Cases Of Pervasive Developmental Disorders Research Articles

Prevalence and Interpretation of Recent Trends in Rates of Pervasive Developmental Disorders

The aims of this article are to provide an up-to-date review of the methodological features and substantive results of published epidemiological surveys of the prevalence of pervasive developmental disorders (PDD). This article updates previous reviews (1, 2) with the inclusion of new studies made available since then. The specific questions addressed inthis article are: a) how are cases of PDD defined and identified in epidemiological surveys?; b) what are the best estimates for the prevalence of autism and related pervasive developmental disorders considering the methodological implications of the surveys, and c) what interpretation can be given to time trends observed in prevalence rates of PDDs given the hypothesized secular increase in PDDs?

Prevalence and Interpretation of Recent Trends in Rates of Pervasive Developmental Disorders

The aims of this article are to provide an up-to-date review of the methodological features and substantive results of published epidemiological surveys of the prevalence of pervasive developmental disorders (PDD). This article updates previous reviews (1, 2) with the inclusion of new studies made available since then. The specific questions addressed inthis article are: a) how are cases of PDD defined and identified in epidemiological surveys?; b) what are the best estimates for the prevalence of autism and related pervasive developmental disorders considering the methodological implications of the surveys, and c) what interpretation can be given to time trends observed in prevalence rates of PDDs given the hypothesized secular increase in PDDs?

Autism and social anxiety in children with sex chromosome trisomies: an observational study.

Background: Recent studies suggest that an extra sex chromosome increases the risk of both autism and social anxiety, but it unclear whether these risks are specific to particular karyotypes. Methods: We considered diagnostic data from an online psychiatric assessment (DAWBA - The Development and Well-Being Assessment) and questionnaire responses completed by parents of children with 47,XXX (N = 29), 47,XXY (N = 28) and 47,XYY (N = 32) karyotypes. Analysis focused mainly on 54 children who were diagnosed prenatally or on the basis of other medical concerns in childhood (Low Bias subgroup), to minimise ascertainment bias. Results: Children with symptoms of autism who fell short of meeting the Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV criteria were coded as cases of Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS). The odds ratio of autism orPDDNOS in the Low Bias group was computed relative to gender-specific population norms. This gave log odds ratio (95% confidence interval) of 5.56 (4.25 - 6.88) for XXX girls; 4.00 (2.66 - 5.33) for XXY boys; and 4.60 (3.46 - 5.74) for XYY boys. Despite this elevated risk, most children had no autistic features. A diagnosis of DSM-IV Social Phobia was rare, though, in line with prediction, all three Low Bias cases with this diagnosis had 47,XXY karyotype. All three trisomy groups showed increased risk of milder symptoms of social anxiety. Conclusions: An increased risk of autism was found in girls with 47,XXX karyotype, as well as in boys with 47,XXY or 47,XYY. Symptoms of social anxiety were increased in all three karyotypes. There was wide variation in psychiatric status of children with the same karyotype, suggesting that an extra sex chromosome affects developmental stability in a non-specific way, with a diverse range of possible phenotypes.

Autism and social anxiety in children with sex chromosome trisomies: an observational study

Background: Recent studies suggest that an extra sex chromosome increases the risk of both autism and social anxiety, but it unclear whether these risks are specific to particular karyotypes. Methods: We considered diagnostic data from an online psychiatric assessment (DAWBA – The Development and Well-Being Assessment) and questionnaire responses completed by parents of children with 47,XXX (N = 29), 47,XXY (N = 28) and 47,XYY (N = 32) karyotypes. Analysis focused mainly on 54 children who were diagnosed prenatally or on the basis of other medical concerns in childhood (Low Bias subgroup), to minimise ascertainment bias. Results: Children with symptoms of autism who fell short of meeting the Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV criteria were coded as cases of Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS). The odds ratio of autism or PDDNOS in the Low Bias group was computed relative to gender-specific population norms. This gave log odds ratio (95% confidence interval) of 5.56 (4.25 - 6.88) for XXX girls; 4.00 (2.66 - 5.33) for XXY boys; and 4.60 (3.46 - 5.74) for XYY boys. Despite this elevated risk, most children had no autistic features. A diagnosis of DSM-IV Social Phobia was rare, though, in line with prediction, all three Low Bias cases with this diagnosis had 47,XXY karyotype. All three trisomy groups showed increased risk of milder symptoms of social anxiety. Conclusions: An increased risk of autism was found in girls with 47,XXX karyotype, as well as in boys with 47,XXY or 47,XYY. Symptoms of social anxiety were increased in all three karyotypes. There was wide variation in psychiatric status of children with the same karyotype, suggesting that an extra sex chromosome affects developmental stability in a non-specific way, with a diverse range of possible phenotypes.

Autism and social anxiety in children with sex chromosome trisomies: an observational study.

Background: Recent studies suggest that an extra sex chromosome increases the risk of both autism and social anxiety, but it unclear whether these risks are specific to particular karyotypes. Methods: We considered diagnostic data from an online psychiatric assessment (DAWBA - The Development and Well-Being Assessment) and questionnaire responses completed by parents of children with 47,XXX (N = 29), 47,XXY (N = 28) and 47,XYY (N = 32) karyotypes. Analysis focused mainly on 54 children who were diagnosed prenatally or on the basis of other medical concerns in childhood (Low Bias subgroup), to minimise ascertainment bias. Results: Children with symptoms of autism who fell short of meeting the Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV criteria were coded as cases of Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS). The odds ratio of autism orPDDNOS in the Low Bias group was computed relative to gender-specific population norms. This gave log odds ratio (95% confidence interval) of 5.56 (4.25 - 6.88) for XXX girls; 4.00 (2.66 - 5.33) for XXY boys; and 4.60 (3.46 - 5.74) for XYY boys. Despite this elevated risk, most children had no autistic features. A diagnosis of DSM-IV Social Phobia was rare, though, in line with prediction, all three Low Bias cases with this diagnosis had 47,XXY karyotype. All three trisomy groups showed increased risk of milder symptoms of social anxiety. Conclusions: An increased risk of autism was found in girls with 47,XXX karyotype, as well as in boys with 47,XXY or 47,XYY. Symptoms of social anxiety were increased in all three karyotypes. There was wide variation in psychiatric status of children with the same karyotype, suggesting that an extra sex chromosome affects developmental stability in a non-specific way, with a diverse range of possible phenotypes.

Study of pervasive developmental disorders among students in Mosul city

Objective: To detect cases of pervasive developmental disorders among a sample of primary school students in Mosul city. Design and method: A descriptive study including 137 students boys and girls of the second class in Al-Thawra, Al-Ghazali and Abi-Tamam primary schools. A questionnaire paper was used which was filled by the teachers after discussing all the matters with them by the investigator. Rechecking was done and evaluation of the three categories involved in the paper (social interaction difficulties, language defects and conduct disorders). The students were divided into three groups according to the scores on the items of the scales. Group three with high marks in some questions (3, 4) were studied further including any risk factors for their defects, their midyear exam results and their marks in Arabic language. Statistical analysis was done to evaluate the collected data. Results: No case of autism or related disorder was detected. Other problems were detected which were more among males. The commonest problems were being aloof with their own world and excessive fear of noises. Two boys in Al-Thawra school had some conduct disorders and another two had delay in language and speech. Those with language defects had low marks in Arabic language of midyear examination. Conclusion: Problems in social interactions, speech and behavior were important to look for among students which may affect their progress at school.

Prévalence de l’autisme et autres troubles envahissants du développement : données des registres français de population. Générations 1995–2002

Aim and backgroundIn France, prevalence data of pervasive developmental disorders in children are rare despite recently dedicated public health plans aimed to improve the knowledge and types of care of these disorders. Within this context, the two French childhood disabilities registers of Haute-Garonne and Isere counties have been asked to provide recent prevalence data on autism spectrum disorders. MethodsThese two population-based registers record all the cases of pervasive developmental disorders in children residing in covered counties in their eighth year of life, after parental approval. Data are actively collected from the medical records available in various data sources. The main data source is the “county house for people with disabilities” i.e. the local authority which determines the orientation for special education and the decision of special allocation for disabled children. Other data sources are “autism resource centres” and psychiatric hospitals. Diagnoses were coded according to the International Classification of Disease (ICD 10). For this analyze, diagnoses selected were typical and atypical autism (F84.0 and F84.1), Asperger disorder (F84.5), other pervasive developmental disorders (F84.8) and pervasive developmental disorders not otherwise specified (F84.9). The data presented here concerned children born between 1995 and 2002. Prevalence rates were calculated for 10 000 children living in their eighth year of life in each counties. ResultsThe overall prevalence rate in the eighth year of life over the whole study period was 31.9 per 10,000 children in Haute-Garonne and 34.9 per 10,000 in Isere, with a significant increasing trend between 1995 and 2002 in Haute-Garonne county. The sex-ratio was 3.8 and 3.5 respectively in Haute-Garonne and Isere. In both counties, about half of the children had an associated intellectual deficiency and about one third if only severe impairment (defined by an IQ below 50) was considered. An epilepsy was more often present when an intellectual deficiency was associated. ConclusionData from the two French registers were quite comparable and demonstrated that prevalence rates of pervasive developmental disorders in the eighth year of life were in the lower range of those published in the international literature.

A consideration of adolescent cases of pervasive developmental disorders visiting a psychiatric clinic

A consideration of adolescent cases of pervasive developmental disorders visiting a psychiatric clinic

Instrument to screen cases of pervasive developmental disorder: a preliminary indication of validity

To translate into Portuguese, back-translate, culturally adapt and validate a screening instrument for pervasive developmental disorder, the Autism Screening Questionnaire, for use in Brazil. A sample of 120 patients was selected based on three groups of 40: patients with a clinical diagnosis of pervasive developmental disorder, Down syndrome, or other psychiatric disorders. The self-administered questionnaire was applied to the patients' legal guardians. Psychometric measures of the final version of the translated questionnaire were tested. The score of 15 had sensitivity of 92.5% and specificity of 95.5% as a cut-off point for the diagnosis of pervasive developmental disorder. Internal validity for a total of 40 questions was 0.895 for alpha and 0.896 for KR-20, ranging from 0.6 to 0.8 for both coefficients. Test and retest reliability values showed strong agreement for most questions. The final version of this instrument, translated into Portuguese and adapted to the Brazilian culture, had satisfactory measurement properties, suggesting preliminary validation proprieties. It was an easy-to-apply, useful tool for the diagnostic screening of individuals with pervasive developmental disorder.

Sur la prévalence de l’autisme et des troubles envahissants du développement (TED)

Estimates of the prevalence of autism and pervasive developmental disorders (PDD) are discordant and are moving towards an apparent increase in rates. The studies carried out since 1966 illustrate the variability of the protocols used and explanatory hypotheses put forward. These investigations are difficult, sparse, but still growing at the same time that a debate develops on the possible increase in actual prevalence. Indeed, the rate initially admitted for classic autism was 5/10,000, then 1/1000 with an expanded definition to the forms, but the current figures are very different (almost 0.7% for all PDD), and this increase raises questions. The arguments in favour of an apparent increase are primarily methodological. Several biases are encountered when one compares the recent publications with those of previous years. First, autism is better known and recognized than 30 or 40 years ago. Then, the diagnostic criteria used over time are changing variables, and comparisons difficult. Recent studies using the criteria of a broader definition of autism, polyhandicap with severe retardation and autism signs of lighter forms. The fact that children with autism are diagnosed more frequently in the younger age could also occasionally lead to an artificial increase in the number of cases identified in new surveys in populations of young children. Other factors are cited to explain the current increase. There could be higher rates of autism (and mental retardation) among children of migrants from distant countries, with the aetiological hypothesis of maternal infections, more frequent due to immune deficiency against infectious agents depending on the environment, metabolic decompensations also related to changes in surroundings, or more births from unions among migrant mothers and men with Asperger syndrome (with increased risk of paternity of a child with autism). Other theories relate to pollution, vaccinations, a growing number of premature babies; all assumptions that appear, for the time being, insufficiently explored and documented. The issue is also one of the motivations underlying these steps, and setting a parallel prevalence actually increased with this or that factor has presently been scientifically validated. Finally, if a careful reading of recent publications indicates that autism has become more frequent; assumptions that describe an increase in "artificial", based on methodological arguments, seem to be more consistent. EFFECTS OF EXTENSION OF DIAGNOSTIC CRITERIA AND NOSOGRAPHY FOR PDD: Today, the recruitment of individuals with autism in a population far exceeds the initial criteria of Kanner in the 1970's. It includes clinical forms with associated pathologies, or lighter and probably more frequent clinical forms. Other assumptions arouse interest, but also controversy regarding their relevance. The enumeration of cases of PDD in a population is actually at its beginning. In the 1970's, "childhood psychoses" (the term then used) seemed rare. The identification of cases was probably the main reason. Long available figures remain scarce, and their rate increases gradually from the 1990s, but is, in fact, a problem of inflation. What is the part played in this flight of changing diagnostic criteria and substitutions, or other methodological effects? Or even opportunistic effects, if we speak of an epidemic to undermine a variety of factors. The evidence provided so far is the improved identification of cases, enlargement of the concept, and better shared diagnostic criteria. However, the validity and limitations of clinical forms are still vague and unresolved. How to study epidemiology in the future - to move forward, studies should be designed with partners' medical history and medicosocial studies, based on a better consensual methodology, epidemiology, statistics and diagnosis, with a definition of the thresholds for inclusion, and arbitration procedures. On this basis, a study must also be coordinated with those concerning mental retardation, learning disorders, etc, otherwise the same topics will be counted twice or even three times. As for the addition of syndromic forms of PDD (those with known aetiology), their number is still below a proportion sufficient to be an appeal. Moreover, another problem exists: the degree of membership of each of these syndromes, or individual cases, or autistic spectrum disorders (internal variability phenotypes). For the moment, we could design two studies included better: developmental disorders and associated pathologies. Regarding the "ethic" dimension, a more regular diagnosis of PDD (preferred to that of mental retardation or learning disorder) will lead to shared practices and set limits for greater recognition.

A Preliminary Study on Screening Prevalence of Pervasive Developmental Disorder in Schoolchildren in Iran

To study prevalence rates of pervasive developmental disorder (PDD) symptoms and differences between subtypes in school age Iranian children. A random sample of 2,000 school age children from both genders was selected. A parent-completed, DSM-IV-referenced rating scale of PDD symptoms was used. About 1.9% of the sample obtained screening cutoff scores for probable autistic disorder and 0.5 for probable asperger's disorder. The rate of probable PDD was not more in girls than the boys. The rate of suspected cases of PDD in Iran is very high and probable autistic disorder is not gender related. It shows the need for more consideration of PDD in the mental health programs planning.

Brief Report: Pervasive Developmental Disorder Can Evolve into ADHD: Case Illustrations

Despite prominent attentional symptoms in Pervasive Developmental Disorders (PDD) the relationship between PDD and Attention Deficit Hyperactivity Disorder (ADHD) has received little direct examination. In addition, outcome studies of children with PDD often focus on language, educational placement, or adaptive skills, but seldom on loss of the PDD diagnosis or change to another clinical syndrome. We present three cases in detail, and tabular data on eight more, that illustrate a clinical presentation in which prototypical cases of PDD evolve into clear-cut cases of ADHD from early to middle childhood.

No effect of MMR withdrawal on the incidence of autism: a total population study

A causal relationship between the measles, mumps, and rubella (MMR) vaccine and occurrence of autism spectrum disorders (ASD) has been claimed, based on an increase in ASD in the USA and the UK after introduction of the MMR vaccine. However, the possibility that this increase is coincidental has not been eliminated. The unique circumstances of a Japanese MMR vaccination program provide an opportunity for comparison of ASD incidence before and after termination of the program. This study examined cumulative incidence of ASD up to age seven for children born from 1988 to 1996 in Kohoku Ward (population approximately 300,000), Yokohama, Japan. ASD cases included all cases of pervasive developmental disorders according to ICD-10 guidelines. The MMR vaccination rate in the city of Yokohama declined significantly in the birth cohorts of years 1988 through 1992, and not a single vaccination was administered in 1993 or thereafter. In contrast, cumulative incidence of ASD up to age seven increased significantly in the birth cohorts of years 1988 through 1996 and most notably rose dramatically beginning with the birth cohort of 1993. The significance of this finding is that MMR vaccination is most unlikely to be a main cause of ASD, that it cannot explain the rise over time in the incidence of ASD, and that withdrawal of MMR in countries where it is still being used cannot be expected to lead to a reduction in the incidence of ASD.

Does routine child health surveillance contribute to the early detection of children with pervasive developmental disorders? – An epidemiological study in Kent, UK

. Tebreugge, M., Nandini, V. & Ritchie, J. ( 2004 ) 4 : . Available at: http://www.biomedcentral.com/1471‐2431/4/4 Background Recently changed guidelines for child health surveillance in the UK suggest targeted checks only, instead of the previously conducted routine or universal screening at 2 years and 3.5 years. There are concerns that these changes could lead to a delay in the detection of children with autism and other pervasive developmental disorders (PDD). Recent UK studies have suggested that the prevalence of PDD is much higher than previously estimated. This study establishes to which extent the routine checks contributed to the early detection and assessment of cases of PDD. Simultaneously we have evaluated the process involved and estimate the prevalence of PDD in our district.Methods Retrospective study design utilizing community medical files. Headteachers of schools (n = 75) within Maidstone district (Kent) were asked to report all children with an established diagnosis of autism or PDD attending year 4 (born in 1991 and 1992; n = 2536) in October 2000 based on educational records.Results Fifty‐nine schools (78.7%) took part in the study. A total of 33 children were reported. Twenty‐one fulfilled the inclusion criteria (12 falsely reported). The prevalences were (per 10 000): PDD 82.8 (male to female ratio 6 : 1), childhood autism 23.7, Asperger's syndrome 11.8 and autistic spectrum disorder 47.3. Coexisting medical conditions were noted in 14.3%; 52.4% were attending mainstream schools. In 63.2% of cases concerns – mainly in the area of speech and language development (SLD) – had been documented at the 2 years check. At the 3.5 years check concerns were noted in 94.1%– the main area was again SLD (76.5%), although behavioural abnormalities were becoming more frequent (47.1%). A total of 13 children (68.4%) were referred for further assessment as a direct result of the checks.Conclusions The prevalences for different types of PDD were similar to those published recently, but much higher than reported a few years ago. Analysis of our data suggests that routine surveillance is a valuable contributing factor for the early detection of PDD and thereby facilitates early intervention. Thus, if routine surveillance ceases, then an alternative method of early detection should be put in place.

Does routine child health surveillance contribute to the early detection of children with pervasive developmental disorders? An epidemiological study in Kent, U.K.

BackgroundRecently changed guidelines for child health surveillance in the United Kingdom (U.K.) suggest targeted checks only, instead of the previously conducted routine or universal screening at 2 years and 3.5 years. There are concerns that these changes could lead to a delay in the detection of children with autism and other pervasive developmental disorders (PDD). Recent U.K. studies have suggested that the prevalence of PDD is much higher than previously estimated. This study establishes to which extent the routine checks contributed to the early detection and assessment of cases of PDD. Simultaneously we have evaluated the process involved and estimate the prevalence of PDD in our district.MethodsRetrospective study design utilising community medical files. Headteachers of schools (n = 75) within Maidstone district (Kent) were asked to report all children with an established diagnosis of autism or PDD attending year 4 (born '91 and '92 / n = 2536) in October 2000 based on educational records.Results59 schools (78.7%) took part in the study. A total of 33 children were reported. 21 fulfilled the inclusion criteria (12 falsely reported). The prevalences were (per 10,000): PDD 82.8 (male to female ratio 6:1), childhood autism 23.7, Asperger's syndrome 11.8 and autistic spectrum disorder 47.3. Co-existing medical conditions were noted in 14.3%; 52.4% were attending mainstream schools. In 63.2% of cases concerns – mainly in the area of speech and language development (SLD) – had been documented at the 2 year check. At the 3.5 year check concerns were noted in 94.1% – the main area was again SLD (76.5%), although behavioural abnormalities were becoming more frequent (47.1%). A total of 13 children (68.4%) were referred for further assessment as a direct result of the checks.ConclusionsThe prevalences for different types of PDD were similar to figures published recently, but much higher than reported a few years ago. Analysis of our data suggests that routine surveillance is a valuable contributing factor for the early detection of PDD and thereby facilitates early intervention. Thus, if routine surveillance ceases, then an alternative method of early detection should be put in place.

A Screening Instrument for Autism at 18 Months of Age: A 6-Year Follow-up Study

A population of 16,235 children aged 18 months was screened using the Checklist for Autism in Toddlers (CHAT) to identify childhood autism (CA). Two further screening procedures were conducted at age 3 and 5 years. The population was followed up at age 7 years in order to establish the sensitivity, specificity, and positive predictive value of the instrument. A brief checklist assessing joint attention and pretend play behaviors was administered by primary health care practitioners when the children were 18 months old. Follow-up methods included screening through parents and health practitioners and checking medical and educational records. Nineteen cases of CA were successfully identified by the CHAT at 18 months. At follow-up a total of 50 cases of CA were identified via all surveillance methods. Thus, the CHAT has a sensitivity of 38% and a specificity of 98% for identifying CA. The positive predictive value of the instrument was maximized by concentration on the highest-risk group. Repeated screening 1 month later increased the positive predictive value to 75% for identification of CA but reduced the sensitivity to 20%, although the specificity was close to 100%. The screen also identified cases of pervasive developmental disorder as well as children with language and other developmental disorders. The CHAT can be used to identify cases of autism and related pervasive developmental disorders at 18 months of age. It is emphasized that the CHAT is not a diagnostic instrument but can identify potential cases of autism spectrum disorders for a full diagnostic assessment.

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.

Parents and collateral relatives of children with pervasive developmental disorders: a family history study.

The objective of this study was to see whether, using the family history method, the risk for pervasive developmental disorder (PDD), cognitive impairments, and other psychiatric symptoms is greater in the parents and collateral relatives of probands with PDD compared to a control group. A semistructured family history interview was carried out with the parents of 52 probands with PDD and 33 parents of controls. Rates of cognitive impairments and psychiatric problems were not found more frequently in parents or relatives of PDD probands compared to relatives of controls, but four cases of PDD were reported among the extended families of the PDD probands. The relatives with PDD were related to the probands through the maternal line, possibly suggesting some form of maternal influence on inheritance or reduced penetrance in females with the PDD genotype.

Clinical and genetic relationships between autism‐pervasive developmental disorder and Tourette syndrome: A study of 19 cases

Children with autism or pervasive developmental disorder (PDD) and Tourette syndrome (TS) share a number of symptoms. Forty-one cases have been reported in which PDD patients subsequently developed TS. We term this PDD----TS. We describe an additional 16 such patients plus 3 families where a close relative of a TS proband had autism. There was a high frequency of alcoholism, drug abuse, obsessive-compulsive, and other behavior disorders in the relatives of these patients. This frequency was virtually identical to that observed in relatives of individuals with TS only. We suggest there is an intimate genetic, neuropathologic relatedness between some cases of PDD and TS. Many observations have led us to suggest that the genetic defect in TS may be a mutation of tryptophan oxygenase and that TS is inherited as a semidominant semirecessive trait, i.e., homozygosity for a common gene which shows some expression in the heterozygous state. We propose that some types of PDD are inherited in the same fashion and by the same gene. This would explain the similarity of symptoms, frequent evolution of PDD into TS, the apparent recessive inheritance of PDD despite no increase in consanguinity, the high frequency of behavior problems in the relatives of PDD----TS patients and the serotonin abnormalities.