The effectiveness of peer modeling with autistic children

Behavioural and developmental interventions for autism spectrum disorder: a clinical systematic review

BACKGROUND

Much controversy exists regarding the clinical efficacy of behavioural and developmental interventions for improving the core symptoms of autism spectrum disorders (ASD). We conducted a systematic review to summarize the evidence on the effectiveness of behavioural and developmental interventions for ASD.

METHODS AND FINDINGS

Comprehensive searches were conducted in 22 electronic databases through May 2007. Further information was obtained through hand searching journals, searching reference lists, databases of theses and dissertations, and contacting experts in the field. Experimental and observational analytic studies were included if they were written in English and reported the efficacy of any behavioural or developmental intervention for individuals with ASD. Two independent reviewers made the final study selection, extracted data, and reached consensus on study quality. Results were summarized descriptively and, where possible, meta-analyses of the study results were conducted. One-hundred-and-one studies at predominantly high risk of bias that reported inconsistent results across various interventions were included in the review. Meta-analyses of three controlled clinical trials showed that Lovaas treatment was superior to special education on measures of adaptive behaviour, communication and interaction, comprehensive language, daily living skills, expressive language, overall intellectual functioning and socialization. High-intensity Lovaas was superior to low-intensity Lovaas on measures of intellectual functioning in two retrospective cohort studies. Pooling the results of two randomized controlled trials favoured developmental approaches based on initiative interaction compared to contingency interaction in the amount of time spent in stereotyped behaviours and distal social behaviour, but the effect sizes were not clinically significant. No statistically significant differences were found for: Lovaas versus special education for non-verbal intellectual functioning; Lovaas versus Developmental Individual-difference relationship-based intervention for communication skills; computer assisted instruction versus no treatment for facial expression recognition; and TEACCH versus standard care for imitation skills and eye-hand integration.

CONCLUSIONS

While this review suggests that Lovaas may improve some core symptoms of ASD compared to special education, these findings are based on pooling of a few, methodologically weak studies with few participants and relatively short-term follow-up. As no definitive behavioural or developmental intervention improves all symptoms for all individuals with ASD, it is recommended that clinical management be guided by individual needs and availability of resources.

Vocal learning in the Grey parrot (Psittacus erithacus): effects of species identity and number of trainers

Grey parrots (Psittacus erithacus) learn referential English labels when they view and interact with 2 humans who model vocal labeling and who demonstrate referentiality and functionality of a label (I.M. Pepperberg, 1990a). To test if both trainers are necessary, the authors contrasted 2-trainer modeling with training by 1 human who presented targeted labels to a bird in concert with appropriate items, who asked questions, and who would reward attempts at the label with the item. The bird was also tutored by either 1 or 2 interactive humans in conjunction with a conspecific who already used referential labels. Referential labels were learned from multiple live tutors but not a single trainer. Presence of a conspecific enhanced learning compared with single-trainer sessions but did not affect acquisition in 2-human sessions. Specific aspects of paired tutoring seem critical for acquiring referential vocal labels.

Proposed use of two-part interactive modeling as a means to increase functional skills in children with a variety of disabilities

PURPOSE

Many behavior modification and intervention programs are based on operant procedures developed for animal subjects, but few use modeling procedures in which one student observes interactions between two proficient trainers. We show how such procedures, which successfully trained Grey parrots (Psittacus erithacus) to produce and comprehend elements of human language, can be adapted for use with children with three types of disabilities: (a) autism with limited social and language skills, (b) developmental delay with physical handicaps and lack of language skills, and (c) hyperactivity with impaired cognitive and social skills.

SUMMARY

Children were evaluated before entering the program and outcomes were recorded to determine improvement levels. No child reached totally normative (physical age-appropriate) levels, but all significantly improved their social and communication skills and use of contextually appropriate behavior.

CONCLUSIONS

A two-trainer modeling system can be a valuable intervention tool for children whose disabilities involve social and communicative skills.