Contingency-based delay to reinforcement following functional communication training for autistic individuals: A multilevel meta-analysis

Functional communication training, an intervention for challenging behavior rooted in principles of applied behavior analysis, has copious empirical support dating back to the mid-1980s for autistic individuals. Recently, there has been a concerted effort to thin reinforcement delivery during functional communication training using contingency-based delays that, in turn, are designed to enhance practicality and feasibility while not compromising on efficacy. In this synthesis, we meta-analyzed the literature using log response ratio effect sizes to investigate (a) combined and across type effectiveness of contingency-based delays and (b) moderating variables that might impact intervention outcomes. Findings showed that contingency-based delays were effective for autistic individuals (log response ratio = −2.17; 95% CI = (−2.76, −1.58)) and most effective when the contingency incorporated positive reinforcement (log response ratio = −2.30; 95% CI = (−2.83, −1.78)). In addition, delay procedures that included differential reinforcement of alternative behavior were overall more effective (log response ratio = −2.13; 95% CI = (−2.72, −1.55)) than those that involved differential reinforcement of other behavior (log response ratio = −1.24; 95% CI = (−3.84, 1.37)). Noteworthy moderating variables found to impact contingency-based delay efficacy included the intervention dosage and the topography of behavior. We discuss these findings and highlight directions where additional empirical research is warranted to improve our understanding about contingency-based delays for autistic individuals. Lay abstract Functional communication training, an intervention for challenging behavior rooted in principles of applied behavior analysis, has copious empirical support dating back to the mid-1980s for autistic individuals. Recently, there has been a concerted effort to thin reinforcement delivery during functional communication training using contingency-based delays that, in turn, are designed to enhance practicality and feasibility while not compromising efficacy. In this synthesis, we meta-analyzed the literature base with the goal of investigating both combined and across type effectiveness of contingency-based delays. We also aimed to investigate moderating variables that might impact intervention outcomes. Findings showed that contingency-based delays were effective for individuals with an autism spectrum disorder diagnosis and most effective when the delay incorporated some form of positive reinforcement. In addition, differential reinforcement of alternative-based delays was overall more effective when compared to differential reinforcement of other behavior-based delays. Noteworthy moderating variables found to impact contingency-based delay efficacy included the intervention dosage and the topography of behavior. We discuss these findings and highlight directions where additional empirical research is warranted to improve our understanding about contingency-based delays for individuals diagnosed with autism spectrum disorder.

Selecting Communicative Interventions Targets for School-Aged participants with ASD and ID: A Single-Case Experimental Design Meta-analysis

Objective: This meta-analysis reviews the literature on communication modes, communicative functions, and types of augmentative and alternative communication (AAC) interventions for school-age participants with autism spectrum disorders and/or intellectual disabilities who experience complex communication needs. Considering potential differences related to outcomes that were targeted for intervention could help identify the most effective means of individualizing AAC interventions. Methods: We performed a systematic literature search using Academic Search Ultimate, ERIC, PsycINFO, Web of Science, and Proquest Dissertations & Theses Global to retrieve research conducted between 1978 and the beginning of 2020. Studies included in the synthesis are (a) in English; (b) has one or more participants with an intellectual delay, developmental disability(ies); (c) reported the results of an augmentative and alternative communication (AAC) intervention to supplement or replace conventional speech for people with complex communication needs; (d) was a SCED; (e) measured social-communicative outcomes. We synthesized results across studies using multi-level meta-analyses of two case-level effect size metrics, Tau and log response ratio. We conducted moderator analyses using meta-regression with robust variance estimation.Results: Across 114 included studies with 330 participants and 767 effect size, overall Tau effects were moderate, Tau = 0.72, 95% CI [0.67, 0.77], and heterogeneous. For the subset of data series where log response ratio could be estimated, the overall average effect was LRR = 1.86, 95% CI [1.58, 2.13], and effects were highly heterogeneous. There were few statistically significant differences found between moderator categories, which included communication mode, communicative function, and type of AAC implemented.Conclusions: This meta-analysis highlights the potential differences related to outcomes that were targeted for AAC interventions for individuals with ASD and IDD. AAC intervention has been shown to improve communication outcomes in this population. However, there was a lack of sufficient data to analyze for some potential moderators such as insufficient descriptive information on participant characteristics. This is likely due to the heterogeneity of the participants and implementation factors; however, these factors were frequently underreported by original study authors which disallowed systematic analysis. That said, there is a need for more detailed participant characteristic descriptions in original research reports to support future aggregation across the literature. Sponsorship: We received funding for the review from the Institute of Education Sciences.Protocol: The review protocol was registered in the PROSPERO system (CRD42018112428).

Participant Characteristics Predicting Communication Outcomes in AAC Implementation for Individuals with ASD and IDD: A Systematic Review and Meta-analysis

This meta-analysis examined social communication outcomes in augmentative and alternative communication (AAC) interventions, or those that involved aided (e.g., speech generating devices, picture point systems) or unaided AAC (e.g., gestures, manual sign language) as a component of intervention, and the extent to which communication outcomes were predicted by participant characteristics. Variables of interest included chronological age, communication mode used prior to intervention, number of words produced and imitation skills of participants prior to intervention. Investigators identified 117 primary studies that implemented AAC interventions with school-aged individuals (up to 22 years) with autism spectrum disorder and/or intellectual disability associated with complex communication needs and assessed social-communication outcomes. All included studies involved single-case experimental designs and met basic study design quality standards. We synthesized findings across studies using two complementary effect size indices, Tau(AB) and the log response ratio, and multi-level meta-analysis with robust variance estimation. With Tau(AB), the overall average effect across 338 participants was 0.72, 95% CI [0.67, 0.76], with a high degree of heterogeneity across studies. With the log response ratio, the overall average effect corresponded to a 538% increase from baseline levels of responding, 95% CI [388%, 733%], with a high degree of heterogeneity across studies and contrasts. Moderator analyses detected few differences in effectiveness when comparing across diagnoses, ages, the number and type of communication modes the participants used prior to intervention, the number of words used by the participants prior to intervention, and imitation use prior to intervention.

Simulation study of estimating between-study variance and overall effect in meta-analyses of log-response-ratio for normal data

Methods for random-effects meta-analysis require an estimate of the between-study variance, $\tau^2$. The performance of estimators of $\tau^2$ (measured by bias and coverage) affects their usefulness in assessing heterogeneity of study-level effects, and also the performance of related estimators of the overall effect. For the effect measure log-response-ratio (LRR, also known as the logarithm of the ratio of means, RoM), we review four point estimators of $\tau^2$ (the popular methods of DerSimonian-Laird (DL), restricted maximum likelihood, and Mandel and Paule (MP), and the less-familiar method of Jackson), four interval estimators for $\tau^2$ (profile likelihood, Q-profile, Biggerstaff and Jackson, and Jackson), five point estimators of the overall effect (the four related to the point estimators of $\tau^2$ and an estimator whose weights use only study-level sample sizes), and seven interval estimators for the overall effect (four based on the point estimators for $\tau^2$, the Hartung-Knapp-Sidik-Jonkman (HKSJ) interval, a modification of HKSJ that uses the MP estimator of $\tau^2$ instead of the DL estimator, and an interval based on the sample-size-weighted estimator). We obtain empirical evidence from extensive simulations of data from normal distributions. Simulations from lognormal distributions are in a separate report Bakbergenuly et al. 2019b.

Vehicle Exposure and Spinal Musculature Fatigue in Military Warfighters: A Meta-Analysis

Context: Spinal musculature fatigue from vehicle exposure may place warfighters at risk for spinal injuries and pain. Research on the relationship between vehicle exposure and spinal musculature fatigue is conflicting. A better understanding of the effect of military duty on musculoskeletal function is needed before sports medicine teams can develop injury-prevention programs. Objective: To determine if the literature supports a definite effect of vehicle exposure on spinal musculature fatigue. Data Sources: We searched the MEDLINE, Military & Government Collection (EBSCO), National Institute for Occupational Safety and Health Technical Information Center, PubMed, and Web of Science databases for articles published between January 1990 and September 2015. Study Selection: To be included, a study required a clear sampling method, preexposure and postexposure assessments of fatigue, a defined objective measurement of fatigue, a defined exposure time, and a study goal of exposing participants to forces related to vehicle exposure. Data Extraction: Sample size, mean preexposure and postexposure measures of fatigue, vehicle type, and exposure time. Data Synthesis: Six studies met the inclusion criteria. We used the Scottish Intercollegiate Guidelines Network algorithm to determine the appropriate tool for quality appraisal of each article. Unweighted random-effects model meta-analyses were conducted, and a natural log response ratio was used as the effect metric. The overall meta-analysis demonstrated that vehicle exposure increased fatigue of the spinal musculature (P = .03; natural log response ratio = −0.22, 95% confidence interval = −0.42, −0.02). Using the spinal region as a moderator, we observed that vehicle ride exposure significantly increased fatigue at the lumbar musculature (P = .02; natural log response ratio = −0.27, 95% confidence interval = −0.50, −0.04) but not at the cervical or thoracic region. Conclusions: Vehicle exposure increased fatigue at the lumbar region.