Between a ROC and a hard place: decision making and making decisions about using the SCQ

BACKGROUND: The Social Communication Questionnaire (SCQ), formerly the Autism Screening Questionnaire (ASQ), is based on a well-validated parent interview, the Autism Diagnostic Interview (ADI). It has shown promise as a screening measure for autism spectrum disorders (ASDs) in a research-referred older sample, though recent studies with younger children reported lower sensitivities when using the suggested cutoff of > or = 15 to differentiate ASDs from children with nonspectrum disorders (NS). METHODS: Diagnostic discrimination of the SCQ was evaluated alone and in combination with the ADOS (Autism Diagnostic Observation Schedule) in a clinical and research-referred sample of 590 children and adolescents (2 to 16 years), with best estimate consensus diagnoses of autism, pervasive developmental disorder, not otherwise specified (PDD-NOS) and non-ASD disorders. The SCQ was completed before the evaluation in most cases. Performance of the SCQ was also compared with the Autism Diagnostic Interview - Revised (ADI-R). RESULTS: Absolute scores and sensitivity in the younger children and specificity for all groups were lower than reported in the original study. Using receiver operating curves (ROC) to examine the area under the curve (AUC), the SCQ was more similar to the ADI-R total score in differentiating ASD from NS disorders in the older (8-10, >11) than younger age groups (<5, 5-7). Lowering the cutoff score in the 2 younger groups improved sensitivity, with specificity remaining relatively low in all groups. Using the SCQ in combination with the ADOS resulted in improved specificity. Diagnostic discrimination was best using the ADI-R and ADOS in combination. CONCLUSIONS: Those interested in using the SCQ should consider adjusting cutoff scores according to age and purpose, and using it in combination with another measure. Sensitivity or specificity may be prioritized for research or screening depending on goals.     

Variability in outcome for children with an ASD diagnosis at age 2

BACKGROUND: Few studies have examined the variability in outcomes of children diagnosed with autism spectrum disorder (ASD) at age 2. Research is needed to understand the children whose symptoms - or diagnoses - change over time. The objectives of this study were to examine the behavioral and diagnostic outcomes of a carefully defined sample of 2-year-old children with ASD, and to identify child and environmental factors that contribute to variability in outcomes at age 4. METHODS: Forty-eight children diagnosed with autism or pervasive developmental disorder not otherwise specified (PDDNOS) at age 2 were followed to age 4. Diagnostic measures included the Autism Diagnostic Observation Schedule - Generic (ADOS-G) and clinical diagnosis at ages 2 and 4, and the ADI-R at age 4. RESULTS: Diagnostic stability for an ASD diagnosis (autism or PDDNOS) was 63%, and for an autism diagnosis was 68%. Children who failed to meet diagnostic criteria for ASD at follow-up were more likely to: 1) be 30 months or younger at initial evaluation; 2) have milder symptoms of autism, particularly in the social domain; and 3) have higher cognitive scores at age 2. No differences between children with stable and unstable diagnoses were found for amount of intervention services received. Among the children with unstable diagnoses, all but one continued to have developmental disorders, most commonly in the area of language. CONCLUSIONS: The stability of ASD was lower in the present study than has been reported previously, a finding largely attributable to children who were diagnosed at 30 months or younger. Implications for clinical practice are discussed.     

Autism spectrum disorder in the second year: stability and change in syndrome expression

OBJECTIVES: Increasing numbers of young children referred for a differential diagnosis of autism spectrum disorders (ASD) necessitates better understanding of the early syndrome expression and the utility of the existing state-of-the art diagnostic methods in this population. METHOD: Out of 31 infants under the age of 2 years referred for a differential diagnosis, 19 were diagnosed with autism, and 9 with pervasive developmental disorder - not otherwise specified (PDD-NOS) when reassessed at 3 years. We examined 1) the symptoms of ASD in the second year and changes in the syndrome expression by the age of three; 2) relationship between expert-assigned clinical diagnosis and diagnostic classification based on Autism Diagnostic Observation Schedule-Generic (ADOS-G) and Autism Diagnostic Interview-Revised (ADI-R) in the second year; 3) the relationship between direct observation and parental report of ASD symptoms. RESULTS: Symptoms of autism and PDD-NOS in the second year were pronounced and stability of the clinical diagnosis was high. The agreement between clinician-assigned autism but not PDD-NOS diagnosis and the ADOS-G was high. However, sensitivity of the ADI-R diagnostic classification of autism was poor. Comparison of concurrent parental report and direct observation revealed discrepancies in severity ratings of key dyadic social behaviors. Changes in communication reflected acquisition of language accompanied by the emergence of unusual language characteristics. Symptoms of social dysfunction were relatively stable over time, and so was the severity of stereotyped behaviors. CONCLUSIONS: The study provides support for stability of clinical diagnosis and syndrome expression in the second year and highlights advantages and limitations of the ADI-R and ADOS-G for diagnosing and documenting symptoms of ASD in infants.     

Autism Spectrum Disorders at 20 and 42 Months of Age: Stability of Clinical and ADI-R Diagnosis

The association between, and stability of, clinical diagnosis and diagnosis derived from the Autism Diagnostic Interview-Revised (ADI-R; Lord, Rutter, & Le Couteur, 1994) was examined in a sample of prospectively identified children with childhood autism and other pervasive developmental disorders assessed at the age of 20 months and 42 months. Clinical diagnosis of autism was stable, with all children diagnosed with childhood autism at age 20 months receiving a diagnosis of childhood autism or a related pervasive developmental disorder (PDD) at age 42 months. Clinical diagnosis of childhood autism was also reasonably sensitive, with all children who went on to receive a clinical diagnosis of childhood autism at 42 months being identified as having autism or PDD at 20 months. However, clinical diagnosis for PDD and Asperger's syndrome lacked sensitivity at 20 months, with several children who subsequently received these diagnoses at 42 months receiving diagnoses of language disorder or general developmental delay, as well as in two cases being considered clinically normal, at the earlier timepoint. The ADI-R was found to have good specificity but poor sensitivity at detecting childhood autism at 20 months; however, the stability of diagnosis from 20 to 42 months was good. In addition, the ADI-R at age 20 months was not sensitive to the detection of related PDDs or Asperger's syndrome. The continuity and discontinuity between behavioural abnormalities identified at both timepoints in the three domains of impairment in autism was examined, both in children who met final clinical criteria for an autistic spectrum disorder, and for children with language disorder who did not, as well as for a small sample of typically developing children.     

The prevalence of autistic spectrum disorders in adolescents with a history of specific language impairment (SLI)

BACKGROUND: Traditionally, autism and specific language impairment (SLI) have been regarded as distinct disorders but, more recently, evidence has been put forward for a closer link between them: a common set of language problems, in particular receptive language difficulties and the existence of intermediate cases including pragmatic language impairment. The present study aimed to examine the prevalence of autism spectrum disorders in a large sample of adolescents with a history of SLI. METHOD: The presence of autism spectrum disorders was examined in seventy-six 14-year-olds with a confirmed history of SLI. A variety of instruments were employed, including the Autism Diagnostic Interview-Revised (ADI-R), the Autism Diagnostic Observation Schedule (ADOS) and the Family History Interview (FHI). RESULTS: The prevalence of autism spectrum disorders in young people with SLI was found to be 3.9%, about 10 times what would be expected from the general population. In addition, a much larger number of young people with a history of SLI showed only some autism spectrum symptoms or showed them in a mild form. CONCLUSIONS: Young people with SLI have an increased risk of autism. The magnitude of this risk is considerable. In addition, a larger proportion (a quarter of individuals) present with a number of behaviours consistent with autism spectrum disorders.     

The effectiveness of Picture Exchange Communication System (PECS) training for teachers of children with autism: a pragmatic, group randomised controlled trial

OBJECTIVE: To assess the effectiveness of expert training and consultancy for teachers of children with autism spectrum disorder in the use of the Picture Exchange Communication System (PECS). METHOD: Design: Group randomised, controlled trial (3 groups: immediate treatment, delayed treatment, no treatment). Participants: 84 elementary school children, mean age 6.8 years. Treatment: A 2-day PECS workshop for teachers plus 6 half-day, school-based training sessions with expert consultants over 5 months. Outcome measures: Rates of: communicative initiations, use of PECS, and speech in the classroom; Autism Diagnostic Observation Schedule-Generic (ADOS-G) domain scores for Communication and Reciprocal Social Interaction; scores on formal language tests. RESULTS: Controlling for baseline age, developmental quotient (DQ) and language; rates of initiations and PECS usage increased significantly immediately post-treatment (Odds Ratio (OR) of being in a higher ordinal rate category 2.72, 95% confidence interval 1.22-6.09, p < .05 and OR 3.90 (95%CI 1.75-8.68), p < .001, respectively). There were no increases in frequency of speech, or improvements in ADOS-G ratings or language test scores. CONCLUSIONS: The results indicate modest effectiveness of PECS teacher training/consultancy. Rates of pupils' initiations and use of symbols in the classroom increased, although there was no evidence of improvement in other areas of communication. Treatment effects were not maintained once active intervention ceased.     

Outcome at 7 years of children diagnosed with autism at age 2: predictive validity of assessments conducted at 2 and 3 years of age and pattern of symptom change over time

OBJECTIVE: To examine the predictive validity of symptom severity, cognitive and language measures taken at ages 2 and 3 years to outcome at age 7 in a sample of children diagnosed with autism at age 2. METHOD: Twenty-six children diagnosed with autism at age 2 were re-assessed at ages 3 and 7 years. At each age symptom severity, cognitive and language assessments were completed. RESULTS: The pattern of autistic symptom severity varied over time by domain. Across time, children moved across diagnostic boundaries both in terms of clinical diagnosis and in terms of instrument diagnosis on the Autism Diagnostic Interview-Revised (ADI-R). On all measures group variability in scores increased with age. Although non-verbal IQ (NVIQ) for the group as a whole was stable across the 3 assessments, this masked considerable individual instability. Standard assessments at age 2 did not predict outcome at age 7 even within the same domain of functioning. In contrast, standard assessments at age 3 did predict outcome. However, a measure of rate of non-verbal communicative acts taken from an interactive play-based assessment at age 2 was significantly associated with language, communication and social outcomes at age 7. CONCLUSIONS: The trajectory of autism symptoms over time differed in different domains, suggesting that they may be, at least in part, separable. Variability in language, NVIQ and symptom severity increased over time. Caution is required when interpreting the findings from assessments of children with autism at age 2 years. At this age measures of rate of non-verbal communication might be more informative than scores on standard psychometric tests. Predictive validity of assessments at age 3 years was greater.     

Development of the Children's Communication Checklist (CCC): A Method for Assessing Qualitative Aspects of Communicative Impairment in Children

The Children's Communication Checklist (CCC) was developed to assess aspects of communicative impairment that are not adequately evaluated by contemporary standardised language tests. These are predominantly pragmatic abnormalities seen in social communication, although other qualitative aspects of speech and language were also included. Some items covering social relationships and restricted interests were incorporated, so that the relationship between pragmatic difficulties and other characteristics of pervasive developmental disorders could be explored. Checklist ratings were obtained for 76 children aged 7 to 9 years, all of whom had received special education for language impairment. In 71 cases, 2 raters (usually a teacher and speech-language therapist) independently completed the checklist, making it possible to establish inter-rater reliability. From an initial pool of 93 items, 70 items, grouped into 9 scales, were retained. Five of the subscales were concerned with pragmatic aspects of communication. A composite pragmatic impairment scale formed from these subscales had inter-rater reliability and internal consistency of around .80. This composite discriminated between children with a school diagnosis of semantic-pragmatic disorder and those with other types of specific language impairment (SLI). The majority of children with pragmatic language impairments did not have any evidence of restricted interests or significant difficulties in the domains of social relationships.     

How useful is the Social Communication Questionnaire in toddlers at risk of autism spectrum disorder?

Background: The Social Communication Questionnaire (SCQ) is a screening instrument with established validity against the Autism Diagnostic Interview‐Revised (ADI‐R) in children aged 4 years and older. Indices of diagnostic accuracy have been shown to be strong in school‐aged samples; however, relatively little is known about the performance of the SCQ in toddlers at risk of autism spectrum disorder (ASD). Methods: This study replicates and extends previous research by Corsello et al. (2007) in a comparatively large (N = 208), substantially younger (20–40 months) sample of children at high risk of ASD. The usefulness of the SCQ as a second‐level screening instrument with different cut‐off scores was evaluated in relation to IQ, age, and type of ASD diagnosis. The use of the SCQ as compared to the ADI‐R was evaluated against clinical diagnosis, both alone and in combination with the ADOS. Results: The SCQ with different cut‐offs consistently showed an unsatisfactory balance between sensitivity and specificity in screening for ASD in high‐risk toddlers, with only a few exceptions for specific age, IQ, or diagnostic groups. Even though the SCQ and ADI‐R were highly correlated, diagnostic agreement with the best evidence clinical diagnosis was poor for both measures. The ADOS used alone consistently had the highest predictive value. For autism versus not‐autism, the combined SCQ and ADOS performed as well as the ADOS alone and notably better than the combination ADI‐R and ADOS. Conclusions: The SCQ is likely to result in a number of false‐positive findings, particularly in children with autism symptomatology, and the balance between sensitivity and specificity is poor. The ADOS should be considered the most valid and reliable diagnostic instrument in these very young at‐risk children.     

Diagnosis of autism spectrum disorders in 2‐year‐olds: a study of community practice

Background: Longitudinal research studies have demonstrated that experienced clinicians using standardized assessment measures can make a reliable diagnosis of autism spectrum disorders (ASDs) in children under age 3. Limited data are available regarding the sensitivity and specificity of these measures in community settings. The aims of this study were to determine how well a standardized diagnostic observational measure (Autism Diagnostic Observation Schedule – ADOS) functions alone, and with a brief parent measure within a community setting when administered by community clinicians. Methods: Clinical records for 138 children between the ages of 24 and 36 months of age who were evaluated for possible ASD or social/language concerns at a hospital‐based developmental evaluation clinic were examined. Evaluations were conducted by community‐based clinical psychologists. Classification results obtained from standardized diagnostic measures were compared with case reviewer diagnosis, by reviewers blind to scores on diagnostic measures, using The Records‐based Methodology for ASD Case Definition that was developed by the Metropolitan Atlanta Developmental Disabilities Surveillance Program. Results: When compared with case review diagnosis, the ADOS demonstrated strong sensitivity and specificity for both Autism versus Not Autism and ASD versus Nonspectrum (NS) diagnoses in this young sample. The Social Communication Questionnaire (SCQ), using the lower cutoff of ≥12, had adequate sensitivity when differentiating Autism from Not Autism, but weak sensitivity when differentiating ASD from NS, missing about 80% of the children with pervasive developmental disorder – not otherwise specified. Using either the Modified Checklist for Autism in Toddlers or the SCQ in combination with the ADOS did not result in improved specificity over the ADOS alone and led to a drop in sensitivity when differentiating ASD from NS disorders. Conclusions: These results demonstrate that following best practice guidelines, the ADOS can be successfully incorporated into clinical practice with relatively good sensitivity and specificity, and worked well with a referred sample of 2‐year‐olds. A parent questionnaire did not lead to any improvement in diagnostic classification above the ADOS used in isolation.     

Office screening and early identification of children with autism

Autism spectrum disorders (ASDs), also called pervasive developmental disorders in the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition, Text Revised), constitute a group of neurodevelopmental disorders that coalesce around a common theme of impairments in social functioning, communication abilities, and repetitive or rigid behaviors. The ASDs considered here include autism/autistic disorder, Asperger disorder/Asperger syndrome (AS), and pervasive developmental disorder not otherwise specified. This article focuses on autism/autistic disorder screening and its early identification, with a brief mention for AS screening, as there are limited tools and no recommendation for universal screening for AS.     

Dosage effects of X and Y chromosomes on language and social functioning in children with supernumerary sex chromosome aneuploidies: implications for idiopathic language impairment and autism spectrum disorders

Background: Supernumerary sex chromosome aneuploidies (X/Y‐aneuploidies), the presence of extra X and/or Y chromosomes, are associated with heightened rates of language impairments and social difficulties. However, no single study has examined different language domains and social functioning in the same sample of children with tri‐, tetra‐, and pentasomy X/Y‐aneuploidy. The current research sought to fill this gap in the literature and to examine dosage effects of X and Y chromosomes on language and social functioning. Methods: Participants included 110 youth with X/Y‐aneuploidies (32 female) and 52 with typical development (25 female) matched on age (mean ～12 years; range 4–22) and maternal education. Participants completed the Wechsler intelligence scales, and parents completed the Children’s Communication Checklist‐2 and the Social Responsiveness Scale to assess language skills and autistic traits, respectively. Results: Both supernumerary X and Y chromosomes were related to depressed structural and pragmatic language skills and increased autistic traits. The addition of a Y chromosome had a disproportionately greater impact on pragmatic language; the addition of one or more X chromosomes had a disproportionately greater impact on structural language. Conclusions: Given that we link extra X chromosomes with structural language impairments and an extra Y chromosome with pragmatic language impairments, X/Y‐aneuploidies may provide clues to genetic mechanisms contributing to idiopathic language impairment and autism spectrum disorders.     

Social communication deficits in conduct disorder: a clinical and community survey

BACKGROUND: Increasing numbers of children are referred to Child and Adolescent Mental Health Services because of disruptive behaviour. Recent reviews on the origins of conduct problems indicate that the most severe and persistent forms are found predominantly among males with a range of neurodevelopmental vulnerabilities, which are likely to have biological substrates. In this study, we tested the hypothesis that many children who are identified with conduct disorder actually have a primary deficit in pragmatic language skills, of a quality and degree that is similar to children on the autistic spectrum. We hypothesised that pragmatic difficulties may underlie the antisocial behaviour in a proportion of children who are labelled as conduct disordered. METHODS: Using the Children's Communication Checklist (Bishop, 1998), we surveyed 142 children who had been referred for clinical investigation, with a predominant diagnosis of either an autistic spectrum condition (n = 87) or conduct disorder (n = 55), and 60 typically developing comparison children. Among children with conduct disorders, males predominated 9:1. RESULTS: On the basis of parent and teacher ratings, two-thirds of those with conduct disorders had pragmatic language impairments and other behavioural features similar in nature and degree to those of children with autism, independent of IQ. In a further study, we surveyed 54 children who had been excluded from elementary schools in a socio-economically disadvantaged inner-London borough and found over two-thirds to have comparable deficits. CONCLUSIONS: These findings have both theoretical and practical implications. First, they indicate the presence of communicative problems in a sub-group of children in whom conduct rather than language had been the major concern. Second, they indicate that severe deficits in pragmatic abilities and autistic-like behaviours can coexist with psychiatric conditions other than autism, especially in boys. Third, they imply that the management of many disruptive children could profitably be addressed to ameliorating their social and communicative skill deficits.     

Loss of language in early development of autism and specific language impairment

Background: Several authors have highlighted areas of overlap in symptoms and impairment among children with autism spectrum disorder (ASD) and children with specific language impairment (SLI). By contrast, loss of language and broadly defined regression have been reported as relatively specific to autism. We compare the incidence of language loss and language progression of children with autism and SLI. Methods: We used two complementary studies: the Special Needs and Autism Project (SNAP) and the Manchester Language Study (MLS) involving children with SLI. This yielded a combined sample of 368 children (305 males and 63 females) assessed in late childhood for autism, history of language loss, epilepsy, language abilities and nonverbal IQ. Results: language loss occurred in just 1% of children with SLI but in 15% of children classified as having autism or autism spectrum disorder. Loss was more common among children with autism rather than milder ASD and is much less frequently reported when language development is delayed. For children who lost language skills before their first phrases, the phrased speech milestone was postponed but long‐term language skills were not significantly lower than children with autism but without loss. For the few who experienced language loss after acquiring phrased speech, subsequent cognitive performance is more uncertain. Conclusions: Language loss is highly specific to ASD. The underlying developmental abnormality may be more prevalent than raw data might suggest, its possible presence being hidden for children whose language development is delayed.     

Difference in age at regression in children with autism with and without Down syndrome

OBJECTIVE: Autism occurs more frequently in individuals with Down syndrome than it does in the general population. Among children with autism and Down syndrome, regression is reported to occur in up to 50%. The aim of this study was to characterize and compare regression in children with autism with and without Down syndrome. METHODS: In this case-control study, children with Down syndrome and autism characterized by a history of developmental regression (n = 12) were compared to children with autism with regression who did not have Down syndrome, matched for chronologic age and gender. Comparisons were made on age at acquisition of language and age at loss of language and other skills as measured by the Autism Diagnostic Interview-Revised (ADI-R). RESULTS: The mean age at acquisition of meaningful use of single words was 40.6 months (SD = 38.0) in children with Down syndrome and autism compared to 14.9 months (SD = 8.5) in children with autism without Down syndrome (p = .005). The mean age at language loss in children with autism with Down syndrome was 61.8 months (SD = 22.9) compared to 19.7 months (SD = 5.8) for those with autism without Down syndrome (p = .01). The mean age at other skill loss was 46.2 months (SD = 19.1) and 19.5 months (SD = 5.6), respectively (p = .006). CONCLUSIONS: When regression occurs in children with autism and Down syndrome it is, on average, much later than is typically seen in children with autism without Down syndrome.     

Children with autistic spectrum disorders. I: comparison of placebo and single dose of human synthetic secretin.

AIMS: To examine the effect of a single dose of human synthetic secretin (HSS) on behaviour and communication in children with autism spectrum disorder (ASD) using an objective measure of communication and social reciprocity and standardised rating scales. METHODS: Randomised, crossover, double blind, and placebo controlled trial of a single intravenous dose of human synthetic secretin (HSS) 2 CU/kg. The 62 subjects (3-8 years) were assigned to group 1 (saline placebo/HSS) or group 2 (HSS/saline placebo). Diagnosis was confirmed by ADI-R (Autism Diagnostic Interview-Revised) algorithm. Severity of symptoms was rated using the CARS (Childhood Autism Rating Scale). Outcome measures included Communication and Symbolic Behavior Scale (CSBS), Ritvo Real-life Rating Scale, weekly Global Rating Scale (GBRS) by parents and teachers, and daily log of gastrointestinal symptoms. The communication subscale of the CSBS, specifying communication function, reciprocity, and social-affective signalling was videotaped and scored by a blinded, trained observer. RESULTS: Sixty one children completed the study. After randomisation, there were no significant differences in gender, race, age, and parent and teacher GBRS and Ritvo Scale between the two groups. Compared with placebo, secretin treatment was not associated with significant improvement of CSBS standard scores from baseline to 2 or 4 weeks post-infusion. Five children showed clinical improvement in standard scores: two after HSS and three after placebo. There were no significant changes in gastrointestinal symptoms after HSS or saline placebo. CONCLUSIONS: A single dose of intravenous human secretin is not effective in changing behaviour and communication in children with ASD when compared to placebo.     

Continuity and change from early childhood to adolescence in autism

BACKGROUND: This longitudinal study of 48 children diagnosed with autism at 2-5 years of age was designed to test the hypothesis that diagnosis would remain stable for most of the sample but that there would be improvements in symptom severity, adaptive behavior, and emotional responsiveness in adolescence. METHODS: A sample of children with autism assessed in both early and middle childhood were observed in late adolescence with the Autism Diagnostic Observation Scale (ADOS) and their parents were administered the Autism Diagnostic Interview-Revised (ADI-R) and the Vineland Adaptive Behavior Scale. RESULTS: All but 2 adolescents (46 of 48) met lifetime criteria for autism according to the ADI-R, and all but 4 adolescents (40 of 44) met criteria for autism spectrum disorder on the ADOS. In contrast to the continuity in diagnosis, parents described improvements in social interactions, repetitive/stereotyped behaviors, adaptive behaviors, and emotional responsiveness to others' distress in adolescence compared to middle childhood. High-functioning adolescents with autism showed more improvement in these domains than low-functioning adolescents with autism. The extent to which the adolescents were observed to be socially engaged with their peers in school in middle childhood predicted adaptive behavior skills even when intelligence level was statistically constrained. CONCLUSIONS: The developmental trajectory of children with autism appears to show both continuity and change. In this sample, most individuals continued to be diagnosed in the autism spectrum but parents reported improvements in adolescence. The results suggest that social involvement with peers improves adaptive behavior skills, and this argues for focusing intervention programs in this area. In addition, it is clear that high-functioning adolescents improve more than low-functioning individuals not only in cognitive abilities but also in social interaction skills. Thus, any early intervention that impacts the cognitive abilities of young children with autism is likely to have a parallel influence on their social skills as they mature into late adolescence and early adulthood.     

Autistic and dysphasic children. I: Clinical characteristics

Autism and dysphasia are behaviorally defined disorders of higher cerebral function which in preschool children share the common core symptom of impairment of language. In this study we describe the clinical characteristics of 314 autistic and 237 dysphasic nonautistic children evaluated by one child neurologist. There was no significant difference between autistic and dysphasic children in gestational age, birth weight, or prevalence of associated medical disorders, all of which were infrequent, although a positive history of resuscitation or ventilatory support was more common in dysphasic than autistic children (P = .03). As a group autistic children are more likely than dysphasic children to have language subtypes affecting central processing and formulation, a family history of psychiatric disorders and autism, and a history of regression of language and behavior. After excluding 12 girls with autistic symptoms who met the clinical criteria for Rett syndrome, we found that there was no significant difference in the number of autistic and dysphasic children with an abnormal sensorimotor examination. Girls with autism were more likely than boys to have severe mental deficiency (38% of autistic girls vs 23% of boys) (P = 0.012) and a motor deficit (27% vs 11%) (P = .0009).     

Evidence for three subtypes of repetitive behavior in autism that differ in familiality and association with other symptoms

Background: Restricted repetitive behaviors (RRBs) are a core feature of autism and consist of a variety of behaviors, ranging from motor stereotypies to complex circumscribed interests. The objective of the current study was to examine the structure of RRBs in autism using relevant items from the Autism Diagnostic Interview‐Revised in a sample of 316 individuals with autistic disorder. Methods/Results: Using exploratory factor analysis, three distinct factors were identified: Repetitive Motor Behaviors (RMB), Insistence on Sameness (IS), and Circumscribed Interests (CI). RMB were found to be associated with a variety of subject characteristics such as IQ, age, social/communication impairments, and the presence of regression. IS was associated with social and communication impairments whereas CI appeared to be independent of subject characteristics, suggesting CI may be particularly useful in subsetting samples. Based on sib‐pair correlations, IS and CI (but not RMB) appear to be familial. Analysis of the data at the case level suggests that the presence of multiple forms of RRB in an individual is associated with more impairment in the social and communication domains, suggesting a more severe presentation of autistic disorder. Conclusions: There appears to be considerable structure within repetitive behavior in autism. The finding that these behaviors are differentially related to subject characteristics and familiality adds to their validity.