Dennis R. Dixon

Pyrosequencing study of fecal microflora of autistic and control children

There is evidence of genetic predisposition to autism, but the percent of autistic subjects with this background is unknown. It is clear that other factors, such as environmental influences, may play a role in this disease. In the present study, we have examined the fecal microbial flora of 33 subjects with various severities of autism with gastrointestinal symptoms, 7 siblings not showing autistic symptoms (sibling controls) and eight non-sibling control subjects, using the bacterial tag encoded FLX amplicon pyrosequencing (bTEFAP) procedure. The results provide us with information on the microflora of stools of young children and a compelling picture of unique fecal microflora of children with autism with gastrointestinal symptomatology. Differences based upon maximum observed and maximum predicted operational taxonomic units were statistically significant when comparing autistic and control subjects with p-values ranging from <0.001 to 0.009 using both parametric and non-parametric estimators. At the phylum level, Bacteroidetes and Firmicutes showed the most difference between groups of varying severities of autism. Bacteroidetes was found at high levels in the severely autistic group, while Firmicutes were more predominant in the control group. Smaller, but significant, differences also occurred in the Actinobacterium and Proteobacterium phyla. Desulfovibrio species and Bacteroides vulgatus are present in significantly higher numbers in stools of severely autistic children than in controls. If the unique microbial flora is found to be a causative or consequent factor in this type of autism, it may have implications with regard to a specific diagnostic test, its epidemiology, and for treatment and prevention.

A review of research on procedures for teaching safety skills to persons with developmental disabilities

Safety skills are an important but often neglected area of training for persons with developmental disabilities (DD). The present study reviewed the literature on teaching safety skills to persons with DD. Safety skills involve a variety of behaviors such as knowing how to cross the street or what to do in case of a house fire. A number of studies have been conducted on teaching these skills to individuals with DD. The studies reviewed have varying degrees of success and demonstrate varying degrees of generalization, but the general finding has been that prompting, reinforcement, and role-playing are effective teaching procedures across a variety of participants, skills, and settings.

A Brief History of Functional Analysis and Applied Behavior Analysis

The history of functional analysis, as both a concept and a procedure, can be traced back to the earliest days of the discipline of applied behavior analysis (ABA) and even to the earliest days of basic research in behavior analysis that formed the foundation for ABA. Indeed, it is not unreasonable to state that the history of functional analysis is inextricably linked to the history of the discipline of ABA. The general discipline of ABA and the concepts and methods of functional analysis have been built upon the conceptual foundation of operant conditioning, and as advancements have been made in the basic and conceptual arenas of behavior analysis, new refinements have been made in the area of application.

Early Detection of Autism Spectrum Disorders

The US Centers for Disease Control and Prevention (CDC) now estimates that 1 out of every 110 children aged 8 or below have an autism spectrum disorder (ASD; Autism and Developmental Disabilities Monitoring Network, 2009). The CDC has labeled this increase a significant public health concern and with increased prevalence, the need for effective intervention is greater than ever before. The research on treatment of ASD has revealed that early intensive behavioral intervention (EIBI) is highly effective.

THE EFFECTS OF MULTIPLE ExEMPLAR TRAINING ON A WORkING MEMORy TASk INVOLVING SEQUENTIAL RESPONDING IN CHILDREN WITH AUTISM

This study is part of a programmatic line of research into the use of basic positive reinforcement procedures for improving working memory in children with autism spectrum disorders. The authors evaluated the effects of multiple exemplar training, utilizing positive reinforcement, on performance of a “digit span backwards” task—a test of working memory that entails sequential relational responding. All three participants showed improved performance on directly trained stimuli as well as maintenance and generalization to untrained stimuli. The results provide further support for the general hypothesis that performance on working memory tasks is amenable to improvement via behavioral intervention and has implications for treating such tasks as relational operants. Implications for future research and the development of clinical interventions are discussed.

Social Skills in Autism Spectrum Disorders

Autism was first described by Kanner in 1943 and identified as a disorder characterized by impaired development in language and socialization, as well as the presence of repetitive behaviors and restricted interests. The DSM-IV (APA, 2000) currently classifies Autistic Disorder within the Pervasive Developmental Disorders, which also include Asperger’s Disorder, Rett’s Disorder, Childhood Disintegrative Disorder, and PDD-Not Otherwise Specified (PDD-NOS). In recent years, researchers have begun to refer to these disorders as autism spectrum disorders (ASD) due to the continuous nature of symptoms with few clear boundaries upon which to differentiate disorders within the spectrum (Matson & Boisjoli, 2007).

Differential Diagnosis in Autism Spectrum Disorders

While differential diagnosis is typically not one of the primary areas of discussions in ABA, we believe it has particular importance for ASD. The idiosyncratic nature of the disorder and how they affect the nature and type of ABA assessment and treatment cannot be overstated. This chapter will review basic diagnostic methods and their relevance to ABA.

Intensity and Learning Outcomes in the Treatment of Children With Autism Spectrum Disorder.

Ample research has shown that intensive applied behavior analysis (ABA) treatment produces robust outcomes for individuals with autism spectrum disorder (ASD); however, little is known about the relationship between treatment intensity and treatment outcomes. The current study was designed to evaluate this relationship. Participants included 726 children, ages 1.5 to 12 years old, receiving community-based behavioral intervention services. Results indicated a strong relationship between treatment intensity and mastery of learning objectives, where higher treatment intensity predicted greater progress. Specifically, 35% of the variance in mastery of learning objectives was accounted for by treatment hours using standard linear regression, and 60% of variance was accounted for using artificial neural networks. These results add to the existing support for higher intensity treatment for children with ASD.

An evaluation of the effects of intensity and duration on outcomes across treatment domains for children with autism spectrum disorder

Applied behavior analysis (ABA) is considered an effective treatment for individuals with autism spectrum disorder (ASD), and many researchers have further investigated factors associated with treatment outcomes. However, few studies have focused on whether treatment intensity and duration have differential influences on separate skills. The aim of the current study was to investigate how treatment intensity and duration impact learning across different treatment domains, including academic, adaptive, cognitive, executive function, language, motor, play, and social. Separate multiple linear regression analyses were used to evaluate these relationships. Participants included 1468 children with ASD, ages 18 months to 12 years old, M=7.57 years, s.d.=2.37, who were receiving individualized ABA services. The results indicated that treatment intensity and duration were both significant predictors of mastered learning objectives across all eight treatment domains. The academic and language domains showed the strongest response, with effect sizes of 1.68 and 1.85 for treatment intensity and 4.70 and 9.02 for treatment duration, respectively. These findings are consistent with previous research that total dosage of treatment positively influences outcomes. The current study also expands on extant literature by providing a better understanding of the differential impact that these treatment variables have across various treatment domains.

An Application of Neural Networks to Predicting Mastery of Learning Outcomes in the Treatment of Autism Spectrum Disorder

We apply artificial neural networks to the task of predicting the mastery of learning outcomes in response to behavioral therapy for children diagnosed with autism spectrum disorder. We report results for a sample size of 726 children, the largest sample size reported for a study of this nature to date. Our results show that neural networks substantially outperform the linear regression models reported in previous studies, and demonstrate the benefits of leveraging more sophisticated machine learning techniques in the autism research domain.