Is there a 'regressive phenotype' of Autism Spectrum Disorder associated with the measles-mumps-rubella vaccine? A CPEA Study

Developmental regression in children: Current and future directions

Developmental regression describes when a child loses previously established skills, such as the ability to speak words and is most recognised in neurodevelopmental conditions including Autism; Developmental Epileptic Encephalopathies, such as Landau Kleffner syndrome, and genetic conditions such as Rett syndrome and Phelan McDermid syndrome. Although studies have reported developmental regression for over 100 years, there remain significant knowledge gaps within and between conditions that feature developmental regression. The certainty of evidence from earlier work has been limited by condition-specific studies, retrospective methodology, and inconsistency in the definitions and measures used for classification. Given prior limitations in the field, there is a paucity of knowledge about neurocognitive mechanisms, trajectories and outcomes for children with developmental regression, and their families. Here we provide a comprehensive overview, synthesise key definitions, clinical measures, and aetiological clues associated with developmental regression and discuss impacts on caregiver physical and mental health to clarify challenges and highlight future directions in the field.

Understanding the Relationship between Distress Behaviour and Health Status of People with Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is associated with complex distress and challenging behaviours that have a negative impact on the everyday life of those with ASD, as well as their parents and carers. These challenging behaviours include negative emotional behaviours, motor behaviours, and changes in routines. Even though challenging behaviours occur in most subjects with ASD, the cause of these largely remains unknown. It has been implicated that these challenging behaviours are associated with a change in the health of those with ASD. More research needs to be conducted that can establish a direct association. Towards this goal, the present study aimed to explore whether health status had an impact on the distressing behaviour in the subjects diagnosed with ASD. We analysed the response from the parents/carers in a Macedonian population of those with ASD, to determine which challenging behaviours were most likely to be observed during a change in health. Based on a scoring system, the manifestation of challenging behaviour was evaluated and compared with the changes in health. Changes in appetite or dietary preferences, irritability and low mood, and loss of previously acquired skills had the greatest association with a change in health. These findings provide early insight into types of challenging behaviours that are directly associated with a change in health. Our results demonstrate a relationship between health status and challenging behaviour in the subject with autism, suggesting that caregivers may need to consider this when choosing strategies for managing challenging behaviour.

Children with ASD and Communication Regression: Examining Pre-Loss Skills and Later Language Outcomes Through the Preschool Years

This study investigated receptive and expressive language outcomes in children with autism spectrum disorder (ASD) with and without a history of language/communication regression, employing three progressively less stringent definitions of regression. Data were derived from a large, longitudinal sample of children with ASD in which regression was assessed at approximately 30 months. Results indicated poorer receptive language and larger discrepancies between receptive and expressive language in the regression group than the group without regression at 44 months but not 66 months. Number of words used before loss predicted receptive language at 44 months. Overall, results suggest that a regression profile in ASD is associated with modest and transient impacts on language outcomes that are no longer discernable at school entry.

Bayonet-shaped language development in autism with regression: a retrospective study

Background

Language delay is one of the major referral criteria for an autism evaluation. Once an autism spectrum diagnosis is established, the language prognosis is among the main parental concerns. Early language regression (ELR) is observed by 10–50% of parents but its relevance to late language level and socio-communicative ability is uncertain. This study aimed to establish the predictive value of ELR on the progression of language development and socio-communicative outcomes to guide clinicians in addressing parents’ concerns at the time of diagnosis.

Methods

We used socio-communicative, language, and cognitive data of 2,047 autism spectrum participants from the Simons Simplex Collection, aged 4–18 years (mean = 9 years; SD = 3.6). Cox proportional hazard and logistic regression models were used to evaluate the effect of ELR on language milestones and the probability of using complex and flexible language, as defined by the choice of ADOS module at enrollment. Linear models were then used to evaluate the relationship of ELR and non-verbal IQ with socio-communicative and language levels.

Results

ELR is associated with earlier language milestones but delayed attainment of fluent, complex, and flexible language. However, this language outcome can be expected for almost all autistic children without intellectual disability at 18 years of age. It is mostly influenced by non-verbal IQ, not ELR. The language and socio-communicative level of participants with flexible language, as measured by the Vineland and ADOS socio-communicative subscales, was not affected by ELR.

Limitations

This study is based on a relatively coarse measure of ultimate language level and relies on retrospective reporting of early language milestones and ELR. It does not prospectively document the age at which language catches up, the relationship between ELR and other behavioral areas of regression, nor the effects of intervention.

Conclusions

For autistic individuals with ELR and a normal level of non-verbal intelligence, language development follows a “bayonet shape” trajectory: early first words followed by regression, a plateau with limited progress, and then language catch up.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13229-021-00444-8.

Prevalence and Age of Onset of Regression in Children with Autism Spectrum Disorder: A Systematic Review and Meta-analytical Update

A systematic review published in 2013 reported 32% of children on the autism spectrum experience skill loss, known as autistic regression. However, the frequency varied depending on definition and measures used to capture skills. Retrospective parent report and prospective observation indicate loss of language and/or social skills, with motor skills typically unaffected. Our aim was to update the prevalence and age of onset of autistic regression through a meta-analysis of the literature to understand if there have been changes to the reported onset and prevalence since 2010. A systematic literature search was conducted using Medline, Embase, PsycINFO, and the Cochrane Library databases and included studies published from 2010 onward. Risk of bias assessment was performed on included studies. A random effects model was used to calculate the pooled prevalence and age of onset of autistic regression. Ninety-seven studies were included in the systematic review, of which 75 studies involving 33,014 participants had sufficient data for meta-analytic syntheses. The pooled proportion of autistic regression was 30% (95% confidence interval [CI]: 27-32%) but heterogeneity was high (I² = 96.91) and did not reduce with sensitivity or subgroup analyses based on study design or clinical differences, respectively. Prevalence varied according to risk of bias (low: 27%) and definition of regression (language: 20%, language/social: 40%, mixed: 30%, and unspecified: 27%). Weighted average age of onset was 19.8 months. Findings from this meta-analysis highlight the importance of developing a standardized definition of autistic regression, and tools to measure this at multiple time points during early childhood development. LAY SUMMARY: About a third of children with Autism Spectrum Disorder experience loss of skills, which is also known as autistic regression. This paper provides an update of the rate of autistic regression in children and the age when they first experience loss of skills, based on current studies. The findings from this review contribute to our understanding of the onset patterns of autistic regression. Unfortunately, studies are not sufficiently similar, making it difficult to provide clear answers on the exact timing or type of regression seen in different children.

Immunized against science: Narrative community building among vaccine refusing/hesitant parents

Recent outbreaks of measles have centered in specific communities, pointing to the influence of social ties on vaccination practices. This study adds to the conversation on public understanding of vaccine-related science, documenting how the individualist epistemologies highlighted in prior research are externalized and validated in communication with others, focusing on how the narrative strategies used to do so contribute to community building among vaccine refusing and hesitant parents. Through qualitative content analysis of testimonials given to the creators of the anti-vaccination documentary VaxXed, we identify how the common narrative strategies used to question the scientific consensus on vaccines-distrust of doctors, self-diagnosis, building credibility, advocacy, and community building-build a competing consensus based on personal expertise. With this approach, we are better able to understand how participation in online communities strengthens the privileging of individualist epistemologies among vaccine refusing and hesitant parents.

Characteristics, Early Development and Outcome of Parent-Reported Regression in Autism Spectrum Disorder

This study explored regression patterns in 100 children with ASD (3-11 years) using several approaches to enhance the validity of retrospective parent report. Both early development and outcome were examined in regression groups defined by 36 months age cut-off and two underlying empirical patterns based on type and onset age. Results over regression groups were generally consistent. During early development, children with regression showed a similar amount of social atypicalities and stereotyped behaviour as compared to children without regression. However, parents indicated less communication skills which could be a valuable predictor of regression. Development after regression was characterised by early language delay and more restricted and repetitive behaviour. The findings provide insight into the diagnosis and prognosis of regression in ASD.

Prevalence and correlates of autism spectrum disorder in Qatar: a national study

BACKGROUND

Few epidemiological data on autism spectrum disorders (ASD) exist for Arabic countries. We conducted the first survey of ASD in Qatar, a population with high consanguinity level.

METHODS

This cross-sectional survey was conducted from 2015 to 2018 in Qatar school-age children (N = 176,960) from national and immigrant families. Children diagnosed with ASD were identified through medical centers and special needs schools. Records were abstracted and supplemented by parental interviews. Additionally, children attending 93 schools were screened; ASD case status was confirmed in random samples of screen-positive and screen-negative children. Prevalence was estimated after taking into account different sampling fractions and participation rates at each survey phase.

RESULTS

One thousand three hundred and ninety-three children already diagnosed with ASD were identified. Among 9,074 school survey participants, 760 screen-negative children and 163 screen-positive children were evaluated; 17 were confirmed to have ASD including five children newly diagnosed. Prevalence was 1.14% (95% CI: 0.89-1.46) among 6- to 11-year-olds. ASD was reported in full siblings/extended relatives in 5.9% (95% CI: 0.042-0.080)/11.8% (95% CI: 0.095-0.146) families. First-degree consanguinity in Qatari cases (45%) was comparable to known population levels. Among 844 ASD cases (mean age: 7.2 years; 81% male), most children experienced language delay (words: 75.1%; phrase speech: 91.4%), and 19.4% reported developmental regression. At the time of the survey, persisting deficits in expressive language (19.4%) and peer interactions (14.0%) were reported in conjunction with behavioral problems (ADHD: 30.2%; anxiety: 11.0%). In multivariate logistic regression, ASD severity was associated with parental consanguinity, gestational diabetes, delay in walking, and developmental regression.

CONCLUSIONS

ASD prevalence in Qatar is consistent with recent international studies. The methods employed in this study should help designing comparable surveys in the region. We estimated that 187,000 youths under age 20 have ASD in Gulf countries. This figure should assist in planning health and educational services for a young, fast-growing population.

Changing conceptualizations of regression: What prospective studies reveal about the onset of autism spectrum disorder

Until the last decade, studies of the timing of early symptom emergence in autism spectrum disorder (ASD) relied upon retrospective methods. Recent investigations, however, are raising significant questions about the accuracy and validity of such data. Questions about when and how behavioral signs of autism emerge may be better answered through prospective studies, in which infants are enrolled near birth and followed longitudinally until the age at which ASD can be confidently diagnosed or ruled out. This review summarizes the results of recent studies that utilized prospective methods to study infants at high risk of developing ASD due to family history. Collectively, prospective studies demonstrate that the onset of ASD involves declines in the rates of key social and communication behaviors during the first years of life for most children. This corpus of literature suggests that regressive onset patterns occur much more frequently than previously recognized and may be the rule rather than the exception.

Regression in autism spectrum disorder: A critical overview of retrospective findings and recommendations for future research

Historically, two onset patterns in autism spectrum disorder (ASD) were described: early onset of symptoms and regression in which one-third appear to show a loss of previously established skills in the second year of life. Since this phenomenon could represent a distinct ASD subtype and provide more insight into the etiology, diagnosis, and prognosis, many studies have compared these two groups. The present review discusses definitions, etiology, and methods used in research with a retrospective design and provides an overview of the results on early development and outcomes. However, retrospective research has not provided clear answers on regression as a distinct subtype of ASD and the historic division between early onset and regression does not seem to fit the empirical findings. Based on inconsistent results, future research on onset patterns in ASD needs to be more systematic on the definitions and methods used. Several recommendations to enhance the reliability of future retrospective results are discussed. The combination of a categorical and dimensional approach provides a new interesting framework.

Gene Disrupting Mutations Associated with Regression in Autism Spectrum Disorder

Approximately one-third of children with autism spectrum disorder (ASD) reportedly lose skills within the first 3 years, yet a causal mechanism remains elusive. Considering evidence of strong genetic effects for ASD and findings that distinct phenotypes in ASD associate with specific genetic events, we examined rates of parent-reported regression in the Simons Simplex Collection with likely gene disrupting mutations from five distinct classes: FMRP target genes, genes encoding chromatin modifiers, genes expressed preferentially in embryos, genes encoding postsynaptic density proteins, and essential genes. Children with ASD and mutations in postsynaptic density genes were more likely to experience regression, while a trend suggested that children with ASD and mutations in embryonic genes were less likely to have skill losses.

Arcuate Fasciculus in Autism Spectrum Disorder Toddlers with Language Regression

Language regression is observed in a subset of toddlers with autism spectrum disorder (ASD) as initial symptom. However, such a phenomenon has not been fully explored, partly due to the lack of definite diagnostic evaluation methods and criteria. Materials and Methods: Fifteen toddlers with ASD exhibiting language regression and fourteen age-matched typically developing (TD) controls underwent diffusion tensor imaging (DTI). DTI parameters including fractional anisotropy (FA), average fiber length (AFL), tract volume (TV) and number of voxels (NV) were analyzed by Neuro 3D in Siemens syngo workstation. Subsequently, the data were analyzed by using IBM SPSS Statistics 22. Results: Compared with TD children, a significant reduction of FA along with an increase in TV and NV was observed in ASD children with language regression. Note that there were no significant differences between ASD and TD children in AFL of the arcuate fasciculus (AF). Conclusions: These DTI changes in the AF suggest that microstructural anomalies of the AF white matter may be associated with language deficits in ASD children exhibiting language regression starting from an early age.

Loss of skills and onset patterns in neurodevelopmental disorders: Understanding the neurobiological mechanisms

Patterns of onset in Autism Spectrum Disorder, including a pattern that includes loss of previously acquired skills, have been identified since the first reports of the disorder. However, attempts to study such "regression" have been limited to clinical studies, that until recently mostly involved retrospective reports. The current report reflects discussion that occurred at an NIMH convened meeting in 2016 with the purpose of bridging clinical autism research with basic and translational work in this area. This summary describes the state of the field with respect to clinical studies, describing gaps in knowledge based on limited methods and prospective data collected. Biological mechanisms that have been shown to account for regression early in development in specific conditions are discussed, as well as potential mechanisms that have not yet been explored. Suggestions include use of model systems during the developmental period and cutting-edge methods, including non-invasive imaging that may afford opportunities for a better understanding of the neurobiological pathways that result in loss of previously-attained skills. Autism Res 2018, 11: 212-222. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

LAY SUMMARY

Loss of previously acquired skills, or regression, has been reported in Autism Spectrum Disorder since Kanner's reports in the 1950's. The current report reflects discussion from an NIMH convened meeting in 2016 with the purpose of bridging clinical autism research with basic and translational work in this area. This summary describes the state of the field regarding clinical studies and suggests use of model systems during the developmental period and cutting-edge methods, for a better understanding of the neurobiological pathways that result in loss of previously-attained skills.

Parent-Reported Developmental Regression in Autism: Epilepsy, IQ, Schizophrenia Spectrum Symptoms, and Special Education

Examined the psychiatric and clinical correlates of loss of previously acquired skills (regression) as reported by parents of youth with autism spectrum disorder (ASD). Study sample comprised 6- to 18-year old (N = 213) children and adolescents with ASD. Parents reported regression in 77 (36%) youth. A more homogeneous subgroup with regression between 18 and 36 months (n = 48) had higher rates of intellectual disability, epilepsy, and special education, more socially restrictive educational settings, and more severe ASD communication deficits and schizophrenia spectrum symptoms than non-regressed youth (n = 136). Similar results were obtained for a more inclusive definition of regression (n = 77). A brief parent report of developmental regression may be a useful clinical indicator of later general functioning.

Mitochondrial dysfunction in the gastrointestinal mucosa of children with autism: A blinded case-control study

Gastrointestinal (GI) symptoms are prevalent in autism spectrum disorder (ASD) but the pathophysiology is poorly understood. Imbalances in the enteric microbiome have been associated with ASD and can cause GI dysfunction potentially through disruption of mitochondrial function as microbiome metabolites modulate mitochondrial function and mitochondrial dysfunction is highly associated with GI symptoms. In this study, we compared mitochondrial function in rectal and cecum biopsies under the assumption that certain microbiome metabolites, such as butyrate and propionic acid, are more abundant in the cecum as compared to the rectum. Rectal and cecum mucosal biopsies were collected during elective diagnostic colonoscopy. Using a single-blind case-control design, complex I and IV and citrate synthase activities and complex I-V protein quantity from 10 children with ASD, 10 children with Crohn’s disease and 10 neurotypical children with nonspecific GI complaints were measured. The protein for all complexes, except complex II, in the cecum as compared to the rectum was significantly higher in ASD samples as compared to other groups. For both rectal and cecum biopsies, ASD samples demonstrated higher complex I activity, but not complex IV or citrate synthase activity, compared to other groups. Mitochondrial function in the gut mucosa from children with ASD was found to be significantly different than other groups who manifested similar GI symptomatology suggesting a unique pathophysiology for GI symptoms in children with ASD. Abnormalities localized to the cecum suggest a role for imbalances in the microbiome, potentially in the production of butyrate, in children with ASD.

Reliability of parent recall of symptom onset and timing in autism spectrum disorder

Past events are often reported as occurring more recently than they actually took place, an error called forward telescoping. This study examined whether forward telescoping was evident in parent reports of autism spectrum disorder symptom emergence and onset classification. Parents were interviewed when their child was 2-3 years old (Time 1) and approximately 6 years old (Time 2). Significant forward telescoping was found in both age of social regression and age when language milestones were achieved, but not age of language regression. The correspondence between Time 1 and Time 2 onset report was low ( kappa = 0.38). Approximately one-quarter of the sample changed onset categories, most often due to parents not recalling a regression at Time 2 that they had reported at Time 1. These results challenge the use of retrospective methods in determining onset patterns.

The Early Origins of Autism

Autism spectrum disorders (ASDs) are neurodevelopmental disorders whose core features of impaired social communication and atypical repetitive behaviors and/or restrictions in range of interests emerge in toddlerhood and carry significant implications at successive stages of development. The ability to reliably identify most cases of the condition far earlier than the average age of diagnosis presents a novel opportunity for early intervention, but the availability of such an intervention is disparate across US communities, and its impact is imperfectly understood. New research may transform the clinical approach to these conditions in early childhood.

Emergence of autism spectrum disorder in children from simplex families: relations to parental perceptions of etiology

Current research describes a four-category scheme of Autism Spectrum Disorder (ASD) onset: early, regressive, plateau, delay + regression. To replicate prevalence of different onset types, ASD onset (per the Autism Diagnostic Interview--Revised) was examined in a large North American sample; for a subset, parents' causal beliefs were ascertained via the Revised Illness Perception Questionnaire to examine potential associations with ASD-onset types. Onset rates were similar across samples, with a slightly higher proportion of children in the subsample categorized with regression. Top-rated causes of ASD were genetics, brain structure, will of God, toxins in vaccines, and environmental pollution. Parents reporting regression more often believed that toxins in vaccines caused ASD. Influences on treatment selection and broader public-health ramifications are discussed.

Brief report: regression timing and associated features in MECP2 duplication syndrome

The aim of this study was to determine the frequency, timing, and associated features of developmental regression in MECP2 duplication syndrome. We also examined whether duplication size was associated with regression. Comprehensive psychological evaluations were used to assess 17 boys with MECP2 duplication syndrome. Information about regression was gathered via parent report. Eight of 17 boys exhibited regression in language skills, while seven of 17 exhibited regression in other skill areas. Regression in "other skill" areas coincided with seizure onset and with a prior autism diagnosis in six of seven participants. Regression was not associated with duplication size. Questions remain as to why some boys regress, and future work is necessary to understand the underlying mechanism(s) that causes regression.

Parent-reported gastro-intestinal symptoms in children with autism spectrum disorders

The objective of this study is to investigate whether parentally-reported gastro-intestinal (GI) symptoms are increased in a population-derived sample of children with autism spectrum disorders (ASD) compared to controls. Participants included 132 children with ASD and 81 with special educational needs (SEN) but no ASD, aged 10-14 years plus 82 typically developing (TD) children. Data were collected on GI symptoms, diet, cognitive abilities, and developmental histories. Nearly half (weighted rate 46.5 %) of children with ASD had at least one individual lifetime GI symptom compared with 21.8 % of TD children and 29.2 % of those with SEN. Children with ASD had more past and current GI symptoms than TD or SEN groups although fewer current symptoms were reported in all groups compared with the past. The ASD group had significantly increased past vomiting and diarrhoea compared with the TD group and more abdominal pain than the SEN group. The ASD group had more current constipation (when defined as bowel movement less than three times per week) and soiling than either the TD or SEN groups. No association was found between GI symptoms and intellectual ability, ASD severity, ASD regression or limited or faddy diet. Parents report more GI symptoms in children with ASD than children with either SEN or TD children but the frequency of reported symptoms is greater in the past than currently in all groups.

Cognitive and language skills in adults with autism: a 40-year follow-up

BACKGROUND

It is well established that very few individuals with autism spectrum disorders (ASD) and an IQ below 70 are able to live independently as adults. However, even amongst children with an IQ in the normal range, outcome is very variable. Childhood factors that predict later stability, improvement or decline in cognitive functioning remain uncertain and, in particular, very little is known about trajectories in later adulthood.

METHOD

Changes in cognitive and language ability from childhood to adulthood were assessed in 60 individuals with autism, all of whom had an IQ in the average range as children. Mean age in childhood = 6 years (range 2-13 years); mean age in adulthood = 44 years (range 29-64 years). Trajectories of change and factors related to current cognitive abilities were explored.

RESULTS

For the majority of participants (N = 45, 75%), who were testable both as children and adults, IQ remained very stable and language also improved over time. However, 15 individuals could not be assessed on standard tests as adults and their developmental level could be estimated only on the Vineland Adaptive Behavior Scales. Almost all these adults (apart from one who had suffered a major stroke) showed severe aggressive or self-injurious behaviours; none had ever developed language above a 3-year level, and seven had developed epilepsy.

CONCLUSIONS

For most individuals with autism who had an IQ in the average range (i.e. ≥ 70) as children, childhood IQ proved a reliable predictor of cognitive functioning well into mid- to- later adulthood. However, a significant minority was no longer testable on standard tests as adults. Their current very low levels of functional ability were generally associated with severe behavioural disturbance and persisting and severe language impairment; 50% of these individuals had also developed epilepsy, pointing to the role of organic brain dysfunction. Implications for early intervention are discussed.

Early intersubjective skills and the understanding of intentionality in young children with Down syndrome

This study examined the relationship between early intersubjective skills (joint attention and affect sharing) and the development of the understanding of intentionality in 16 young children with Down syndrome (DS) and 16 developmentally matched children with other developmental disabilities (DD). The study of intentionality focuses on how children come to understand the goal-directed actions of others and is an important precursor to the development of more complex social cognitive skills, such as theory of mind. Joint attention and affect sharing were examined using the Early Social Communication Scales (Mundy, Sigman, & Kasari, 1990; Seibert, Hogan, & Mundy, 1982). Meltzoff's (1995) behavioral reenactment paradigm was used to examine the understanding of intentionality. For children with DS, higher rates of affect sharing were associated with poorer intention reading abilities. This pattern was not observed in children with other DD. These results suggest that the intersubjective strengths associated with DS may not support the development of intentionality-interpretation skills. Future research is needed to explore if children with DS have the joint attention behaviors needed to be intentional.

Prevalence and onset of regression within autism spectrum disorders: a meta-analytic review

Rates and onset of regression were meta-analyzed from 85 articles representing 29,035 participants with autism spectrum disorders (ASD). Overall prevalence rate for regression was 32.1, 95 % CI [29.5, 34.8] occurring at mean of 1.78 years, 95 % CI [1.67, 1.89]. Regression prevalence rates differed according to four types of regression: language regression, 24.9 %; language/social regression, 38.1 %; mixed regression, 32.5 %; and unspecified regression, 39.1 %. Regression prevalence also differed according to sampling method: population-based prevalence was 21.8 %, clinic-based prevalence was 33.6 %, and parent survey-based prevalence was 40.8 %. Risk of regression was equal for males and females, but higher for individuals diagnosed with autism versus another ASD. Later age of regression onset was predicted by older age of child.

DSM-5 and autism spectrum disorders (ASDs): an opportunity for identifying ASD subtypes

The heterogeneous clinical presentations of individuals with autism spectrum disorders (ASDs) poses a significant challenge for sample characterization and limits the interpretability and replicability of research studies. The Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) diagnostic criteria for ASD, with its dimensional approach, may be a useful framework to increase the homogeneity of research samples. In this review, we summarize the revisions to the diagnostic criteria for ASD, briefly highlight the literature supporting these changes, and illustrate how DSM-5 can improve sample characterization and provide opportunities for researchers to identify possible subtypes within ASD.

Trajectories of autism severity in children using standardized ADOS scores

OBJECTIVES

To plot longitudinal trajectories of autism spectrum disorder (ASD) severity from early childhood to early adolescence. In line with reported trajectories in toddlers, we hypothesize that a substantial minority of children will show marked changes in ASD severity over time, with "Improvers" demonstrating the highest mean baseline and rate of growth in verbal IQ (VIQ).

METHODS

Patients included 345 clinic referrals and research participants with best-estimate clinical diagnoses of ASD at 1 or more time points, and repeated Autism Diagnostic Observation Schedule (ADOS), VIQ, and nonverbal IQ scores. Standardized ADOS severity scores were applied to 1026 assessments collected longitudinally between the ages of 2 and 15 (VIQ at most recent assessment: mean = 58, SD = 35). Scores were fitted for latent severity trajectory classes with and without covariates. Adaptive behavior and VIQ trajectories over time were modeled within each of the best-fit latent classes.

RESULTS

A 4-class model best represented the observed data. Over 80% of participants were assigned to persistent (stable) high or moderately severe classes; 2 small classes respectively increased or decreased in severity over time. Age, gender, race, and nonverbal IQ did not predict class membership; VIQ was a significant predictor. Baseline VIQ was highest in the improving and worsening classes; it increased at the greatest rate in the improving class. Adaptive behavior declined in all but the improving class, with consistent impairment in all classes.

CONCLUSIONS

If replicated, identified trajectory classes of ADOS severity may contribute to clinical prognosis and to subtyping samples for neurobiological and genetic research.

Brief report: Association between behavioral features and gastrointestinal problems among children with autism spectrum disorder

Recent reports suggest certain behaviors among children with autism spectrum disorders (ASD) may indicate underlying gastro-intestinal (GI) problems, and that the presence of these behaviors may help alert primary care providers to the need to evaluate a child with ASD for GI problems. The purpose of this population-based study of 487 children with ASD, including 35 (7.2%) with a medically documented history of GI problems, was to compare behavioral features of children with and without a history of GI problems. Unusual sleeping or eating habits and oppositional behavior were significantly associated with GI problems. These behaviors, however, were frequent in both children with and without GI problems, suggesting they may have limited utility in a screening capacity for GI problems.

Regression in children with autism spectrum disorders

OBJECTIVES

To understand the characteristics of autistic regression and to compare the clinical and developmental profile of children with autism spectrum disorders (ASD) in whom parents report developmental regression with age matched ASD children in whom no regression is reported.

METHODS

Participants were 35 (Mean age = 3.57 y, SD = 1.09) children with ASD in whom parents reported developmental regression before age 3 y and a group of age and IQ matched 35 ASD children in whom parents did not report regression. All children were recruited from the outpatient Child Psychology Clinic of the Department of Pediatrics of a tertiary care teaching hospital in North India. Multi-disciplinary evaluations including neurological, diagnostic, cognitive, and behavioral assessments were done. Parents were asked in detail about the age at onset of regression, type of regression, milestones lost, and event, if any, related to the regression. In addition, the Childhood Autism Rating Scale (CARS) was administered to assess symptom severity.

RESULTS

The mean age at regression was 22.43 mo (SD = 6.57) and large majority (66.7%) of the parents reported regression between 12 and 24 mo. Most (75%) of the parents of the regression-autistic group reported regression in the language domain, particularly in the expressive language sector, usually between 18 and 24 mo of age. Regression of language was not an isolated phenomenon and regression in other domains was also reported including social skills (75%), cognition (31.25%). In majority of the cases (75%) the regression reported was slow and subtle. There were no significant differences in the motor, social, self help, and communication functioning between the two groups as measured by the DP II.There were also no significant differences between the two groups on the total CARS score and total number of DSM IV symptoms endorsed. However, the regressed children had significantly (t = 2.36, P = .021) more social deficits as per the DSM IV as compared to the non-regressed children with autism.

CONCLUSIONS

Autism with regression is not characterized by a distinctive developmental or symptom profile. Developmental regression may, however, be an early and reliable marker in a significant number of children with autism.

Risk factors for autistic regression: results of an ambispective cohort study

A subgroup of children diagnosed with autism experience developmental regression featured by a loss of previously acquired abilities. The pathogeny of autistic regression is unknown, although many risk factors likely exist. To better characterize autistic regression and investigate the association between autistic regression and potential influencing factors in Chinese autistic children, we conducted an ambispective study with a cohort of 170 autistic subjects. Analyses by multiple logistic regression showed significant correlations between autistic regression and febrile seizures (OR = 3.53, 95% CI = 1.17-10.65, P = .025), as well as with a family history of neuropsychiatric disorders (OR = 3.62, 95% CI = 1.35-9.71, P = .011). This study suggests that febrile seizures and family history of neuropsychiatric disorders are correlated with autistic regression.

Brief report: symptom onset patterns and functional outcomes in young children with autism spectrum disorders

This study examined the relationship between onset status and current functioning using a recently proposed onset classification system in 272 young children with autism spectrum disorder (ASD). Participants were classified into one of the following groups, based on parent report using the Autism Diagnostic Interview--Revised: Early Onset (symptoms by 12 months, no loss), Delay + Regression (symptoms by 12 months plus loss), Plateau (no early symptoms or loss), and Regression (no early symptoms, followed by loss). Findings indicate that current functioning does not differ according to onset pattern, calling into question the use of onset categorizations for prognostic purposes in children with ASD.

Perinatal stress, brain inflammation and risk of autism-review and proposal

BACKGROUND

Autism Spectrum Disorders (ASD) are neurodevelopmental disorders characterized by varying deficits in social interactions, communication, and learning, as well as stereotypic behaviors. Despite the significant increase in ASD, there are few if any clues for its pathogenesis, hampering early detection or treatment. Premature babies are also more vulnerable to infections and inflammation leading to neurodevelopmental problems and higher risk of developing ASD. Many autism "susceptibility" genes have been identified, but "environmental" factors appear to play a significant role. Increasing evidence suggests that there are different ASD endophenotypes.

DISCUSSION

We review relevant literature suggesting in utero inflammation can lead to preterm labor, while insufficient development of the gut-blood-brain barriers could permit exposure to potential neurotoxins. This risk apparently may increase in parents with "allergic" or autoimmune problems during gestation, or if they had been exposed to stressors. The presence of circulating auto-antibodies against fetal brain proteins in mothers is associated with higher risk of autism and suggests disruption of the blood-brain-barrier (BBB). A number of papers have reported increased brain expression or cerebrospinal fluid (CSF) levels of pro-inflammatory cytokines, especially TNF, which is preformed in mast cells. Recent evidence also indicates increased serum levels of the pro-inflammatory mast cell trigger neurotensin (NT), and of extracellular mitochondrial DNA (mtDNA), which is immunogenic. Gene mutations of phosphatase and tensin homolog (PTEN), the negative regulator of the mammalian target of rapamycin (mTOR), have been linked to higher risk of autism, but also to increased proliferation and function of mast cells.

SUMMARY

Premature birth and susceptibility genes may make infants more vulnerable to allergic, environmental, infectious, or stress-related triggers that could stimulate mast cell release of pro-inflammatory and neurotoxic molecules, thus contributing to brain inflammation and ASD pathogenesis, at least in an endophenotype of ASD patients.

The combined measles, mumps, and rubella vaccines and the total number of vaccines are not associated with development of autism spectrum disorder: the first case-control study in Asia

OBJECTIVE

The aim of this study was to investigate the relationship between autism spectrum disorder (ASD) and general vaccinations, including measles-mumps-rubella (MMR) vaccine, in Japanese subjects, a population with high genetic homogeneity.

PATIENTS AND METHODS

A case-control study was performed. Cases (n=189) were diagnosed with ASD, while controls (n=224) were volunteers from general schools, matched by sex and birth year to cases. Vaccination history and prenatal, perinatal, and neonatal factors from the Maternal and Child Health handbook, which was part of each subject's file, were examined. To determine the relationship between potential risk factors and ASD, crude odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated, and the differences in mean values of the quantitative variables between cases and controls were analyzed using an unpaired t-test. Moreover, MMR vaccination and the effect of the number of vaccine injections were investigated using a conditional multiple regression model.

RESULTS

For MMR vaccination, the OR was 1.04 (95% CI, 0.65-1.68), and no significant differences were found for the other vaccines. For all of the prenatal, perinatal and neonatal factors, there were no significant differences between cases and controls. Furthermore, regarding the presence of ASD, MMR vaccination and the number of vaccine injections had ORs of 1.10 (95% CI, 0.64-1.90) and 1.10 (95% CI, 0.95-1.26), respectively, in the conditional multiple regression model; no significant differences were found.

CONCLUSIONS

In this study, there were not any convincing evidences that MMR vaccination and increasing the number of vaccine injections were associated with an increased risk of ASD in a genetically homogeneous population. Therefore, these findings indicate that there is no basis for avoiding vaccination out of concern for ASD.

Long term antibiotic therapy may be an effective treatment for children co-morbid with Lyme disease and autism spectrum disorder

Patients diagnosed with Lyme disease share many of the same physical manifestations as those diagnosed with an Autism Spectrum Disorder (ASD). In this study four male children (ages 26-55 months) who have an ASD diagnosis and one male child (age -O meets state and federal requirements for providing a comprehensive, ongoing assessment of a child with an ASD [33]. The SAP-O form measures children's abilities using observational, authentic assessment procedures in the domains of joint attention, symbol use, mutual regulation, and self regulation via observations of specific behaviors in familiar settings [33]. The five children tested positive for Lyme disease and their SAP-O score was evaluated before and after 6 months of antibiotic therapy. Each child was prescribed 200mg of amoxicillin three times per day and three of the five children were prescribed an additional 50mg of Azithromycin once per day. All of the children's scores on the SAP-O assessment improved after 6 months of antibiotic therapy. The assessors also reported anecdotal data of improved speech, eye contact, sleep behaviors, and a reduction of repetitive behaviors.

The phenomenology of autistic regression: subtypes and associated factors

This study aimed to investigate the association of autistic regression (AR) and subtypes of AR with medical, developmental and psychiatric factors. Fifty-seven children with autistic spectrum disorders (ASD) were included in the study. Two types of AR are defined as regression after a normal social/language development (type 1) and regression as the worsening of previously reported autistic features (type 2). The frequency of history of AR was 56.1%. Male gender and sleep problems were found to be associated with a positive history of AR. The frequency of gastrointestinal complaints/diseases was higher in children with regression type 2 when compared to the children with regression type 1. Future studies with larger sample size and prospective design will contribute to clarifying the phenomenology and the associated factors of AR.

Does theory of mind performance differ in children with early-onset and regressive autism?

A deficit in theory of mind (ToM), or the ability to infer the mental states of others, has been implicated as one of the major characteristics of Autism Spectrum Disorder (ASD); however, little attention has been devoted to possible differences in ToM ability within ASD. The current study examined ToM performance in children with early-onset autism and regressive autism in comparison to typically developing children. Results indicated that children in the regressive autism group performed significantly better than the early-onset autism group on the non-verbal appearance-reality task. Additionally, Fisher's exact tests indicated a pattern of lowest scores in the early-onset group and highest scores in the typically developing group, whereas the regressive autism group tended to score in between the early-onset and typically developing groups. The apparent heterogeneity in ToM performance within ASD could account for the lack of universality in ToM ability found in previous studies.

Impaired carbohydrate digestion and transport and mucosal dysbiosis in the intestines of children with autism and gastrointestinal disturbances

Gastrointestinal disturbances are commonly reported in children with autism, complicate clinical management, and may contribute to behavioral impairment. Reports of deficiencies in disaccharidase enzymatic activity and of beneficial responses to probiotic and dietary therapies led us to survey gene expression and the mucoepithelial microbiota in intestinal biopsies from children with autism and gastrointestinal disease and children with gastrointestinal disease alone. Ileal transcripts encoding disaccharidases and hexose transporters were deficient in children with autism, indicating impairment of the primary pathway for carbohydrate digestion and transport in enterocytes. Deficient expression of these enzymes and transporters was associated with expression of the intestinal transcription factor, CDX2. Metagenomic analysis of intestinal bacteria revealed compositional dysbiosis manifest as decreases in Bacteroidetes, increases in the ratio of Firmicutes to Bacteroidetes, and increases in Betaproteobacteria. Expression levels of disaccharidases and transporters were associated with the abundance of affected bacterial phylotypes. These results indicate a relationship between human intestinal gene expression and bacterial community structure and may provide insights into the pathophysiology of gastrointestinal disturbances in children with autism.

Onset patterns in autism: correspondence between home video and parent report

OBJECTIVE

The onset of autism is usually conceptualized as occurring in one of two patterns, early onset or regressive. This study examined the number and shape of trajectories of symptom onset evident in coded home movies of children with autism and examined their correspondence with parent report of onset.

METHOD

Four social-communicative behaviors were coded from the home video of children with autism (n = 52) or typical development (n = 23). All home videos from 6 through 24 months of age were coded (3199 segments). Latent class modeling was used to characterize trajectories and determine the optimal number needed to describe the coded home video. These trajectories were then compared with parent reports of onset patterns, as defined by the Autism Diagnostic Interview-Revised.

RESULTS

A three-trajectory model best fit the data from the participants with autism. One trajectory displayed low levels of social-communication across time. A second trajectory displayed high levels of social-communication early in life, followed by a significant decrease over time. A third trajectory displayed initial levels of behavior that were similar to the typically developing group but little progress in social-communication with age. There was poor correspondence between home video-based trajectories and parent report of onset.

CONCLUSIONS

More than two onset categories may be needed to describe the ways in which symptoms emerge in children with autism. There is low agreement between parent report and home video, suggesting that methods for improving parent report of early development must be developed.

Developmental surveillance of infants and toddlers by maternal and child health nurses in an Australian community-based setting: promoting the early identification of autism spectrum disorders

Although signs of autism spectrum disorders (ASDs) are evident during the first year of life, few children are diagnosed prior to 3 years. The objective in this article is to highlight the role that primary health care professionals can play in the early identification of ASDs by briefly outlining the successful implementation of The Social Attention and Communication Study. Maternal and child health nurses were trained on the early signs of ASDs, which enabled them to identify these children prior to 2 years. The training procedure used will be outlined, and the early signs that were monitored will be explained in detail. It is recommended that routine monitoring for ASDs in infancy and toddlerhood become standard practice among all primary health care professionals.

Early developmental regression in autism spectrum disorder: evidence from an international multiplex sample

The characteristics of early developmental regression (EDR) were investigated in individuals with ASD from affected relative pairs recruited to the International Molecular Genetic Study of Autism Consortium (IMGSAC). Four hundred and fifty-eight individuals with ASD were recruited from 226 IMGSAC families. Regression before age 36 months occurred in 23.9% of individuals. The observed concordance rate for EDR within sibling pairs (18.9%) was not significantly above the rate expected under independence (13.5%, p = 0.10). The rate of regression in individuals with ASD from multiplex families was similar to that reported in singleton and epidemiological samples. Regression concordance data were not supportive of a separate familial influence on EDR, other than as a part of autism itself.

Sleep in children with autism with and without autistic regression

The purpose of the present investigation was to characterize and compare traditional sleep architecture and non-rapid eye movement (NREM) sleep microstructure in a well-defined cohort of children with regressive and non-regressive autism, and in typically developing children (TD). We hypothesized that children with regressive autism would demonstrate a greater degree of sleep disruption either at a macrostructural or microstructural level and a more problematic sleep as reported by parents. Twenty-two children with non-regressive autism, 18 with regressive autism without comorbid pathologies and 12 with TD, aged 5-10years, underwent standard overnight multi-channel polysomnographic evaluation. Parents completed a structured questionnaire (Childrens' Sleep Habits Questionnaire-CSHQ). The initial hypothesis, that regressed children have more disrupted sleep, was supported by our findings that they scored significantly higher on CSHQ, particularly on bedtime resistance, sleep onset delay, sleep duration and night wakings CSHQ subdomains than non-regressed peers, and both scored more than typically developing controls. Regressive subjects had significantly less efficient sleep, less total sleep time, prolonged sleep latency, prolonged REM latency and more time awake after sleep onset than non-regressive children and the TD group. Regressive children showed lower cyclic alternating pattern (CAP) rates and A1 index in light sleep than non-regressive and TD children. Our findings suggest that, even though no particular differences in sleep architecture were found between the two groups of children with autism, those who experienced regression showed more sleep disorders and a disruption of sleep either from a macro- or from a microstructural viewpoint.

Imitating actions on objects in early-onset and regressive autism: effects and implications of task characteristics on performance

This study was designed to examine the nature of object imitation performance in early autism. We hypothesized that imitation would be relatively preserved when behaviors on objects resulted in salient instrumental effects. We designed tasks in which, in one condition, the motor action resulted in a salient, meaningful effect on an object, whereas in the other condition, the same action resulted in a less salient effect because of differing object characteristics. The motor aspects of the tasks did not vary across conditions. Four participant groups of 2- to 5-year-olds were examined: 17 children with early-onset autism, 24 children with regressive onset autism, 22 children with developmental delays, and 22 children with typical development. Groups were matched on nonverbal skills, and differences in verbal development were examined as a moderator of imitative ability. Results revealed an interaction of group by condition, with the combined autism group failing more tasks than the combined comparison groups, and failing more tasks in the less salient condition than in the more salient condition, as hypothesized. Analyses of autism subgroups revealed these effects were primarily because of the regression onset group. Accuracy of motor performance was examined by analyzing errors. Among children passing imitative acts, there were no group differences and no condition effects in the number, type, or pattern of performance errors. Among children passing the tasks, the group with autism did not demonstrate more emulation errors (imitating the goal but not the means) than other groups. There was no evidence that either motor or attentional aspects of the tasks contributed to the poorer imitative performance of the children with autism.

The prodrome of autism: early behavioral and biological signs, regression, peri- and post-natal development and genetics

Autism is one of the most heritable neurodevelopmental conditions and has an early onset, with symptoms being required to be present in the first 3 years of life in order to meet criteria for the 'core' disorder in the classification systems. As such, the focus on identifying a prodrome over the past 20 years has been on pre-clinical signs or indicators that will be present very early in life, certainly in infancy. A number of novel lines of investigation have been used to this end, including retrospective coding of home videos, prospective population screening and 'high risk' sibling studies; as well as the investigation of pre- and peri-natal, brain developmental and other biological factors. While no single prodromal sign is expected to be present in all cases, a picture is emerging of indicative prodromal signs in infancy and initial studies are being undertaken to attempt to ameliorate early presentation and even 'prevent' emergence of the full syndrome.

Children with autism spectrum disorders: a comparison of those who regress vs. those who do not

OBJECTIVE

While autism spectrum disorders (ASD) constitute a group of similar conditions, considerable heterogeneity in symptoms of these neurodevelopmental disorders have been noted. One of the most important, yet least studied, of these factors is developmental regression.

METHODS

One-hundred and twenty-five children were studied and broken down into the following three groups: ASD children with and without substantial regression and typically developing children. In study one, the three groups were compared on global measures of ASD symptomatology, comorbid psychopathology, challenging behaviour and social skills. In study two, the two ASD groups were compared on each individual item from the dependent measures.

RESULTS

Mean age when regression occurred was 27.76 months. The ASD children as a whole differed from the typically developing controls, showing more symptoms of ASD, as would be expected, and poorer social skills, while differences were also noted between the two ASD groups.

CONCLUSIONS

It was determined that children with ASD who regress present with a distinct behavioural profile when compared to children with ASD who do not regress, which included greater levels of impairment on global measures of ASD symptomatology, comorbid psychopathology, challenging behaviour and social skills.

Autism spectrum disorders in infancy and toddlerhood: a review of the evidence on early signs, early identification tools, and early diagnosis

To date, the biological basis of autism spectrum disorders (ASDs) remains unknown. Thus, identification and diagnosis are reliant on behavioral presentation and developmental history. There have been significant advances in our knowledge of the early signs of ASD through the use of retrospective videotape analysis, parental report, screening studies, and more recently, studies on high-risk infant siblings. Despite behavioral markers being identified within the first year of life, the current average age of diagnosis for ASD remains at approximately 3 years or older. Consequently, these children are not receiving intervention in their early years, which is increasingly recognized as an important time to begin intervention. There remains little research on the prospective identification of these children in a community-based sample before 18 months. It is recommended that future prospective studies monitor behavior repeatedly over time, thereby increasing the opportunity to identify early manifestations of ASD and facilitating the charting of subtle behavioral changes that occur in the development of infants and toddlers with ASD.

Developmental regression in children with an autism spectrum disorder identified by a population-based surveillance system

This study evaluated the phenomenon of autistic regression using population-based data. The sample comprised 285 children who met the autism spectrum disorder (ASD) case definition within an ongoing surveillance program. Results indicated that children with a previously documented ASD diagnosis had higher rates of autistic regression than children who met the ASD surveillance definition but did not have a clearly documented ASD diagnosis in their records (17-26 percent of surveillance cases). Most children regressed around 24 months of age and boys were more likely to have documented regression than girls. Half of the children with regression had developmental concerns noted prior to the loss of skills. Moreover, children with autistic regression were more likely to show certain associated features, including cognitive impairment.These data indicate that some children with ASD experience a loss of skills in the first few years of life and may have a unique symptom profile.

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.