To date there have been a number of systematic literature reviews that have examined the effectiveness of interventions for children with speech sound disorders (SSD). Generally the results of these reviews have been encouraging although they have often highlighted the fact that much of the evidence is at a relatively low level and that therefore currently, the relative effectiveness of one intervention over another in particular instances is not clear.
Furthermore, for interventions to be appropriately targeted to subgroups of children, it is important to determine which interventions are most effective with which children in which contexts. It was the purpose of this systematic review to assess these variables. This question reflects a realist perspective  which recognises that complex interventions targeting complex problems cannot necessarily be rigidly applied but will be adapted by individuals (i.e. therapists) for individuals (in this case, children).
The review was part of a larger review investigating all interventions for preschool children with primary speech and language impairments. Thus the search strings were wide ranging and included key words pertaining to speech, language, communication, developmental disorders and paediatrics, as well as research design. Sixteen databases including Cinahl, Embase and Medline were searched, for peer-reviewed English-language publications, between January 1980 and November 2011.
The search generated fifty five thousand two hundred and seventy one publications which were then reviewed and excluded, following Cochrane guidelines and specified inclusion/exclusion criteria, by a trained team of research speech and language therapists and psychologists. Inclusion criteria for study design were kept broad in order to allow for the exploration of contextual influences. Two hundred and four publications met the search criteria. The remaining publications were then quality assessed using the PEDro scale (Physiotherapy Evidence Database) and the Single Case Experimental Design (SCED) scale - critical appraisal tools examining factors such as clear eligibility criteria, random allocation, allocation concealment, blinding, baseline comparisons, intention to treat analysis, appropriateness of statistical comparisons.
A preliminary examination of the studies identified the primary focus of the intervention along with the key outcomes measured. From this, 81 papers were identified that focused on interventions for speech sound disorders. These 81 papers are the focus of this presentation.
Manuscripts identified in the speech sound disorders section were predominantly case series and non-randomised, small group designs, incorporating such devices as multiple and staggered baselines, and AB(A) designs. There were also two retrospective reviews of case notes, seven single case studies and six randomised controlled trials. The number of children included in each study ranged from 1 to 1009, with a mean of 44 and a median of 11.
The paper will present which interventions have been used with specific subgroups of children (both in terms of age and speech sound disorder subgroups). It will present the results of the quality appraisal showing the varying quality of research and make recommendations regarding the design and reporting of intervention studies for the future. The paper will also discuss the implications of the review findings for current practice.