Systematic Review of Variables Related to Instruction in Augmentative and Alternative Communication Implementation: Group and Single-Case Design.

PURPOSE: This article provides a systematic review and analysis of group and single-case studies addressing augmentative and alternative communication (AAC) intervention with school-aged persons having autism spectrum disorder (ASD) and/or intellectual/developmental disabilities resulting in complex communication needs (CCNs). Specifically, we examined participant characteristics in group-design studies reporting AAC intervention outcomes and how these compared to those reported in single-case experimental designs (SCEDs). In addition, we compared the status of intervention features reported in group and SCED studies with respect to instructional strategies utilized. PARTICIPANTS: Participants included school-aged individuals with CCNs who also experienced ASD or ASD with an intellectual delay who utilized aided or unaided AAC. METHOD: A systematic review using descriptive statistics and effect sizes was implemented. RESULTS: Findings revealed that participant features such as race, ethnicity, and home language continue to be underreported in both SCED and group-design studies. Participants in SCED investigations more frequently used multiple communication modes when compared to participants in group studies. The status of pivotal skills such as imitation was sparsely reported in both types of studies. With respect to instructional features, group-design studies were more apt to utilize clinical rather than educational or home settings when compared with SCED studies. In addition, SCED studies were more apt to utilize instructional methods that closely adhered to instructional features more typically characterized as being associated with behavioral approaches. CONCLUSION: The authors discuss future research needs, practice implications, and a more detailed specification of treatment intensity parameters for future research.

A Visual Aid and Objective Rule Encompassing the Data Features of Visual Analysis.

Visual analysis of single-case research is commonly described as a gold standard, but it is often unreliable. Thus, an objective tool for applying visual analysis is necessary, as an alternative to the Conservative Dual Criterion, which presents some drawbacks. The proposed free web-based tool enables assessing change in trend and level between two adjacent phases, while taking data variability into account. The application of the tool results in (a) a dichotomous decision regarding the presence or absence of an immediate effect, a progressive or delayed effect, or an overall effect and (b) a quantification of overlap. The proposal is evaluated by applying it to both real and simulated data, obtaining favorable results. The visual aid and the objective rules are expected to make visual analysis more consistent, but they are not intended as a substitute for the analysts' judgment, as a formal test of statistical significance, or as a tool for assessing social validity.

Participant characteristics predicting communication outcomes in AAC implementation for individuals with ASD and IDD: a systematic review and meta-analysis.

This meta-analysis examined communication outcomes in single-case design studies of augmentative and alternative communication (AAC) interventions and their relationship to participant characteristics. Variables addressed included chronological age, pre-intervention communication mode, productive repertoire, and pre-intervention imitation skills. Investigators identified 114 single-case design studies that implemented AAC interventions with school-aged individuals with autism spectrum disorder and/or intellectual disability. Two complementary effect size indices, Tau(AB) and the log response ratio, were applied to synthesize findings. Both indices showed positive effects on average, but also exhibited a high degree of heterogeneity. Moderator analyses detected few differences in effectiveness when comparing across diagnoses, age, the number and type of communication modes, participant's productive repertoires, and imitation skills to intervention. A PRISMA-compliant abstract is available: https://bit.ly/30BzbLv.

Results reporting in single case experiments and single case meta-analysis.

Single Case Experimental Design is a discipline grounded in applied behavior analysis where the needs of individual clients and the application of scientific inquiry are fundamental tenets. These two principles remain tantamount in the conduct of research using this methodology and the expansion of the method into evidence-based practice determinations. Although recommendations for quality indicators are widespread, implementation is not. Concurrent to the rise of quality indicators is an increasing interest in analysis methodology. Visual analysis has a history of application and validity, newer forms of analysis less so. While some argue for concordance between the two, it may be the differences that are worth exploration in understanding characteristics of trend and variability in much of the published literature. Design choice and visual analysis decisions are rarely fully articulated. Statistical analyses are likewise inadequately justified or described. Recommendations for the explicit language of reporting as derived from prior meta-analysis and a current review of two leading journals provides a scaffold consistent with existing guidelines but additive in detail, exemplars, and justification. This is intended to improve reporting of results for individual studies and their potential use in future meta-analytic work.

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.

Interrater agreement between visual analysts of single-case data: a meta-analysis.

Visual analysis is the most widely applied method of data interpretation for single-case research as it encompasses multifaceted considerations relevant to evaluating behavior change. However, a previous research synthesis found low levels of interrater agreement between visually analyzed ratings of graphed data across all variables under analysis. The purpose of this meta-analysis was to evaluate the peer-reviewed literature to date for potential moderators affecting the proportion of interrater agreement between visual analysts. Nineteen articles with 32 effects were assembled. Potential moderators evaluated included (a) design families, (b) rater expertise, (c) the provision of contextual information for graphs, (d) the use of visual aids, (e) the provision of an operational definition of the construct being rated, and (f) rating scale ranges. Results yielded an overall weighted interrater agreement proportion of .76. Moderator variables identified produced low to adequate levels of interrater agreement. Practical recommendations for future research are discussed.

Incorporating nonoverlap indices with visual analysis for quantifying intervention effectiveness in single-case experimental designs.

The field of neuropsychological rehabilitation frequently employs single case experimental designs (SCED) in research, but few if any, of the published studies use the effect sizes recommended by the American Psychological Association. Among the available methods for analysing single case designs, this paper focuses on nonoverlap methods. This paper provides examples and suggestions for integrating visual and statistical analysis, pointing out where contradictions may occur and how to be a critical consumer.

Reliability of multi-category rating scales.

The use of multi-category scales is increasing for the monitoring of IEP goals, classroom and school rules, and Behavior Improvement Plans (BIPs). Although they require greater inference than traditional data counting, little is known about the inter-rater reliability of these scales. This simulation study examined the performance of nine reliability indices applied to six multi-category scales of different gradations (2, 3, 5, 7, 10, and 15 points) all derived from the same quasi-continuous (1-30) data. The researchers find that each index behaves differently and requires its own interpretation; there is no one-best reliability indices as most indices are scale-dependent. Finally, index values do not remain constant when more categories are collapsed to fewer. New guidelines are needed for optimal methods of obtaining reliability with ordinal scales.

Combining nonoverlap and trend for single-case research: Tau-U.

A new index for analysis of single-case research data was proposed, Tau-U, which combines nonoverlap between phases with trend from within the intervention phase. In addition, it provides the option of controlling undesirable Phase A trend. The derivation of Tau-U from Kendall's Rank Correlation and the Mann-Whitney U test between groups is demonstrated. The equivalence of trend and nonoverlap is also shown, with supportive citations from field leaders. Tau-U calculations are demonstrated for simple AB and ABA designs. Tau-U is then field tested on a sample of 382 published data series. Controlling undesirable Phase A trend caused only a modest change from nonoverlap. The inclusion of Phase B trend yielded more modest results than simple nonoverlap. The Tau-U score distribution did not show the artificial ceiling shown by all other nonoverlap techniques. It performed reasonably well with autocorrelated data. Tau-U shows promise for single-case applications, but further study is desirable.

Effect size in single-case research: a review of nine nonoverlap techniques.

With rapid advances in the analysis of data from single-case research designs, the various behavior-change indices, that is, effect sizes, can be confusing. To reduce this confusion, nine effect-size indices are described and compared. Each of these indices examines data nonoverlap between phases. Similarities and differences, both conceptual and computational, are highlighted. Seven of the nine indices are applied to a sample of 200 published time series data sets, to examine their distributions. A generic meta-analytic method is presented for combining nonoverlap indices across multiple data series within complex designs.

Behaviors that discriminate ADHD in children and adolescents: primary symptoms, symptoms of comorbid conditions, or indicators of functional impairment?

OBJECTIVE: The objectives of this study were to evaluate whether behaviors that differentiate children and adolescents with ADHD from those without are related to the primary diagnostic criteria (i.e., inattention and impulsivity-hyperactivity), symptoms of comorbid conditions, functional impairment, or a combination, and to determine whether behaviors that discriminate are consistent between the key developmental stages of childhood and adolescence. METHOD: Parents and teachers rated children and adolescents with a formal diagnosis of ADHD and those without any mental, physical, or emotional disorders on the multidimensional Behavior Assessment System for Children (2nd ed., BASC-2). RESULTS: Results indicated that behaviors that discriminate children and adolescents with ADHD from those without were associated with primary symptoms, symptoms of comorbid conditions, and indicators of functional impairment. Teachers rated atypicality as the strongest discriminator of children with ADHD from those without and learning problems as the strongest discriminator of adolescents. Parents rated hyperactivity as the strongest discriminator for children and attention problems for adolescents. Activities of daily living was the third strongest discriminator of adolescents as rated by parents. CONCLUSIONS: Findings supported the need for a multidimensional view of ADHD that adds emphasis to issues of functional impairment in routine, daily activities important to success in school and interpersonally. Findings showed that conceptualizing and assessing behaviors demonstrated by children and adolescents with ADHD as a whole instead of only equating a diagnosis of ADHD to hyperactivity, inattention, and impulsivity will establish a foundation for understanding, interpreting, and addressing students' academic and behavioral needs across the home and school.