Methodological standards in single-case experimental design: Raising the bar.

Single-case experimental designs (SCEDs), or small-n experimental research, are frequently implemented to assess approaches to improving outcomes for people with disabilities, particularly those with low-incidence disabilities, such as some developmental disabilities. SCED has become increasingly accepted as a research design. As this literature base is needed to determine what interventions are evidence-based practices, the acceptance of SCED has resulted in increased critiques with regard to methodological quality. Recent trends include recommendations from a number of expert scholars and institutions. The purpose of this article is to summarize the recent history of methodological quality considerations, synthesize the recommendations found in the SCED literature, and provide recommendations to researchers designing SCEDs with regard to essential and aspirational standards for methodological quality. Conclusions include imploring SCED to increase the quality of their experiments, with particular consideration regarding the applied nature of SCED research to be published in Research in Developmental Disabilities and beyond.

A systematic quality review of high-tech AAC interventions as an evidence-based practice.

Although high-tech augmentative and alternative communication (AAC) is commonly used to teach social-communication skills to people with autism spectrum disorder or intellectual disabilities who have complex communication needs, there is a critical need to evaluate the efficacy of this approach. The aim of this systematic review was to evaluate the quality of single-case experimental design research on the use of high-tech AAC to teach social-communication skills to individuals with autism spectrum disorder or intellectual disabilities who have complex communication needs, to determine if this intervention approach meets the criteria for evidence-based practices as outlined by the What Works Clearinghouse. Additionally, information on the following extended methodological standards is reported on all included studies: participant description, description of setting and materials, interventionist description, baseline and intervention description, maintenance, generalization, procedural integrity, and social validity. The results from 18 multiple-baseline or multiple-probe experiments across 17 studies indicate that using high-tech AAC to teach social-communication skills to individuals with autism spectrum disorder or intellectual disabilities and complex communication needs can be considered an evidence-based practice, although the review of comparison (i.e., alternating treatment) design studies did not indicate that high-tech AAC is significantly better than low-tech AAC.

High-technology augmentative and alternative communication for individuals with intellectual and developmental disabilities and complex communication needs: a meta-analysis.

The use of mobile technology is ubiquitous in modern society and is rapidly increasing in novel use. The use of mobile devices and software applications ("apps") as augmentative and alternative communication (AAC) is rapidly expanding in the community, and this is also reflected in the research literature. This article reports the social-communication outcome results of a meta-analysis of single-case experimental research on the use of high-tech AAC, including mobile devices, by individuals with intellectual and developmental disabilities, including autism spectrum disorder. Following inclusion determination, and excluding studies with poor design quality, raw data from 24 publications were extracted and included 89 A-B phase contrasts. Tau-U nonparametric, non-overlap effect size was used to aggregate the results across all studies for an omnibus and moderator analyses. Kendall's S was calculated for confidence intervals, p-values, and standard error. The omnibus analysis indicated overall low to moderate positive effects on social-communication outcomes for high-tech AAC use by individuals with intellectual and developmental disabilities.

The effects of video modeling in teaching functional living skills to persons with ASD: A meta-analysis of single-case studies.

BACKGROUND: Many individuals with autism spectrum disorders (ASD) show deficits in functional living skills, leading to low independence, limited community involvement, and poor quality of life. With development of mobile devices, utilizing video modeling has become more feasible for educators to promote functional living skills of individuals with ASD. AIMS: This article aims to review the single-case experimental literature and aggregate results across studies involving the use of video modeling to improve functional living skills of individuals with ASD. METHODS AND PROCEDURES: The authors extracted data from single-case experimental studies and evaluated them using the Tau-U effect size measure. Effects were also differentiated by categories of potential moderators and other variables, including age of participants, concomitant diagnoses, types of video modeling, and outcome measures. OUTCOMES AND RESULTS: Results indicate that video modeling interventions are overall moderately effective with this population and dependent measures. While significant differences were not found between categories of moderators and other variables, effects were found to be at least moderate for most of them. CONCLUSIONS AND IMPLICATIONS: It is apparent that more single-case experiments are needed in this area, particularly with preschool and secondary-school aged participants, participants with ASD-only and those with high-functioning ASD, and for video modeling interventions addressing community access skills.

AAC Interventions for Individuals with Autism Spectrum Disorders: State of the Science and Future Research Directions.

Augmentative and alternative communication (AAC) provides a means of effective communication to individuals with autism spectrum disorder (ASD), many of whom are unable to use conventional speech effectively. The purposes of this article are (a) to summarize and synthesize the last few decades of research on the use of AAC with people with ASD; (b) to indicate implications of this research for stakeholders such as people with ASD, their family members, and educators with whom they work; and (c) to outline priorities for future research to improve communication and other outcomes for individuals with ASD and their loved ones. People with ASD stand to greatly benefit from AAC, particularly with current AAC technologies, as described in this article.

An Evaluation of the Quality of Research on Evidence-Based Practices for Daily Living Skills for Individuals with Autism Spectrum Disorder.

This study presents a literature review of interventions for improving daily living skills of individuals with ASD. This review investigated the quality of the design and evidence of the literature base and determined the state of the evidence base related to interventions for improving daily living skills of individuals with ASD. Included studies were evaluated to determine the overall quality of the evidence for each design within each article, based on the What Works Clearinghouse standards for single-case experimental design (Kratochwill et al. 2010), adapted by Maggin et al. (Remedial Spec Educ 34(1):44-58, 2013. doi: 10.1177/0741932511435176 ). As a result, video modeling was found to be an evidence-based practice. Limitations and implications for future research and for practitioners are discussed.

Impact of PECS tablet computer app on receptive identification of pictures given a verbal stimulus.

OBJECTIVE: The purpose of this brief report was to determine the effect on receptive identification of photos of a tablet computer-based augmentative and alternative communication (AAC) system with voice output. METHODS: A multiple baseline single-case experimental design across vocabulary words was implemented. One participant, a preschool-aged boy with autism and little intelligible verbal language, was included in the study. RESULTS: Although a functional relation between the intervention and the dependent variable was not established, the intervention did appear to result in mild improvement for two of the three vocabulary words selected. CONCLUSION: The authors recommend further investigations of the collateral impacts of AAC on skills other than expressive language.

Interaction of participant characteristics and type of AAC with individuals with ASD: a meta-analysis.

Individuals with autism spectrum disorders (ASD) and complex communication needs often rely on augmentative and alternative communication (AAC) as a means of functional communication. This meta-analysis investigated how individual characteristics moderate effectiveness of three types of aided AAC: the Picture Exchange Communication System (PECS), speech-generating devices (SGDs), and other picture-based AAC. Effectiveness was measured via the Improvement Rate Difference. Results indicated that AAC has small to moderate effects on speech outcomes, and that SGDs appear to be most effective when considering any outcome measure with individuals with ASD without comorbid intellectual/developmental disorders (IDD). PECS appears to be most effective when considering any outcome measure with individuals with ASD and IDD. SGDs and PECS were the most effective type of AAC for preschoolers, when aggregating across outcome measures. No difference was found between systems for elementary-aged and older individuals.

Moderation of effects of AAC based on setting and types of aided AAC on outcome variables: an aggregate study of single-case research with individuals with ASD.

OBJECTIVE: The purpose of this meta-analysis was to evaluate the potential moderating effects of intervention setting and type of aided augmentative and alternative communication (AAC) on outcome variables for students with autism spectrum disorders. METHODS: Improvement rate difference, an effect size measure, was used to calculate aggregate effects across 35 single-case research studies. RESULTS: Results indicated that the largest effects for aided AAC were observed in general education settings. With respect to communication outcomes, both speech generating devices (SGDs) and the Picture Exchange Communication System (PECS) were associated with larger effects than other picture-based systems. With respect to challenging behaviour outcomes, SGDs produced larger effects than PECS. CONCLUSION: This aggregate study highlights the importance of considering intervention setting, choice of AAC system and target outcomes when designing and planning an aided AAC intervention.

Effects of a self-monitoring device on socially relevant behaviors in adolescents with Asperger disorder: a pilot study.

This article reports the results of two case studies. Two middle school-aged participants with high-functioning autism spectrum disorders were taught to self-monitor behaviors impacting their social acceptance by peers in their general education settings: oral self-stimulatory behaviors and conversation skills. Results indicate that the intervention was effective to some degree with both participants. As a result of the self-monitoring intervention, one participant decreased self-stimulatory behaviors; however, his data were highly variable throughout the study though lower on average during intervention than in baseline. The other participant's targeted skills in communication were only slightly improved. Self-monitoring using a vibrating reminder appears to be a low-cost intervention with high levels of social acceptability, low training requirements for teachers or students, and no social stigma.

Impacts of a PECS instructional coaching intervention on practitioners and children with autism.

There is a growing research literature on the potential benefits of augmentative and alternative communication (AAC) for individuals with autism; however few studies have investigated implementation of AAC within real-life contexts. Thus, the purpose of this study was to investigate the impact of training for practitioners in implementation of aided AAC, and to examine implementation of Picture Exchange Communication System (PECS) in real-life contexts. In particular, this study involved the implementation of instructional coaching to increase opportunities offered by behavioral therapists for their preschool-aged clients to use PECS to make requests. Results indicated increases in therapist implementation of AAC and client use of AAC in trained contexts, with limited generalization to untrained contexts.

Effects of video modeling on communicative social skills of college students with Asperger syndrome.

INTRODUCTION: Empirical support regarding effective interventions for individuals with autism spectrum disorder (ASD) within a postsecondary community is limited. Video modeling, an empirically supported intervention for children and adolescents with ASD, may prove effective in addressing the needs of individuals with ASD in higher education. OBJECTIVE: This study evaluated the effects of video modeling without additional treatment components to improve social-communicative skills, specifically, eye contact, facial expression, and conversational turntaking in college students with ASD. METHOD: This study utilized a multiple baseline single-case design across behaviors for two post-secondary students with ASD to evaluate the effects of the video modeling intervention. RESULTS: Large effect sizes and statistically significant change across all targeted skills for one participant and eye contact and turntaking for the other participant were obtained. CONCLUSION: The use of video modeling without additional intervention may increase the social skills of post-secondary students with ASD. Implications for future research are discussed.

Effects of peer-mediated implementation of visual scripts in middle school.

Although research has investigated the impact of peer-mediated interventions and visual scripts on social and communication skills in children with autism spectrum disorders, no studies to date have investigated peer-mediated implementation of scripts. This study investigated the effects of peer-implemented scripts on a middle school student with autism, intellectual impairments, and speech-language impairment via a multiple baseline single-case research design across behaviors. The target student demonstrated improvements in three communicative behaviors when implemented by a trained peer; however, behaviors did not generalize to use with an untrained typically developing peer.

Moderating factors of video-modeling with other as model: a meta-analysis of single-case studies.

Video modeling with other as model (VMO) is a more practical method for implementing video-based modeling techniques, such as video self-modeling, which requires significantly more editing. Despite this, identification of contextual factors such as participant characteristics and targeted outcomes that moderate the effectiveness of VMO has not previously been explored. The purpose of this study was to meta-analytically evaluate the evidence base of VMO with individuals with disabilities to determine if participant characteristics and targeted outcomes moderate the effectiveness of the intervention. Findings indicate that VMO is highly effective for participants with autism spectrum disorder (IRD=.83) and moderately effective for participants with developmental disabilities (IRD=.68). However, differential effects are indicated across levels of moderators for diagnoses and targeted outcomes. Implications for practice and future research are discussed.

A meta-analysis of single case research studies on aided augmentative and alternative communication systems with individuals with autism spectrum disorders.

Many individuals with autism cannot speak or cannot speak intelligibly. A variety of aided augmentative and alternative communication (AAC) approaches have been investigated. Most of the research on these approaches has been single-case research, with small numbers of participants. The purpose of this investigation was to meta-analyze the single case research on the use of aided AAC with individuals with autism spectrum disorders (ASD). Twenty-four single-case studies were analyzed via an effect size measure, the Improvement Rate Difference (IRD). Three research questions were investigated concerning the overall impact of AAC interventions on targeted behavioral outcomes, effects of AAC interventions on individual targeted behavioral outcomes, and effects of three types of AAC interventions. Results indicated that, overall, aided AAC interventions had large effects on targeted behavioral outcomes in individuals with ASD. AAC interventions had positive effects on all of the targeted behavioral outcome; however, effects were greater for communication skills than other categories of skills. Effects of the Picture Exchange Communication System and speech-generating devices were larger than those for other picture-based systems, though picture-based systems did have small effects.

Meta-analysis of PECS with individuals with ASD: investigation of targeted versus non-targeted outcomes, participant characteristics, and implementation phase.

The Picture Exchange Communication System (PECS) is a widely used picture/icon aided augmentative communication system designed for learners with autism and other developmental disorders. This meta-analysis analyzes the extant empirical literature for PECS relative to targeted (functional communication) and non-targeted concomitant outcomes (behavior, social skills, and speech) for learners with autism, learners with autism and intellectual disabilities and those with autism and multiple disabilities. Effect size analyses were done using the Improvement Rate Difference method, an advanced metric. Effect sizes were independently analyzed for targeted and non-targeted outcomes, student age, learner disability, and number of phases in the PECS protocol acquired by learners. Results supported the judgment that PECS is a promising intervention method. Analysis also revealed that functional communication outcomes associated with the PECS protocol were most impacted, that preschool children and those with autism generally showed the strongest training effects, and that in general students who advanced through the most PECS protocol phases had the best outcomes.

Non-responsiveness to intervention: children with autism spectrum disorders who do not rapidly respond to communication interventions.

OBJECTIVE: Providing a detailed description of two participants who failed to acquire functional communication skills following a verbal modelling intervention and Picture Exchange Communication System (PECS) training. METHODS: Single-case research; Independent verbal requests, imitated verbal requests, word approximations and independent picture requests were assessed in a toddler and a pre-schooler with autism before and during two interventions. RESULTS: Although both participants used some vocalizations over the course of the study, experimental control was not demonstrated and the participants did not acquire a functional communication system prior to the cessation of intervention. CONCLUSIONS: Future research should include additional, detailed reports that provide insight to why some children with autism do not respond to particular communication interventions and should investigate the pairing of particular child characteristics with targeted interventions.

Impact of the picture exchange communication system: effects on communication and collateral effects on maladaptive behaviors.

Many children with autism require intensive instruction in the use of augmentative or alternative communication systems, such as the Picture Exchange Communication System (PECS). This study investigated the use of PECS with three young boys with autism to determine the impact of PECS training on use of pictures for requesting, use of intelligible words, and maladaptive behaviors. A multiple baseline-probe design with a staggered start was implemented. Results indicated that all of the participants quickly learned to make requests using pictures and that two used intelligible speech following PECS instruction; maladaptive behaviors were variable throughout baseline and intervention phases. Although all of the participants improved in at least one dependent variable, there remain questions regarding who is best suited for PECS and similar interventions.