent Health; Nadia Verrall Memorial Scholarship; and a James Kentley Memorial Fellowship. Further studies replicating these findings would strengthen available evidence. The study provides limited evidence that the NDP-3 may improve the accuracy of production on treated items and the accuracy of connected speech. There is limited evidence that the NDP-3 has a negligible effect on speech production consistency, and the ReST a negligible effect on accuracy of production on non-treated words. The study did not measure functional communication. The included study was a randomised controlled trial with an overall low risk of bias. We downgraded the quality of the evidence by one level to moderate, due to imprecision, given that only one RCT was identified. There is limited evidence that the NDP-3 or ReST may be helpful for children with CAS of unknown origin, aged 4 to 12 years, without other co-occurring conditions. We were not able to find out whether one of these treatment was better than the other, or whether either was better than no treatment or treatment as usual. There is currently no available evidence for other treatments. Further RCTs — including studies comparing treatments to a no-treatment (wait-list) control group — would strengthen the evidence base. Further research is also needed for children with CAS and other disorders or diagnoses.