Purpose: This article presents the results of a meta-analysis to determine the effect of augmentative and alternative communication (AAC) on the speech production of individuals with developmental disabilities. Method: A comprehensive search of the literature published between 1975 and 2003, which included data on speech production before, during, and after AAC intervention, was conducted using a combination of electronic and hand searches. Results: The review identified 23 studies, involving 67 individuals. Seventeen of these studies did not establish experimental control, thereby limiting the certainty of evidence about speech outcomes. The remaining 6 studies, involving 27 cases, had sufficient methodological rigor for the “best evidence analysis” (cf. R. E. Slavin, 1986). Most of the participants (aged 2–60 years) had mental retardation or autism; the AAC interventions involved instruction in manual signs or nonelectronic aided systems. None of the 27 cases demonstrated decreases in speech production as a result of AAC intervention, 11% showed no change, and the majority (89%) demonstrated gains in speech. For the most part, the gains observed were modest, but these data may underestimate the effect of AAC intervention on speech production because there were ceiling effects. Conclusions: Future research is needed to better delineate the relationship between AAC intervention and speech production across a wider range of participants and AAC interventions.

Purpose: This systematic review aimed to determine the effects of augmentative and alternative communication (AAC) intervention on speech production in children with autism or pervasive developmental disorder-not otherwise specified. Method: A systematic review methodology was utilized to limit bias in searching, selecting, coding, and synthesizing relevant treatment studies. This involved a multifaceted search for studies written between 1975 and May 2007 using various bibliographic databases, dissertation databases, hand searches of selected journals and published compilations of AAC theses and dissertations, and ancestry searches. To be included, studies had to meet stringent criteria. A coding manual and form facilitated data extraction in terms of participant characteristics, treatment characteristics, design and measurement, and outcomes. Results: Nine single-subject experimental design (27 participants) and 2 group studies (98 participants) were included. Results indicated that AAC interventions do not impede speech production. In fact, most studies reported an increase in speech production. However, in-depth analyses revealed that the gains were rather modest. Conclusions: Although AAC interventions do not appear to impede speech production and may result in increased speech production, the modest gains observed require realistic expectations among clinicians and other stakeholders. Future research should be more hypothesis driven and aim to identify predictive child characteristics, such as prior speech imitation and object exploration skills.

Systematic reviews can be a tremendous asset in the implementation of evidence-based practice, because they minimize some of the most-documented barriers to evidence-based practice. For example, by reading systematic reviews, clinicians may save time that would otherwise be dedicated to locating and appraising individual studies. Further, clinicians can rely on someone else's reviewing expertise, which reduces the knowledge and skill burden otherwise imposed on them. However, empirical studies have repeatedly demonstrated that there is great variability in the quality of systematic reviews. Thus, in order to harness their potential, it is imperative that clinicians distinguish high-quality systematic reviews from those of low quality. In this paper, we aim to discuss considerations for appraising the quality of systematic reviews.

Background: Efficient library searches for research evidence are critical to practitioners who wish to engage in evidence‐based practice (EBP) as well as researchers who seek to develop systematic reviews. Aims: This review will propose the benefits of the search technique ‘Pearl Growing’ (‘Traditional Pearl Growing’) as well as an adaptation of this technique (‘Comprehensive Pearl Growing’), until now ignored by the literature on EBP and systematic reviews, to aid in the retrieval of research evidence. These search techniques are illustrated with examples from the field of augmentative and alternative communication. Main Contributions: Traditional Pearl Growing is proposed as an important addition to the arsenal of EBP search strategies for practitioners. The literature on Traditional Pearl Growing is extended in that EBP presents a newly identified purpose for this technique and the benefits in identifying appropriate quality filter goes beyond its previously exclusive focus on keywords. Comprehensive Pearl Growing is projected as a new strategy for researchers searching for studies to be included in systematic reviews. Not only does it provide data‐based guidance in selecting effective keywords and quality filters, but also it provides appropriate databases. Conclusions: Although the techniques Traditional Pearl Growing and Comprehensive Pearl Growing are believed to be useful for locating research evidence in any field, it may be particularly important for interdisciplinary topics where the use of effective controlled vocabulary plays a greater role in bringing together evidence that may be scattered across databases.

An evidence-based practice (EBP) approach to clinical and educational practice emphasizes the importance of integrating sound research evidence into the decision-making process. This paper provides a discussion of the relevance of EBP to the field of augmentative and alternative communication (AAC). Included is an examination of what is currently known about decision-making in AAC, as well as a brief history of EBP and its application in other fields. A definition of EBP in AAC is proposed and a schematic of the EBP process is described, including proposed design hierarchies of evidence. This process is then illustrated with a case example. Finally, key factors for the adoption of EBP in AAC are discussed.