One well-controlled study shows some evidence of effect of two interventions for childhood apraxia of speech (CAS)

Review question
What treatments help to improve the speech and language of children and adolescents with childhood apraxia of speech (CAS).

Background
Children with CAS find it difficult to produce sounds and syllables consistently and precisely in order to speak words and sentences with clarity and correct speech rhythm. As a result, children with CAS can be hard to understand with potential for negative impacts on school achievement and peer friendships. CAS affects around 0.1% of the general population. This review collates the research evidence to identify the most effective therapies for children with CAS.

Search date
The evidence is current to 6 April 2017.

Study characteristics
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.

Study funding sources
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.

Key results
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.

Quality of the evidence
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.

Recommendations
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.

Authors' conclusions: 

There is limited evidence that, when delivered intensively, both the 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.

Read the full abstract...
Background: 

Childhood apraxia of speech (CAS) affects a child's ability to produce sounds and syllables precisely and consistently, and to produce words and sentences with accuracy and correct speech rhythm. It is a rare condition, affecting only 0.1% of the general population. Consensus has been reached that three core features have diagnostic validity: (1) inconsistent error production on both consonants and vowels across repeated productions of syllables or words; (2) lengthened and impaired coarticulatory transitions between sounds and syllables; and (3) inappropriate prosody (ASHA 2007). A deficit in motor programming or planning is thought to underlie the condition. This means that children know what they would like to say but there is a breakdown in the ability to programme or plan the fine and rapid movements required to accurately produce speech. Children with CAS may also have impairments in one or more of the following areas: non-speech oral motor function, dysarthria, language, phonological production impairment, phonemic awareness or metalinguistic skills and literacy, or combinations of these. High-quality evidence from randomised controlled trials (RCTs) is lacking on interventions for CAS.

Objectives: 

To assess the efficacy of interventions targeting speech and language in children and adolescents with CAS as delivered by speech and language pathologists/therapists.

Search strategy: 

We searched CENTRAL, MEDLINE, Embase, eight other databases and seven trial registers up to April 2017. We searched the reference lists of included reports and requested information on unpublished trials from authors of published studies and other experts as well as information groups in the areas of speech and language therapy/pathology and linguistics.

Selection criteria: 

RCTs and quasi-RCTs of children aged 3 to 16 years with CAS diagnosed by a speech and language pathologist/therapist, grouped by treatment types.

Data collection and analysis: 

Two review authors (FL, AM) independently assessed titles and abstracts identified from the searches and obtained full-text reports of all potentially relevant articles and assessed these for eligibility. The same two authors extracted data and conducted the 'Risk of bias' and GRADE assessments. One review author (EM) tabulated findings from excluded observational studies (Table 1).

Main results: 

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.

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. 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.

There is limited evidence that, when delivered intensively, both the 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.

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