The Behavior Observation Scale for autism (BOS): initial results of factor analysis

Diagnostic Assessment of Autism: A Review of Objective Scales

Five objective scales for diagnosis of autism are evaluated with reference to psychometric criteria of reliability (test-retest, interrater, internal consistency) and validity (content, construct, concurrent, discriminant). The five scales are the Diagnostic Checklist for Behavior Disturbed Children (Form E-2), Behavior Observation Scale for Autism, Behavior Rating Instrument for Autistic and Atypical Children, Autism Screening Instrument for Educational Planning, and Childhood Autism Rating Scale. Although all scales have strengths and weaknesses, the Childhood Autism Rating Scale emerges as the strongest scale in terms of demonstrated psychometric properties.

The 'fractionable autism triad': a review of evidence from behavioural, genetic, cognitive and neural research

Autism is diagnosed on the basis of a triad of impairments in social interaction, communication, and flexible imaginative functions (with restricted and repetitive behaviors and interests; RRBIs). There has been a strong presumption that these different features of the syndrome are strongly intertwined and proceed from a common cause at the genetic, cognitive and neural levels. In this review we examine evidence for an alternative approach, considering the triad as largely 'fractionable'. We present evidence from our own twin studies, and review relevant literature on autism and autistic-like traits in other groups. We suggest that largely independent genes may operate on social skills/impairments, communication abilities, and RRBIs, requiring a change in molecular-genetic research approaches. At the cognitive level, we suggest that satisfactory accounts exist for each of the triad domains, but no single unitary account can explain both social and nonsocial features of autism. We discuss the implications of the fractionable-triad approach for both diagnosis and future research directions.

Autistic features in young children with significant cognitive impairment: autism or mental retardation?

This review addresses the issues and challenges related to the differential diagnosis of autism in preschool children with significant cognitive impairment. Issues affecting differential diagnosis include the use of traditional diagnostic guidelines for preschoolers with developmental delays, developmental changes in behavioral characteristics, the involvement of cognitive factors in symptom expression, and the overlap between autism and mental retardation in individuals with significant cognitive impairment. The usefulness of autistic features for differential diagnosis is explored in terms of the core deficits of autism.

[Genetic and clinical diagnosis of infantile autism]

The main objectives of this study were to characterize the selected variables for a better understanding and diagnosis of infantile autism such as clinical and image findings, diagnostic criteria, frequency of neuropsychiatric disorders in the subjects' families, familial recurrence and occurrence of consangunity between the subjects' parents and between other couples in the family. The sample was composed of 36 subjects of both sexes, in the age group from 1 though 20 years old, members of 35 distinctive families, all of which presenting clinical diagnosis for infantile autism. Mental retardation was clinically observed in all subjects of the sample and convulsion in 27.8%; neuropsychiatric disorders were referred in at least one family member of the subjects (97.14% of the families); recurrent autism in 11.42% grandparents and great-grand-parents (2.86%); abnormal findings in computed tomography scan were observed in three subjects. These results support the suggestion of the multifactorial heredity model with differential threshold fold sex in infantile autism. The clinical evaluation of all infantile autism cases should always appraise the neurological, psychiatric and genetic features.

Benchmarks of social treatment for children with autism

Data on the social behavior of typical children may inform practitioners and researchers regarding the appropriate goals of intervention for children with autism. This study assessed the ongoing levels of naturally occurring social behavior in 64 preschool-aged children. A 2 x 2 factorial design was used to analyze population (children with autism and typical children) and age (3 years 3 months vs. 4 years 4 months) differences at the time of preschool entry. Predictable population differences were found for key social behaviors of proximity to children, social bids from children, and focus of engagement on children, as well as for behavioral context variables of verbalizations, adult focus, and atypical behaviors. No differences were found in the amount of time spent focused on toys or objects. There were also no differences in the presenting behaviors of younger and older children with autism. Results are discussed in terms of implications for establishing early social intervention goals.

Early detection of childhood autism: a review of screening instruments and rating scales

The detection and diagnosis of autism may be delayed until middle childhood, 3-4 years after its onset. This is more likely in high-functioning autism and in cases of co-morbidity with mental retardation. Such delays have serious effects on children and their families as well as on the provision of clinical and educational resources. In addition to greater awareness among professionals and to the development of comprehensive services, early detection could be facilitated by screening for early signs and symptoms of autism. The instruments that have been developed to rate autistic behaviours, particularly in pre-school children, are reviewed in this paper. Although the majority of these observational or informant-based measures were not initially designed for screening purposes, previous research findings from their application could be useful in the future development of such a screening instrument. Relevant research findings are discussed and suggestions are made for further evaluation in appropriate populations.

The assessment of individual differences between young children with a pervasive developmental disorder by means of behaviour scales which are derived from direct observation

Data obtained by direct observation of 112 3-6-year-old normal children and 31 children with a pervasive developmental disorder aged 3-6 were used to construct behaviour scales by means of simultaneous component analysis. This is a technique for finding behaviour clusters (components) common to different groups by weighting the variables such that the resulting components maximize variance accounted for when summed over the groups (Milsap & Meredith, 1988, Psychometrika, 53, 123-134; Berge & Kiers, 1990, Nederlands Tijdschrift voor de Psychologie, 45, 221-226). An evaluation of the component structure that was found is given for both groups. Results show uncorrelated components for the normal group, while some of the same components are intercorrelated in the clinical group. Scales were constructed which are shown to have discriminative value with respect to subgroups within the group of patients.

Differentiating pervasive developmental disorder not otherwise specified from autism and language disorders

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.

Diagnostic and assessment issues related to pharmacotherapy for children and adolescents with autism

Autism involves not only developmental delays but also aberrant behavior, both of which change in nature over time. Rating instruments may be useful to assess maladaptive and adaptive behaviors of autistic children in a standardized way and, perhaps, to measure change due to treatment. With the expansion of basic science, knowledge, and technology, there is increasing evidence that autism is etiologically heterogeneous. Currently, there is no biological marker specific to autism, although hyperserotonemia is a consistent finding in one third of autistic children. An aim of basic science research has been to develop a rational pharmacotherapy based upon the underlying neurochemistry. However, at the present time, this approach has not always been successful. It is expected that the development and use of more restrictive criteria, delineation of subtypes of autism, and interaction of descriptive, behavioral, clinical, and basic research will lead to more effective planning for treatment. The relationship of assessment to treatment response is presented and discussed.

An evaluation of the Autism Behavior Checklist

The Autism Behavior Checklist (ABC), an assessment instrument for autistic individuals, was evaluated in a group of 157 subjects, 94 clinically autistic and 63 nonautistic. The two groups differed significantly in ratings of pathology. Both false positive and false negative diagnostic classifications were made when the results of the checklist were compared with clinical diagnosis. Effects of developmental level and age were observed. The ABC appears to have merit as a screening instrument, though results of the checklist alone cannot be taken as establishing a diagnosis of autism. Important issues of reliability and validity remain to be addressed.

The presence or absence of certain behaviors associated with infantile autism in severely retarded autistic and nonautistic retarded children and very young normal children

The modified Behavior Observation Scale adapted from Freeman et al. was used to compare normal, retarded, and autistic children with very low developmental ages and to determine the types of behavior that could differentiate these three diagnostic categories of children. Examination of the data revealed that there was much more overlap between autistic and retarded children than between autistic and normal children. However, a behavioral pattern of autism could be delineated and very retarded autistic children could be distinguished from the nonautistic retarded children. The autistic behavioral pattern included subclusters of symptoms that might be interpreted as disturbances of sensory modulation and motility.