Giampiero Bartolucci

Reliability and Accuracy of Differentiating Pervasive Developmental Disorder Subtypes

OBJECTIVE To evaluate the ability of the DSM-IV criteria for the pervasive developmental disorders (PDD) to reliably and accurately differentiate PDD subtypes. METHOD The sample consisted of 143 children with various types of developmental disabilities. A diagnosis of PDD and PDD subtype was made by one clinician using information obtained from the Autism Diagnostic Interview-Revised and the Autism Diagnostic Observation Schedule. The raw data from the Autism Diagnostic Interview-Revised, clinical notes (excluding diagnostic opinion), Autism Diagnostic Observation Schedule, IQ, and other available data were independently assessed by three experienced raters, each of whom then made a separate, blind diagnosis. If there was any disagreement, a consensus best-estimate (CBE) diagnosis was made after discussion. To assess reliability, the agreement between the three raters was calculated using k. Accuracy was assessed by calculating the agreement between the clinicians diagnosis and the CBE and by calculating the error rates associated with the three raters using latent class analysis. RESULTS The current DSM-IV criteria show good to excellent reliability for the diagnosis of PDD, Aspergers disorder (AsD), and autism, but they show poor reliability for the diagnosis of atypical autism. The clinician (compared to the CBE) had little difficulty differentiating PDD from non-PDD children and autism from AsD but had more difficulty identifying children with atypical autism. The latent class analysis also showed that the average error rates of the three raters for a differentiation of atypical autism from autism were unacceptably high. CONCLUSIONS Although the psychometric properties of the current DSM-IV criteria for autism and AsD appear quite acceptable, there is likely to be a high rate of misclassification of children given a diagnosis of atypical autism.

The Familial Aggregation of the Lesser Variant in Biological and Nonbiological Relatives of PDD Probands: a Family History Study

OBJECTIVE To determine the risk of the lesser variant (or PDD-like traits) in the biological and nonbiological second- and third-degree relatives of PDD probands using a screening questionnaire and to investigate the extent to which the risk of the lesser variant differs according to various characteristics of the proband. METHOD The sample consists of a series of 34 nuclear families with 2 affected PDD children (multiplex, MPX), 44 families with a single PDD child (simplex, SPX), and 14 families who adopted a PDD child. Data on characteristics of the lesser variant in 1362 biological and 337 nonbiological second- and third-degree relatives were collected from parents by telephone interview and from several maternal and paternal relatives by questionnaire. RESULTS All components of the lesser variant were more common in biological relatives (BR) than nonbiological relatives (NBR), confirming the familial aggregation of the traits. Proband characteristics associated with an increased risk of the lesser variant in relatives were a higher level of functioning and coming from a MPX family. CONCLUSIONS These findings on the familial aggregation of the lesser variant suggest that the genes for PDD also confer susceptibility to the lesser variant and that PDD may be a genetically heterogeneous disorder.

Cohesive discourse in pervasive developmental disorders

Investigated the use of cohesive links to create a reciprocal conversation in individuals with autism, Asperger syndrome, and a control group of children and adolescents with nonspecific social problems. All subjects engaged in a 10-minute conversation with an examiner that touched on various topics. The conversation was audiotaped, transcribed, and coded blindly for several types of cohesive links. Compared to controls, the higher functioning autistic group referred less to a previous stretch of the conversation and more to an aspect of the physical environment. The Asperger group, on the other hand, was very similar to the controls except they made more unclear references that were difficult to interpret. Implications of these findings for understanding the communicative failure of subjects with pervasive developmental disorder are discussed.

Familial Factors Influence Level of Functioning in Pervasive Developmental Disorder

OBJECTIVE To determine whether siblings with pervasive developmental disorders (PDD) tend to have the same type and number of PDD symptoms or a similar level of functioning. METHOD The familial correlations for PDD subtype, symptom totals, adaptive behaviors, and nonverbal IQ were calculated for 94 children with PDD from 46 families. RESULTS On variables measuring PDD symptoms, only impairments in nonverbal communication and verbal/nonverbal status tended to run true within families. There was no familial aggregation of PDD subtype. In contrast, measures of nonverbal IQ and adaptive behaviors in socialization and communication showed a moderate degree of familial resemblance. The degree of familial resemblance did not change if the analysis was restricted only to those families in which both affected children met criteria for autism. CONCLUSION Insofar as the familial resemblance seen in PDD is due to genetic factors, these data provide some evidence that higher- and lower-functioning PDD children may arise from separate genetic mechanisms. Current gene-mapping studies of PDD may need to take this evidence of genetic heterogeneity into account.

Lack of cognitive impairment in first-degree relatives of children with pervasive developmental disorders

OBJECTIVE The objective of this study was to test the hypothesis that mild cognitive impairments aggregate in the unaffected first-degree relatives of probands with autism or pervasive developmental disorders (PDD). METHOD The unaffected siblings and parents of 52 PDD probands and 33 Down syndrome and low birth weight controls were administered a battery of psychometric tests. The tests included measures previously found to be depressed in siblings of autistic children as well as cognitive deficits seen in PDD subjects of normal IQ. In addition, the Vineland Adaptive Behavior Scales were administered to siblings to measure the social-communication impairments found in PDD. RESULTS Neither the siblings nor parents of the PDD probands demonstrated lower cognitive or adaptive behavior scores compared with controls. Developmental histories did not reveal greater rates of social, cognitive, or language delays, nor was there evidence to suggest that relatives of subgroups of PDD probands were different from each other. CONCLUSION These findings indicate that, apart from relatives with PDD, cognitive and social impairments do not aggregate in the families of PDD probands.

A syntactic investigation of verbal autistic, mentally retarded, and normal children

The syndrome of childhood autism is typified by major abnormalities in language development, yet there are few systematic descriptions of autistic children s linguistic systems. We have, therefore, begun a comprehensive investigation of the language of verbal autistic children and concentrate in this paper on comparing the syntax used by 10 verbal autistic children matched for nonlinguistic mental age with a group of mentally retarded subjects and normal controls. Two different means of assessing syntactic development were utilized: Lees Developmental Sentence analysis and Chomskys Transformational analysis. The autistic group was found to rank significantly lower than either the mentally retarded or the normal group in terms of Developmental Sentence Scores. When a transformational grammar was used to describe the language samples of our subjects the autistic children were typified by a higher error rate and lower level of complexity compared to the other two groups. However, the results also indicate that the grammatical system of autistic children is rule-governed and probably not unlike that of young normal or retarded children. In conclusion, it appears that the syntactic abnormalities characteristic of autism are attributable to an extreme delay in language development as well as to an impaired ability to make use of linguistic rules.

High phenotypic correlations among siblings with autism and pervasive developmental disorders

The objective of this study was to examine familial factors influencing clinical variation in sibships that contained at least 2 children affected with autism or another form of pervasive developmental disorder (PDD). The sample included a total of 60 families, 23 with multiple cases of PDD and 37 with a single affected child. Measurements of IQ, adaptive behaviors in socialization and communication, and autistic symptoms were taken on all affected children. A high intraclass correlation, especially on IQ and an index of social behaviors, was observed between affected children from the same family. In contrast, low correlations were observed on measurements of IQ and adaptive behavior between affected and unaffected children from the same family. These data indicate that variation in severity of PDD is influenced by familial, and probably genetic, mechanisms. The results are discussed in relation to current theories on the genetics of autism and the heritable mechanisms underlying variations in clinical severity.

Language and schizophrenia: Towards a synthesis

Abstract This paper proposes a primary deficit that may be a common principal factor in the development of the “schizophrenias.” The way in which this deficit might interact over time with social/developmental variables to produce the classic symptoms of schizophrenic psychosis is discussed as well as the range of behaviors associated with the broader concepts of schizophrenia. The deficit offers a link with a number of etiologic factors. Work is in progress delineating the treatment, rehabilitation and research implications of this hypothesis.