What is a "placebo controlled" study?
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Biomedical subjects
Publications and source records attributed to F Volkmar.
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OBJECTIVE: To describe the methodological challenges and decisions made in developing a multisite, controlled study of risperidone in children and adolescents with autism. METHODS: Review the design considerations for clinical trials in children with autistic disorder accompanied by severe tantrums, aggressive and/or self-injurious behaviors. These design considerations include the definition of inclusion criteria that are relevant to clinical practice and matching study design to the goal of evaluating short- and long-term effects. Additional ethical and scientific issues concern the length of trial and sample size. RESULTS: We undertook a short-term, placebo-controlled study to evaluate the efficacy and safety of risperidone in children and adolescents with autistic disorder. This trial design was followed by an extended open-label maintenance on risperidone to confirm durability of treatment effects and to monitor safety. Finally, a placebo-controlled discontinuation study tested the need for continuous treatment. CONCLUSIONS: In the absence of standard pharmacological treatment for children with autistic disorder, a placebo-controlled study remains the most appropriate method of testing efficacy and safety. The clinical relevance of this study is enhanced by the addition of an extended maintenance phase followed by a placebo discontinuation.
BACKGROUND: Recognition of individual faces is an integral part of both interpersonal interactions and successful functioning within a social group. Therefore, it is of considerable interest that individuals with autism and related conditions have selective deficits in face recognition (sparing nonface object recognition). METHOD: We used functional magnetic resonance imaging (fMRI) to study face and subordinate-level object perception in 14 high-functioning individuals with autism or Asperger syndrome (the autism group), in comparison with 2 groups of matched normal controls (normal control group ] [NC1] and normal control group 2 [NC2]) (n = 14 for each). Regions of interest (ROIs) were defined in NC1 and then applied in comparisons between NC2 and the autism group. Regions of interest were also defined in NC2 and then applied to comparisons between NC1 and the autism group as a replication study. RESULTS: In the first set of comparisons, we found significant task x group interactions for the size of activation in the right fusiform gyrus (FG) and right inferior temporal gyri (ITG). Post hoc analyses showed that during face (but not object) discrimination, the autism group had significantly greater activation than controls in the right ITG and less activation of the right FG. The replication study showed again that the autism group used the ITG significantly more for processing faces than the control groups, but for these analyses, the effect was now on the left side. Greater ITG activation was the pattern found in both control groups during object processing. CONCLUSIONS: Individuals with autism spectrum disorders demonstrate a pattern of brain activity during face discrimination that is consistent with feature-based strategies that are more typical of nonface object perception.
This study examines possible differences and similarities between social behaviour problems in children with problems classified as pervasive developmental disorder not otherwise specified (PDD-NOS) and a group of children with problems classified as ADHD, as measured by parent questionnaires. The instruments involved were the CBCL (Child Behaviour Checklist), the ABC (Autism Behaviour Checklist) and a new instrument: the CSBQ (Children's Social Behaviour Questionnaire). In comparing the PDD-NOS group and the ADHD group, the results show that, according to parent reports, both groups have severe problems in executing appropriate social behaviour, but the PDD-NOS group can be distinguished from the ADHD group by the nature and the extent of these problems. The PDD-NOS group had significantly more social problems (as measured by the CBCL Social scale), withdrawn problems (as measured by the CBCL Withdrawn scale) and PDD-specific problems (as measured on the ABC Relating scale, the ABC Language scale, the CSBQ total score, the CSBQ Social Interaction scale and CBSQ Communication scale). In addition, although the descriptions of the social problems are global, i.e. on scale level, the results also show that the social problems of PDD-NOS children can be positively formulated and described as at least including severe social interaction problems, withdrawn behaviours and communication problems.
Assessment of autistic disorder (autism) symptoms, primary and secondary, poses more challenging problems than ordinarily found in multisite randomized clinical trial (RCT) assessments. For example, subjects may be uncommunicative and extremely heterogeneous in problem presentation, and current pharmacological treatments are not likely to alter most core features of autism. The Autism Research Units on Pediatric Psychopharmacology (RUPP Autism Network) resolved some of these problems during the design of a risperidone RCT in children/adolescents. The inappropriateness of the usual anchors for a Clinical Global Impression of Severity (CGI-S) was resolved by defining uncomplicated autism without secondary symptoms as a CGI-S of 3, mildly ill. The communication problems, compromising use of the patient as an informant, were addressed by several strategies, including careful questioning of care providers, rating scales, laboratory tests, and physical exams. The broad subject heterogeneity requires outcome measures sensitive to individual change over a wide spectrum of treatment response and side effects. The problems of neuropsychologically testing nonverbal, lower functioning, sometimes noncompliant subjects requires careful instrument selection/adaptation and flexible administration techniques. The problems of assessing low-end IQs, neglected by most standardized test developers, was resolved by an algorithm of test hierarchy. Scarcity of other autism-adapted cognitive and neuropsychological tests and lack of standardization required development of a new, specially adapted battery. Reliability on the Autism Diagnostic Interview (currently the most valid diagnostic instrument) and other clinician instruments required extensive cross-site training (in-person, videotape, and teleconference sessions). Definition of a treatment responder required focus on individually relevant target symptoms, synthesis of possible modest improvements in many domains, and acceptance of attainable though imperfect goals. The assessment strategy developed is implemented in a RCT of risperidone (McDougle et al., 2000) for which the design and other methodological challenges are described elsewhere (Scahill et al., 2000). Some of these problems and solutions are partially shared with RCTs of other treatments and other disorders.
The Children's Social Behavior Questionnaire (CSBQ) contains items referring to behavior problems seen in children with milder variants of PDD. Data of large samples of children diagnosed as having high-functioning autism, PDDNOS, ADHD, and other child-psychiatric disorders were gathered. Besides the CSBQ, parents completed the Autism Behavior Checklist (ABC) and the Child Behavior Checklist (CBCL). The data provided the basis for scale construction of the CSBQ, a comparison of the CSBQ scales with other instruments and a comparison of groups on scores on the CSBQ. The 5 scales obtained referred to Acting-out behaviors, Social Contact problems, Social Insight problems, Anxious/Rigid behaviors and Stereotypical behaviors. Results show that the CSBQ has good psychometric qualities with respect to both reliability and validity. A comparison of the different groups showed that significant group differences were found on all scales. In general, the autism group received the highest scores, followed by the PDDNOS group and the ADHD group. Exceptions were on the Acting-out scale, where the ADHD group scored highest and on the Social Insight scale, where no significant difference was found between the PDDNOS group and the ADHD group. Implications of the results and suggestions for further research are discussed.
Autism and the related pervasive developmental disorders are characterized by patterns of delay and deviance in the development of social, communicative, and cognitive skills, which arise in the first years of life. Although frequently associated with mental retardation, these conditions are distinctive in terms of their course and treatment. These conditions have a wide range of syndrome expression, and their management presents particular challenges for clinicians. Individuals with these conditions can present for clinical care at any point in development. The multiple developmental and behavioral problems associated with these conditions often require the care of multiple providers; coordination of services and advocacy for individuals and their families is important. Early, sustained intervention is indicated, as is the use of various treatment modalities (e.g., pharmacotherapy, special education, speech/communication therapy, and behavior modification).
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This study aimed to explore the boundaries between PDD and related disorders and to develop classificatory algorithms for what is currently called Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS). Data collected by means of a standard coding system for the DSM-IV field trial for autistic disorder were used. Information on diagnostic criteria for autistic disorder as listed in ICD-10 and DSM-IV was compared between subjects functioning at least in the mildly retarded range and clinically classified as autistic disorder (n = 205), PDDNOS (n = 80) and other non-PDD disorders (n = 174). Only a limited number of items from the ICD-10 and DSM-IV systems for autistic disorder significantly discriminated the PDDNOS group from other disorders. A scoring rule based on a short set of 7 ICD-10/DSM-IV criteria with a cutoff of 3 items and 1 social interaction item set as mandatory had the best balance between high sensitivity and high specificity in discriminating PDDNOS from non-PDD disorders. These rules yielded a somewhat better prediction than most effective rules based on the full set of 12 criteria for autistic disorder with a cutoff of 4 items and 1 social item as mandatory. Generally accepted and well-validated criteria to identify individuals with PDDNOS should facilitate both research and clinical services.
This summary provides an overview of the assessment and treatment recommendations contained in the Practice Parameters for the Assessment and Treatment of Children, Adolescents, and Adults With Autism and Other Pervasive Developmental Disorders. The parameters were written to aid clinicians in the assessment and treatment of children and adolescents with autism and other pervasive developmental disorders. Autism and the related pervasive developmental disorders are characterized by patterns of delay and deviance in the development of social, communicative, and cognitive skills, which arise in the first years of life. Although frequently associated with mental retardation, these conditions are distinctive in terms of their course and treatment. These conditions have a wide range of syndrome expression, and their management presents particular challenges for clinicians. Individuals with these conditions can present for clinical care at any point in development. The multiple developmental and behavioral problems associated with these conditions often require the care of multiple providers; coordination of services and advocacy for individuals and their families is important. Early, sustained intervention is indicated, as is the use of various treatment modalities (e.g., pharmacotherapy, special education, speech/communication therapy, and behavior modification.
This article discusses the integration of various aspects of the child's development, particularly the development of language and communication and the way in which these developments interact to enable the child to construct a coherent sense of self. Multiplex developmental disorder is presented as an example of a disorder that affects several of these crucial strands of development. Recent research and controversies regarding the diagnostic descriptions of multiplex and other pervasive developmental disorders are presented. This discussion is used to illustrate the ways in which such disorders affect not only the individual aspects of development, but the child's ability to form a cohesive sense of self. The implications of these difficulties in self-definition for treating children with disorders that affect a variety of aspects of development are also discussed.
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Recent research has yielded increasing support for neurobiologic theories of autism. A number of family and twin studies support the role of genetics and have led to wide acceptance of autism as an organically based disorder. Controversy persists, however, over the role of congenital medical conditions in the etiology of autism. Two rather divergent views have emerged. One, advocated by Gillberg and colleagues, proposes that up to 30% of cases of autism are associated with a known medical condition. On the other hand, research by Rutter and colleagues suggests the incidence may be closer to 10%. In this retrospective study records on 211 subjects with autism and other developmental disorders are reviewed to determine the prevalence of associated medical conditions and its variability related to the system used to diagnose autism. Results suggest the prevalence of medical conditions with suspected etiologic relationship with autism varies between 10 and 15%, depending on the diagnostic system employed. Further variability in prevalence rates results from a less strict definition of "medical condition" and yields rates between 25 and 37%. Disparate findings in previous research may stem from variability in both diagnostic system employed and which medical conditions are considered significant in the etiology of autism.
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OBJECTIVE: To illustrate the use of latent class models for comparing alternative diagnostic criteria for autism. The models are based on the notion that the "true" classification of an individual is unknown but does exist at some unobserved, or "latent," level. Estimates of sensitivity and specificity are obtained for each set of diagnostic criteria through maximum likelihood techniques in relation to the latent standard. METHOD: In this paper, latent class models are used to compare DSM-III, DSM-III-R, and ICD-10 criteria for autism in a sample of 342 individuals with autism or other developmental disabilities. The diagnoses were made by one or more child psychiatrists who evaluated each patient and assigned a diagnosis of autism based on their own expert clinical judgment. In addition, the raters also determined whether criteria were met for the various diagnostic systems. RESULTS: The results indicate that the ICD-10 criteria agree best with the latent standard and a diagnosis based on expert opinion. CONCLUSION: It is suggested that latent class models can be usefully applied to the evaluation of other psychiatric disorders as well and represent an important new tool in evaluating diagnostic criteria by providing a way of dealing with data lacking an observable gold standard.
Features useful in distinguishing children with pervasive developmental disorder (PDD) from those with autism or language disorder were developed from a retrospective chart review using groups of children with PDD-NOS and MA- and sex-matched autistic and language-disordered groups. Charts were reviewed using a list of 80 items compiled from various sources. Items that had adequate interrater reliability and significantly discriminated the PDD-NOS cases from the language-disordered or autistic cases were then evaluated using a second set of cases and signal detection methods. Fewer items significantly discriminated cases with autism from those with PDD-NOS as compared to cases with language disorder. Clinical implications are discussed.
The core clinical feature of autism is a profound disturbance in the emergence of social relations, apparent as early as the very first months of life and almost always by age three years. Many different theories have been proposed to explain this dramatic developmental dysfunction, including cognitive, linguistic, arousal and, most recently, "theory of mind" hypotheses. There is great heterogeneity among autistic individuals and no single explanation captures all the clinical phenomena. Because of the divergent theories and their associated treatment approaches, parents are often burdened by conflicting advice. Field trials and other studies have provided excellent diagnostic criteria for autism for DSM-IV and ICD-10, with high sensitivity and specificity. Careful definition of the clinical phenotype is essential for neurobiological, genetic and behavioral research. While many lines of evidence point to underlying disturbances in brain maturation, no specific CNS dysfunction or biological correlate has been discovered. Rigorous research is not only essential for improving the understanding and treatment of autism; such studies may also help elucidate the normal preconditions for socialization and the pathways that allow a child to enter into the world of human relationships.
The purpose of this article is to present, for the first time, a comprehensive methodology for assessing the reliability of a clinical scale that is frequently utilized in neuropsychological research and in biomedical studies, more generally. The dichotomous-ordinal scale is characterized by a single category of "absence" and two or more ordinalized categories of "presence" of a symptom trait, state, or behavior, and it also has special properties that need to be understood in order for its reliability to be appropriately assessed. Using the Brief Psychiatric Rating Scale (BPRS) as a clinical example, we cover the principles of expressing scale reliability in terms of a dichotomy ("absence" - "presence" of a given BPRS symptom); as a trichotomy ("none"; "mild to moderate" symptomatology; and "severe" symptomatology); and as the full 7-category dichotomous-ordinal scale: "none," "very mild," "mild," "moderate," "moderately severe," "severe," and "extremely severe." Criteria are presented that can be used to evaluate which of these three formats produces the most reliable results. Finally, we address, with a second sample, the important issue of replication, or whether the original reliability findings generalize to other independent populations.