Comparing communication systems for individuals with developmental disabilities: a review of single-case research studies

Are minimally verbal autistic children's modality and form of communication associated with parent responsivity?

Prior work examined how minimally verbal (MV) children with autism used their gestural communication during social interactions. However, interactions are exchanges between social partners. Examining parent-child social interactions is critically important given the influence of parent responsivity on children's communicative development. Specifically, parent responses that are semantically contingent to the child's communication plays an important role in further shaping children's language learning. This study examines whether MV autistic children's (N = 47; 48-95 months; 10 females) modality and form of communication are associated with parent responsivity during an in-home parent-child interaction (PCI). The PCI was collected using natural language sampling methods and coded for child modality and form of communication and parent responses. Findings from Kruskal-Wallis H tests revealed that there was no significant difference in parent semantically contingent responses based on child communication modality (spoken language, gesture, gesture-speech combinations, and AAC) and form of communication (precise vs. imprecise). Findings highlight the importance of examining multiple modalities and forms of communication in MV children with autism to obtain a more comprehensive understanding of their communication abilities; and underscore the inclusion of interactionist models of communication to examine children's input on parent responses in further shaping language learning experiences.

Comparing Interventions With Speech-Generating Devices and Other Augmentative and Alternative Communication Modes: A Meta-Analysis

PURPOSE

Optimal augmentative and alternative communication (AAC) systems for children with complex communication needs depend in part on child characteristics, child preferences, and features of the systems themselves. The purpose of this meta-analysis was to describe and synthesize single case design studies comparing young children's acquisition of communication skills with speech-generating devices (SGDs) and other AAC modes.

METHOD

A systematic search of published and gray literature was conducted. Data related to study details, rigor, participant characteristics, design information, and outcomes were coded for each study. A random effects multilevel meta-analysis was performed using log response ratios as effect sizes.

RESULTS

Nineteen single case experimental design studies with 66 participants (M age = 4.9 years) met inclusion criteria. All but one study featured requesting as the primary dependent variable. Visual analysis and meta-analysis indicated no differences between use of SGDs and picture exchange for children learning to request. Children demonstrated preferences for and learned to request more successfully with SGDs than with manual sign. Children who preferred picture exchange also learned to request more easily with picture exchange than with SGDs.

CONCLUSIONS

Young children with disabilities may be able to request equally well with SGDs and picture exchange systems in structured contexts. More research is needed comparing AAC modes with diverse participants, communication functions, linguistic complexity, and learning contexts.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.22111181.

Preference for Alternative Communication Modality Based on Reinforcer Quality and Availability

Preference for augmentative or alternative communication (AAC) systems has received growing interest in work with individuals with developmental disabilities. An individual may choose a modality based on technological (e.g., auditory-output) or aesthetic features of a system; however, it is ideal that functional features (i.e., effectiveness in producing a reinforcer) affect preference to a much greater extent. Prior research has treated preference as a static variable and may commonly report a lack of preference for a modality or control by irrelevant features of the assessment (e.g., position of the modality in an array). The current study assessed the preference for AAC modalities of a teenager with autism spectrum disorder and intellectual disability using a concurrent-chains procedure. This study extended prior research by including additional methods to ensure accurate assessment of preference (i.e., a control condition) and a reinforcer manipulation to determine whether preference was controlled by non-functional (e.g., aesthetic) or functional (i.e., reinforcer quality and availability) variables. Preference was found to be functionally related to reinforcer availability, including when rapidly alternated between modalities. Moreover, the participant consistently allocated responding away from the control condition. Implications for self-determination and suggestions for future research on preference for AAC systems are considered.

Teaching Preschoolers With Autism to Use Different Speech-Generating Device Display Formats During Play: Intervention and Secondary Factors

Purpose

Children with autism spectrum disorder (ASD) and complex communication needs are increasingly taught to use tablet-based speech-generating devices (SGDs). An important issue in designing such interventions is the selection of an appropriate format for displaying vocabulary. The purpose of this study was to determine (a) whether young children with ASD can be taught to use different SGD vocabulary display formats and (b) whether there are differences across the formats on a range of secondary measures (e.g., preference and generalization).

Method

Five preschoolers with ASD (and prior experience with simpler aided augmentative and alternative communication) were taught to use grid and visual scene display SGDs during a play-based intervention. Acquisition of functional responding was assessed using a single-case experimental design. Secondary variables included error types, antecedents for communication, preference, and generalization.

Results

All participants increased their use of functional target vocabulary using both the grid and the simple visual scene display. Of the five participants, three showed similar performance with both formats, whereas two had slightly higher rates of functional responding with the grid. Individualized differences across participants and formats were apparent across secondary variables (e.g., preference, error types, generalization).

Conclusions

Both simple grid and visual scene displays may be viable options when teaching functional use of SGDs to children with ASD who have prior aided augmentative and alternative communication experience. Analyzing secondary variables beyond device acquisition (e.g., generalization, preference) may have implications for individualizing intervention.

Naturalistic Speech-Generating Device Interventions for Children With Complex Communication Needs: A Systematic Review of Single-Subject Studies

PURPOSE

This article presents a systematic review that aimed to synthesize single-subject-design studies that have examined naturalistic interventions for teaching the expressive use of speech-generating devices (SGDs) to children with complex communication needs. Specifically, this review describes what intervention strategies are most commonly applied in studies with positive effects and minimal methodological flaws and examines the populations and outcomes for which these strategies have been effective.

METHOD

A systematic approach was used to qualitatively code variables of interest to this review. Results were summarized via both visual analysis and effect size methods, and a certainty of evidence methodology was adopted to describe the quality of the evidence.

RESULTS

Thirty-two unique studies met inclusion criteria, with 19 having consistent positive results and meeting minimum requirements for certainty of evidence. Although studies used a variety of titles to describe intervention packages (e.g., milieu teaching, interaction strategies), certain strategies were common across studies. These included (a) creating and capturing communication opportunities via methods such as time delay and questioning; (b) providing feedback via methods such as reinforcement of requests, praise, or expansions; (c) prompting (verbal, physical, gestural); (d) modeling; and (e) training communication partners.

CONCLUSIONS

Findings regarding these intervention components help to provide practical guidelines for naturalistic SGD intervention. Limitations of the current body of research (e.g., need to include more home-based studies and more intermediate to advanced SGDs, need to critically analyze the most critical intervention components) provide suggestions for future research.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.6615332.

Appraisal of comparative single-case experimental designs for instructional interventions with non-reversible target behaviors: Introducing the CSCEDARS ("Cedars")

Evidence-based practice as a process requires the appraisal of research as a critical step. In the field of developmental disabilities, single-case experimental designs (SCEDs) figure prominently as a means for evaluating the effectiveness of non-reversible instructional interventions. Comparative SCEDs contrast two or more instructional interventions to document their relative effectiveness and efficiency. As such, these designs have great potential to inform evidence-based decision-making. To harness this potential, however, interventionists and authors of systematic reviews need tools to appraise the evidence generated by these designs. Our literature review revealed that existing tools do not adequately address the specific methodological considerations of comparative SCEDs that aim to compare instructional interventions of non-reversible target behaviors. The purpose of this paper is to introduce the Comparative Single-Case Experimental Design Rating System (CSCEDARS, "cedars") as a tool for appraising the internal validity of comparative SCEDs of two or more non-reversible instructional interventions. Pertinent literature will be reviewed to establish the need for this tool and to underpin the rationales for individual rating items. Initial reliability information will be provided as well. Finally, directions for instrument validation will be proposed.

Assessing Mand Topography Preference When Developing a Functional Communication Training Intervention

Functional communication training (FCT) is a common function-based behavioral intervention used to decrease problem behavior by teaching an alternative communication response. Therapists often arbitrarily select the topography of the alternative response, which may influence long-term effectiveness of the intervention. Assessing individual mand topography preference may increase treatment effectiveness and promote self-determination in the development of interventions. This study sought to reduce arbitrary selection of FCT mand topography by determining preference during response training and acquisition for two adults with autism who had no functional communication skills. Both participants demonstrated a clear preference for one mand topography during choice probes, and the preferred topography was then reinforced during FCT to reduce problem behavior and increase independent communication. The implications of the results for future research on mand selection during FCT are discussed.

Influences on selection of assistive technology for young children in South Africa: perspectives from rehabilitation professionals

Selection of assistive technology for young children is a complex process. Within a context with limited resources, such as South Africa, research is needed to determine the factors influencing the assistive technology selection process, as these could ultimately either facilitate or hinder the availability and accessibility of affordable, adaptable, acceptable, and high quality assistive technology for this age group.

METHOD

Two asynchronous online focus groups were conducted with 16 rehabilitation professionals to identify the factors they perceived to influence the selection and provision of assistive technology to young children within the South African context.

DATA ANALYSIS

A process of deductive thematic analysis was followed by inductive analysis of the data. Components of the Assistive Technology Device Selection Framework were used as themes to guide the deductive analysis, followed by inductive analysis to create subthemes.

DISCUSSION

The important role of the professional was highlighted in negotiating all the factors to consider in the assistive technology selection and provision process. Adaptation of the Assistive Technology Device Selection Framework is suggested in order to facilitate application to low resourced contexts, such as South Africa. Implications for rehabilitation Assistive technology selection is a complex process with factors pertaining to the users (child and family) of the assistive technology, as well as the rehabilitation professional recommending the assistive technology influencing the process. Although it may be an important factor, the availability of financial resources to purchase assistive technology is not the only determining factor in providing appropriate assistive technology to young children in contexts with limited resources. Formalized support, such as reflective supervision or mentorship programs should be facilitated and utilized by recommending professionals. Home and school visits during assessment ensure a good match between assistive technology and users within the particular context. Facilitating the availability of assistive technology for trial during assessment and/or for a period afterwards will increase the likelihood that appropriate recommendations for assistive technology are made.

Teachers' perceptions of implementation of aided AAC to support expressive communication in South African special schools: a pilot investigation

Although the provision of assistive technology for students with disabilities has been mandated in South African education policy documents, limited data are available on the implementation of aided augmentative and alternative communication (AAC) in classrooms. This pilot investigation used a concurrent mixed-methods survey design to determine the extent to which aided AAC was implemented to foster students' expressive communication in preschool to Grade 3 classrooms in special schools from six urban school districts in the Gauteng (the smallest, most affluent and most densely populated of the nine South African provinces), and also obtained teachers' perceptions of this process. A total of 26 teachers who taught students who used aided AAC for expression participated. Although there is evidence of provision and also implementation of aided AAC in classrooms, various limitations still exist. Teachers identified an array of factors that influenced the implementation of aided AAC, including those related to themselves, the classroom context, the characteristics of aided AAC, students using AAC, and other stakeholders. These factors are discussed in the light of international literature as well as the local context, and are used as a basis to suggest a research agenda for AAC in the South African education system.

Comparing Single Case Design Overlap-Based Effect Size Metrics From Studies Examining Speech Generating Device Interventions

Meaningfully synthesizing single case experimental data from intervention studies comprised of individuals with low incidence conditions and generating effect size estimates remains challenging. Seven effect size metrics were compared for single case design (SCD) data focused on teaching speech generating device use to individuals with intellectual and developmental disabilities (IDD) with moderate to profound levels of impairment. The effect size metrics included percent of data points exceeding the median (PEM), percent of nonoverlapping data (PND), improvement rate difference (IRD), percent of all nonoverlapping data (PAND), Phi, nonoverlap of all pairs (NAP), and Tau(novlap). Results showed that among the seven effect size metrics, PAND, Phi, IRD, and PND were more effective in quantifying intervention effects for the data sample (N = 285 phase or condition contrasts). Results are discussed with respect to issues concerning extracting and calculating effect sizes, visual analysis, and SCD intervention research in IDD.

The role of augmentative and alternative communication for children with autism: current status and future trends

BACKGROUND

Augmentative and alternative communication (AAC) interventions are used for children with autism, often as stand-alone communication interventions for those who are minimally verbal. Our aim was to synthesize the evidence for AAC interventions for children (up to 21 years), and then consider the role of AAC within established, comprehensive, evidence-based autism interventions targeting learning across multiple developmental domains.

DESIGN

We completed a systematic search of three databases (OVID Medline, PsycINFO, ERIC) as well as forward citation and hand searches to identify systematic reviews of AAC intervention efficacy research including children with autism, published between 2000 and March 2016 in peer-reviewed journals. Data pertaining to the quality indicators of included studies, effect sizes for intervention outcomes, and evidence for effectiveness were extracted for descriptive analysis.

RESULTS

The search yielded 17 systematic reviews. Most provided indicators of research quality for included studies, of which only relatively few provided conclusive results. Communication targets tended to be focused on teaching children to make requests. Still, effect size measures for included studies indicated that AAC was effective to highly effective.

CONCLUSION

There is growing evidence for the potential benefits of AAC for children with autism, but there is a need for more well-designed studies and broader, targeted outcomes. Furthermore, a lack of evidence for the role of AAC within comprehensive intervention programs may account for a tendency by autism researchers and practitioners to neglect this intervention. Attempts to compare evidence for AAC with other interventions for children with autism, including those in which the use of AAC is delayed or excluded in pursuit of speech-only communication, must take into account the needs of children with the most significant learning needs. These children pose the greatest challenges to achieving large and consistent intervention effects, yet stand to gain the most from AAC interventions.