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

The Influence of Social and Developmental Factors on the Timing of Autism Spectrum Disorder Diagnosis of Preschool-Aged Children: Evidence from a Specialized Chilean Center

We investigated the influence of developmental and social factors on the age of autism diagnosis (AoD) in a cohort of toddlers living in Chile. A cross-sectional study was conducted among 509 preschool children diagnosed with autism spectrum disorder [M = 40.2 months (SD = 8.6), girls: 32%] in the neurodevelopmental unit of a university clinic in Santiago, Chile (2015-2023). Structural changes in the annual trend of AoD were tested. Generalized linear models (gamma distribution) with and without interaction terms were used for the multivariate analysis, adjusting for gender, residential area, year of diagnosis, developmental variables (language regression, delayed walking, and use of expressive verbal language), and primary caregiver age and education level (CEL). 95% confidence intervals of the unstandardized regression coefficients (B) were calculated using 1000 bootstrap resampling to estimate associations. AoD increased between 2021-2022 and decreased in 2023. Female gender (B = 2.72 [1.21-4.23]), no history of language regression (B = 3.97 [1.66-6.28]), and the presence of expressive verbal language at diagnosis (B = 1.57 [0.05-3.08]) were associated with higher AoD. Children whose caregivers had tertiary education were diagnosed earlier than those with ≤ 12 years of formal education. Although the influence of CEL increased with caregiver age, differences between CEL groups were significant only for caregivers aged ≥ 30 years. Improved education and early screening for clinical features of autism among healthcare professionals and the community, with a focus on young children without highly apparent developmental concerns and those from vulnerable social groups, are warranted.

Autism Spectrum Disorder and Sleep

Children and adolescents with autism spectrum disorder (ASD) experience sleep disturbances, particularly insomnia, at rates much higher than the general population. Daytime behavioral problems and parental stress are associated with the resultant sleep deprivation. Behavioral interventions, parental education, and melatonin are effective treatments. The epidemiology of sleep disturbances in youth with ASD is reviewed in this article as well as the latest in treatments.

Risk factors and clinical characteristics of autism spectrum disorder with regression in China

Autism spectrum disorder with regression (ASD-R) is characterized by the loss of previously acquired skills during the initial year of life. This study aimed to investigate the clinical characteristics, patterns of regression, and potential risk factors associated with ASD-R in the Chinese Han population. A case-control study was conducted between September 2020 and March 2022. A total of 186 children were enrolled, including 58 children with ASD-R, 70 with ASD without regression (ASD-NR), and 58 typically developing children. Demographic information, clinical characteristics, and potential risk factors related to ASD-R were assessed using a combination of questionnaires, interviews, and physician assessments. The results revealed that children with ASD-R exhibited more severe impairments in social communication and stereotyped behaviors compared with those with ASD-NR. Language regression, constituting 40% of cases within the ASD-R group, was found to be the most common type of regression. Furthermore, our analysis revealed that fever (OR = 4.01, 95% CI: 1.26-12.76) and diarrhea (OR = 6.32, 95% CI: 1.38-29.03) were identified as significant risk factors for ASD-R. These findings contribute to our understanding of the heterogeneity of ASD and highlight the importance of considering immune responses and gastrointestinal factors in the etiology of ASD-R.

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.

Novel GRIA2 variant in a patient with atypical autism spectrum disorder and psychiatric symptoms: a case report

Background

As sequencing technology has advanced in recent years, a series of synapse-related gene variants have been reported to be associated with autism spectrum disorders (ASDs). The α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor is a subtype of the ionotropic glutamate receptor, whose number or composition changes can regulate the strength and plasticity of synapses.

Case presentation

Here, we report a de novo GRIA2 variant (NM_001083619.3: c.2308G > A, p.Ala770Thr) in a patient with obvious behavior regression and psychiatric symptoms. It encodes GluA2, which is the crucial subunit of the AMPA receptor, and the missense variation is predicted to result in instability of the protein structure.

Conclusions

The association between GRIA2 variants and onset of ASD symptoms is rare, and our study expands the spectrum of phenotypic variations. For patients with an unexplained etiology of ASD accompanied by psychiatric symptoms, genetic causes should be considered, and a complete genetic evaluation should be performed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03702-7.

An Overview of Pediatric Approaches to Child with Developmental Delay Especially if There is Suspicion of ASD in First Few Years of Life

To be a pediatrician means that one encounters many serious childhood health problems and one finds many ways to help families cope with these problems. Symptoms in children can be discrete, and the responsibility of the pediatrician to distinguish normal development from pathological. We are facing a new era in the developmental assessment of children. A cluster of neurodevelopmental disorders includes ASD (autism spectrum disorder) and ADHD (attention deficit hyperactivity disorder). Parents often do not recognize the problem on time. Generally, their first concern is speech delay, leading to the suspicion of hearing problems. Therefore, it is very important to obtain objective anamnestic information and for the child to undergo a careful physical examination, a neurophysiological assessment, and metabolic and genetic testing. The etiology usually is multifactorial: genetic, epigenetic, and non-genetic factors act in combination through various paths. Most children seem to have typical neurodevelopment during first their year. It was found that approximately one-third of children with ASD lose some skills during the preschool period, usually speech related, but sometimes also non-verbal communication, social or play skills. In conclusion we must say that it is very important to recognize the early signs of ASD and any kind of other developmental delay and to start with early intervention. Clinical pediatricians tend to correlate clinical manifestations and biological underpinnings related to neurodevelopmental disorder, especially ASD. Therefore, better treatment possibilities are needed.

Description of Clinician-Diagnosed Regression at Time of Autism Spectrum Disorder Diagnosis in Toddlers

OBJECTIVE

Previous studies have reported varying rates of regression in children with autism spectrum disorder (ASD). We sought to (1) determine the rate of clinician-diagnosed regression for young children with ASD and (2) compare developmental functioning and ASD symptoms of children with versus without regression.

METHODS

We conducted a retrospective chart review of toddlers (age 18-36 months) with Diagnostic and Statistical Manual-5 ASD. We abstracted cognitive, language, adaptive, and motor functioning standard scores and ASD core symptoms. Regression was defined as "clinician-diagnosed regression accompanied by recommendation for a medical workup." We used propensity scores to match each participant with regression (n = 20) one-to-one with a participant without regression (n = 20). We compared the groups on developmental scores using independent sample t tests and on core ASD symptoms using Pearson's χ 2 test.

RESULTS

Of the 500 children with ASD, n = 20 (4%) had regression (defined above). Children with regression had lower Bayley cognitive and language scores and lower Vineland adaptive scores compared with those without regression (cognitive: 78.0 vs 85.5, p < 0.05; language: 56.9 vs 68.2, p < 0.01; adaptive: 70.0 vs 80.3; p < 0.01). There was no difference in motor scores across groups. There were no significant differences in the frequency of exhibiting core ASD symptoms for those with versus without regression.

CONCLUSION

In this clinical sample of children with ASD, regression was diagnosed in a small percentage (4%). Those with regression had lower cognitive, language, and adaptive skills compared with those without regression. Rates of clinician-diagnosed regression referred for medical workup are significantly lower than prior estimates based on parent report.

Recognizing Psychosis in Autism Spectrum Disorder

There is strong evidence for the existence of a high comorbidity between autism and psychosis with percentages reaching up to 34. 8% and several significant implications for treatment and prognosis of these patients. However, the identification of comorbid psychosis in patients with Autism Spectrum Disorder represents a complex challenge from a psychopathological point of view, in particular in patients with greater deficits in verbal communication. Intercepting the onset of a psychotic breakdown in autism may be very difficult, both disorders in fact occur along a phenotypic continuum of clinical severity and in many cases, psychotic symptoms are present in an attenuated form. In this paper, we reviewed the available scientific literature about comorbidity between psychosis and autism, focusing our attention on four specific dimensions: delusions, hallucinations, negative symptoms, and clinical course. The aim of this paper is to provide clinical tools to identify these psychotic phenomena in autistic patients, even when they occur in their attenuated form.

Neonatal Imitation, Intersubjectivity, and Children With Atypical Development: Do Observations on Autism and Down Syndrome Change Our Understanding?

Almost all studies on neonatal imitation to date seem to have focused on typically developing children, and we thus lack information on the early imitative abilities of children who follow atypical developmental trajectories. From both practical and theoretical perspectives, these abilities might be relevant to study in children who develop a neuropsychiatric diagnosis later on or in infants who later show impaired ability to imitate. Theoretical in the sense that it will provide insight into the earliest signs of intersubjectivity—i.e., primary intersubjectivity—and how this knowledge might influence our understanding of children following atypical trajectories of development. Practical in the sense that it might lead to earlier detection of certain disabilities. In the present work, we screen the literature for empirical studies on neonatal imitation in children with an Autism spectrum disorder (ASD) or Down syndrome (DS) as well as present an observation of neonatal imitation in an infant that later was diagnosed with autism and a re-interpretation of previously published data on the phenomenon in a small group of infants with DS. Our findings suggest that the empirical observations to date are too few to draw any definite conclusions but that the existing data suggests that neonatal imitation can be observed both in children with ASD and in children with DS. Thus, neonatal imitation might not represent a useful predictor of a developmental deficit. Based on current theoretical perspectives advocating that neonatal imitation is a marker of primary intersubjectivity, we propose tentatively that an ability to engage in purposeful exchanges with another human being exists in these populations from birth.

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.

Autism Spectrum Disorder and Sleep

Children and adolescents with autism spectrum disorder (ASD) experience sleep disturbances, particularly insomnia, at rates much higher than the general population. Daytime behavioral problems and parental stress are associated with the resultant sleep deprivation. Behavioral interventions, parental education, and melatonin are effective treatments. The epidemiology of sleep disturbances in youth with ASD is reviewed in this article as well as the latest in treatments.

From Toddlerhood to Adolescence, Trajectories and Predictors of Outcome: Long-Term Follow-Up Study in Autism Spectrum Disorder

This study is one of a very few prospective long-term studies in autism spectrum disorder (ASD). The study compared outcome trajectories in three adolescent groups (T2): "best outcome" (BO, n = 11) did not meet cut-off points for ASD and IQ scores ≥85; high functioning (HF-ASD, n = 14); and lower functioning (LF-ASD, n = 43). Additionally, the study searched for characteristics at toddlerhood (T1) that may predict belonging to the above groups. The study included 68 adolescents (63 males) diagnosed with ASD at toddlerhood (mean age: 13:10 years), mean follow-up time was 11:7 years. Participants underwent comprehensive assessments at T1 and T2. Different trajectories were found for the three defined groups. The BO group improved significantly in cognitive ability, autism severity, and adaptive skills in comparison to no improvement for the LF-ASD group or partial progress for the HF-ASD group. At toddlerhood, better cognition and less severe autism social affect symptoms were generally associated with a better outcome. Early social behaviors including better "pointing," "facial expression directed to others," "showing," and "response to joint attention" were associated with membership in the BO group. In addition, the BO group had the lowest prevalence of significant T2 inattention and anxiety symptoms. No significant differences between the three outcome groups were noted in the birth and prevalence of medical problems. Higher cognitive ability and better T1 showing and pointing behaviors predicted better outcome. The study points to the change in autism severity over time and to the prognostic value of early developmental abilities, social engagement behaviors, and the existence of comorbidities. Autism Res 2020, 13: 1130-1143. © 2020 International Society for Autism Research and Wiley Periodicals LLC. LAY SUMMARY: This long-term study compared characteristics of toddlers diagnosed with autism spectrum disorder (ASD) in three outcome groups in adolescence: best outcome (BO-average IQ/not meeting criteria for ASD), high-functioning ASD, and low-functioning ASD (LF-ASD). At toddlerhood, the BO group displayed less severe autism symptoms, mostly in sharing interests, compared to the LF-ASD group. The BO group had fewer inattention and anxiety symptoms than the two ASD groups. Additionally, early cognitive level and social engagement behaviors predicted outcome in ASD.

Analysis of gut microbiome, nutrition and immune status in autism spectrum disorder: a case-control study in Ecuador

Most studies on autism spectrum disorder (ASD) risk factors have been conducted in developed countries where ethnicity and environment are different than in developing countries. We compared nutritional status, immune response and microbiota composition in mestizo children with ASD with matched controls in Ecuador. Twenty-five cases and 35 controls were matched by age, sex and school location. The prevalence of under- and overweight was higher in children with ASD. Nutritional differences were accompanied by abnormal food habits and more frequent gastrointestinal symptoms in children with ASD. Also, greater serum concentrations of TGF-β1 were observed in children with ASD. Finally, there was greater alpha diversity and abundance of Bacteroides (2 OTUs), Akkermansia, Coprococcus and different species of Ruminococcus in ASD children.

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.

Inferring Brain Signals Synchronicity from a Sample of EEG Readings

Inferring patterns of synchronous brain activity from a heterogeneous sample of electroencephalograms (EEG) is scientifically and methodologically challenging. While it is intuitively and statistically appealing to rely on readings from more than one individual in order to highlight recurrent patterns of brain activation, pooling information across subjects presents non-trivial methodological problems. We discuss some of the scientific issues associated with the understanding of synchronized neuronal activity and propose a methodological framework for statistical inference from a sample of EEG readings. Our work builds on classical contributions in time-series, clustering and functional data analysis, in an effort to reframe a challenging inferential problem in the context of familiar analytical techniques. Some attention is paid to computational issues, with a proposal based on the combination of machine learning and Bayesian techniques.

Regression in autism spectrum disorder: Reconciling findings from retrospective and prospective research

The way in which the behavioral manifestations of autism spectrum disorder (ASD) emerge in infancy is variable. Regression-loss of previously acquired skills-occurs in a subset of children. However, the etiology and significance of regression remains unclear. Until recently, investigation of regression relied on retrospective report by parents or examination of home videos from early in life. However, home videos and retrospective report of the nature and timing of regression, and association with factors such as illness or immunization, is potentially subject to bias. The advent of prospective studies of infant siblings at familial high-risk of ASD has the potential to document regression as it occurs. Recent research has suggested that subtle loss of skills occurs in a larger proportion of children with ASD than previously assumed; however, there are few reports of clear-cut regressions, such as that involving dramatic loss of language and other established skills, in the prospective literature. This could be because of the following: clear-cut regression occurs less commonly than parent report suggests, study design limits the potential to detect regression, or there are differences between multiplex and simplex families in the rate of de novo genetic mutations and therefore regression risk. This review will bring together literature from retrospective and prospective research and attempt to reconcile diverging findings, with a specific focus on methodological issues. Changing conceptualizations of regression will be discussed, as well as etiological factors that may be associated with regression. The main challenges that need to be addressed to measure regression in prospective studies will be set out. Autism Research 2018, 11: 1602-1620. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Regression-a loss of previously established skills-occurs in a subset of children with ASD. Parental recall is not always accurate but studying younger siblings of children with ASD, 10-20% of whom will develop ASD, should make it possible to measure regression as it occurs. Clear-cut regression, like loss of language, has not often been reported in infant sibling studies, but recent research suggests that gradual loss of social engagement might be more common. This review looks at the evidence for regression from infant sibling studies and asks how study design affects the likelihood of capturing regression.

[Age of diagnosis of autism spectrum disorder in children and factors influencing the age of diagnosis]

OBJECTIVE

To investigate the age of diagnosis of autism spectrum disorder (ASD) and the factors influencing the age of diagnosis in children.

METHODS

A retrospective analysis was performed for the clinical data of 1 691 children who visited in the Children's Hospital of Chongqing Medical University for the first time and were definitely diagnosed with ASD between February 2011 and July 2017. A multiple linear regression model was used to identify the factors influencing the age of diagnosis of ASD.

RESULTS

The ASD children had a mean age of 35±17 months (range 9-175 months) at diagnosis. Of all 1 691 children, the children who received a diagnosis of ASD at the age of 24-35 months accounted for the highest proportion (46.13%, 780/1 691), followed by those at the age of ≥36 months (33.41%, 565/1 691). The multiple linear regression analysis showed that the children who had language disorders or lived in the main urban area or whose parents had a high education level had a younger age at diagnosis than other children (P<0.05).

CONCLUSIONS

Most ASD children have an age of 24-35 months at diagnosis. The age of diagnosis of ASD is associated with children's symptoms, living area, and parents' education level.

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.

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.

Epilepsy in patients with autism: links, risks and treatment challenges

Autism is more common in people with epilepsy, approximately 20%, and epilepsy is more common in people with autism with reported rates of approximately 20%. However, these figures are likely to be affected by the current broader criteria for autism spectrum disorder (ASD), which have contributed to an increased prevalence of autism, with the result that the rate for ASD in epilepsy is likely to be higher and the figure for epilepsy in ASD is likely to be lower. Some evidence suggests that there are two peaks of epilepsy onset in autism, in infancy and adolescence. The rate of autism in epilepsy is much higher in those with intellectual disability. In conditions such as the Landau-Kleffner syndrome and nonconvulsive status epilepticus, the epilepsy itself may present with autistic features. There is no plausible mechanism for autism causing epilepsy, however. The co-occurrence of autism and epilepsy is almost certainly the result of underlying factors predisposing to both conditions, including both genetic and environmental factors. Conditions such as attention deficit hyperactivity disorder, anxiety and sleep disorders are common in both epilepsy and autism. Epilepsy is generally not a contraindication to treating these conditions with suitable medication, but it is important to take account of relevant drug interactions. One of the greatest challenges in autism is to determine why early childhood regression occurs in perhaps 25%. Further research should focus on finding the cause for such regression. Whether epilepsy plays a role in the regression of a subgroup of children with autism who lose skills remains to be determined.

Facilitating Autism Research

Early autism research focused on behavior and cognition. In recent decades, the pace of research has accelerated, and advances in imaging and genetics have allowed the accumulation of biological data. Nevertheless, a coherent picture of the syndrome at either phenotypic or biological level has not emerged. We see two fundamental obstacles to progress in basic understanding of autism. First, the two defining features (impairment in social interactions and communication, and restricted, repetitive behaviors and interests) are historically seen as integrally related. Others hold that these two major traits are fractionable and must be studied independently, casting doubt on autism as a coherent syndrome. Second, despite much recent research on brain structure and function, environmental factors, and genetics/genomics, findings on the biological level have not generally aligned well with those on the phenotypic level. In the first two sections, we explore these challenges, and in the third section, we review approaches that may facilitate progress, such as (1) including in studies all individuals defined by social impairment without regard to repetitive behaviors, (2) forming narrowly defined subtypes by thorough characterization on specific features, both diagnostic and non-diagnostic, (3) focusing on characteristics that may be relatively robust to environmental influence, (4) studying children as early as possible, minimizing environmental influence, and including longitudinal course as an important part of the phenotype, (5) subtyping by environmental risk factors, (6) distinguishing between what participants can do and what they typically do, and (7) aggregating large data sets across sites. (JINS, 2017, 23, 903-915).

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.

Autism Spectrum Disorders (ASD) in Blind Children: Very High Prevalence, Potentially Better Outlook

Autism spectrum disorders affected 19 of 38 unselected children at a school for the blind in Cordoba, Argentina. Autism was linked to total congenital blindness, not blindness' etiology, acquired or incomplete blindness, sex, overt brain damage, or socioeconomic status. Autism "recovery," had occurred in 4 verbal children. Congenital blindness causes profoundly deviant sensory experience and massive reorganization of brain connectivity. Its ≥ 30 times greater prevalence than in sighted children suggests a distinct pathogenesis. Unawareness of autism's high prevalence in blind individuals includes blindness' rarity, misunderstanding of autism as "disease" rather than dimensional behavioral diagnosis, reluctance to diagnose it in blind children, and ignorance of its potentially more favorable outcome. Future investigation may suggest interventions to prevent or mitigate it.

Specific Medical Conditions Are Associated with Unique Behavioral Profiles in Autism Spectrum Disorders

Autism spectrum disorder (ASD) is a heterogeneous group of disorders which occurs with numerous medical conditions. In previous research, subtyping in ASD has been based mostly on cognitive ability and ASD symptom severity. The aim of the current study was to investigate whether specific medical conditions in ASD are associated with unique behavioral profiles. The medical conditions included in the study were macrocephaly, microcephaly, developmental regression, food selectivity, and sleep problems. The behavioral profile was composed of cognitive ability, adaptive skills, and autism severity, and was examined in each of the aforementioned medical conditions. The study population included 1224 participants, 1043 males and 181 females (M:F ratio = 5.8:1) with a mean age of 49.9 m (SD = 29.4) diagnosed with ASD using standardized tests. Groups with and without the specific medical conditions were compared on the behavioral measures. Developmental regression was present in 19% of the population and showed a more severe clinical presentation, with lower cognitive abilities, more severe ASD symptoms, and more impaired adaptive functioning. Microcephaly was observed in 6.3% of the population and was characterized by a lower cognitive ability and more impaired adaptive functioning in comparison to the normative head circumference (HC) group. Severe food selectivity was found in 9.8% and severe sleep problems in 5.1% of the ASD population. The food selectivity and sleep problem subgroups, both showed more severe autism symptoms only as described by the parents, but not per the professional assessment, and more impaired adaptive skills. Macrocephaly was observed in 7.9% of the ASD population and did not differ from the normative HC group in any of the examined behavioral measures. Based on these findings, two unique medical-behavioral subtypes in ASD that affect inherited traits of cognition and/or autism severity were suggested. The microcephaly phenotype occurred with more impaired cognition and the developmental regression phenotype with widespread, more severe impairments in cognition and autism severity. In contrast, severe food selectivity and sleep problems represent only comorbidities to ASD that affect functioning. Defining specific subgroups in ASD with a unique biological signature and specific behavioral phenotypes may help future genetic and neuroscience research.

Reported History of Developmental Regression and Restricted, Repetitive Behaviors in Children with Autism Spectrum Disorders

OBJECTIVE

Previous research on developmental regression in youth with autism spectrum disorders (ASD) has often been limited by the definition, assessment, and methodology used to evaluate and describe regression. This study sought to overcome these limitations by examining the prevalence, timing, and correlates of documented cases of developmental regression in a large, epidemiological sample of youth with ASD.

METHOD

Utilizing a population-based surveillance methodology, this study includes 862 youth with ASD identified through abstraction and clinician record review.

RESULTS

Approximately 21% of the sample had developmental regression documented in their medical or educational records with the mean age of regression being 24.2 ± 14.3 months. Youth with ASD and a history of regression were more likely to have comorbid intellectual disability, a prior community diagnosis of ASD, and be eligible for educational services as a student with autism. Youth with a documented history of regression also had higher rates of restricted, repetitive behaviors, such as stereotyped speech, nonfunctional routines/rituals, and sensory interests.

CONCLUSION

Results suggest that youth with a history of regression are not only more likely to have comorbid intellectual disability but are also are more likely to have been previously diagnosed with ASD in the community, suggesting that development regression may play an important role in identifying children who are at the risk for ASD and need evaluation. Higher rates of restricted, repetitive behaviors in youth with a documented history of regression may also provide important insights into the relationship between ASD and developmental regression.

Factors Affecting Age at ASD Diagnosis in UK: No Evidence that Diagnosis Age has Decreased Between 2004 and 2014

Clinical initiatives have aimed to reduce the age at ASD diagnosis in the UK. This study investigated whether the median age at diagnosis in childhood has reduced in recent years, and identified the factors associated with earlier diagnosis in the UK. Data on 2134 children with ASD came from two large family databases. Results showed that the age of ASD diagnosis has not decreased. The median age of diagnosis of all ASDs was 55 months. Factors associated with earlier age of diagnosis were autism diagnosis (compared with other ASD), language regression, language delay, lower socioeconomic status, and greater degree of support required. Effective clinical strategies are needed to identify children with characteristics that have in the past delayed ASD diagnosis.

Diurnal Salivary Cortisol and Regression Status in MECP2 Duplication Syndrome

MECP2 duplication syndrome is an X-linked genomic disorder that is characterized by infantile hypotonia, intellectual disability, and recurrent respiratory infections. Regression affects a subset of individuals, and the etiology of regression has yet to be examined. In this study, alterations in the hypothalamus-pituitary-adrenal axis, including diurnal patterns in salivary cortisol, were examined in 4 males with MECP2 duplication syndrome who had regression and 4 males with the same syndrome without regression (aged 3-22 years). Individuals who had experienced regression do not exhibit typical diurnal cortisol rhythms, and their profiles were flatter through the day. In contrast, individuals with MECP2 duplication syndrome who had not experienced regression showed more typical patterns of higher cortisol levels in the morning with linear decreases throughout the day. This study is the first to suggest a link between atypical diurnal cortisol rhythms and regression status in MECP2 duplication syndrome and may have implications for treatment.

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.

Social visual engagement in infants and toddlers with autism: early developmental transitions and a model of pathogenesis

Efforts to determine and understand the causes of autism are currently hampered by a large disconnect between recent molecular genetics findings that are associated with the condition and the core behavioral symptoms that define the condition. In this perspective piece, we propose a systems biology framework to bridge that gap between genes and symptoms. The framework focuses on basic mechanisms of socialization that are highly-conserved in evolution and are early-emerging in development. By conceiving of these basic mechanisms of socialization as quantitative endophenotypes, we hope to connect genes and behavior in autism through integrative studies of neurodevelopmental, behavioral, and epigenetic changes. These changes both lead to and are led by the accomplishment of specific social adaptive tasks in a typical infant's life. However, based on recent research that indicates that infants later diagnosed with autism fail to accomplish at least some of these tasks, we suggest that a narrow developmental period, spanning critical transitions from reflexive, subcortically-controlled visual behavior to interactional, cortically-controlled and social visual behavior be prioritized for future study. Mapping epigenetic, neural, and behavioral changes that both drive and are driven by these early transitions may shed a bright light on the pathogenesis of autism.

Regression in autism spectrum disorders

Since the Journal of Paediatrics and Child Health was first published, there has been substantial change in the field of autism spectrum disorders (ASDs) with an exponential increase in the amount of funded and published research. In this paper, we focus on regression in children with ASD, a phenomenon that remains poorly understood. We discuss the implications of what we know about regression in ASD for the way we think about ASD more broadly and for paediatric practice.

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.

Exposure to Air Pollution From Traffic and Neurodevelopmental Disorders in Swedish Twins

Background: Recent studies have reported associations between air pollution exposure and neurodevelopmental disorders in children, but the role of pre- and postnatal exposure has not been elucidated. Aim: We aimed to explore the risk for autism spectrum disorders (ASD) and attention-deficit hyperactivity disorder (ADHD) among children in relation to pre- and postnatal exposure to air pollution from road traffic. Methods: Parents of 3,426 twins born in Stockholm during 1992–2000 were interviewed, when their children were 9 or 12 years old, for symptoms of neurodevelopmental disorders. Residence time-weighted concentrations of particulate matter with a diameter <10 μm (PM10) and nitrogen oxides (NOx) from road traffic were estimated at participants’ addresses during pregnancy, the first year, and the ninth year of life using dispersion modeling, controlling for seasonal variation. Multivariate regression models were used to examine the association between air pollution exposure and neurodevelopmental outcomes, adjusting for potential confounding factors. Results: No clear or consistent associations were found between air pollution exposure during any of the three time windows and any of the neurodevelopmental outcomes. For example, a 5–95% difference in exposure to NOx during pregnancy was associated with odds ratios (ORs) of 0.92 (95% confidence interval (CI): 0.44–1.96) and 0.90 (95% CI: 0.58–1.40) for ASD and ADHD respectively. A corresponding range in exposure to PM10 during pregnancy was related to ORs of 1.01 (95% CI: 0.52–1.96) and 1.00 (95% CI: 0.68–1.47) for ASD and ADHD. Conclusions: Our data do not provide support for an association between pre- or postnatal exposure to air pollution from road traffic and neurodevelopmental disorders in children.

Patterns of skill attainment and loss in young children with autism

The purpose of this study was to extend the literature on the ontogeny of autism spectrum disorder (ASD) by examining early attainment and loss of specific sociocommunicative skills in children with autism (AUT; n = 125), pervasive developmental disorder not otherwise specified (PDD-NOS; n = 42), nonspectrum developmental delays (n = 46), and typical development (n = 31). The ages of skill attainment and loss were obtained from a caregiver interview. The findings indicated that children with AUT, PDD-NOS, and developmental delays diverged from typically developing children in attainment of sociocommunicative skills early in the first year of life. Loss of at least one skill was reported in a majority of children with AUT and PDD-NOS. Significant delays in attainment of skills were also reported in children who lost skills. The wide variation in skill attainment and loss reported across children indicates that symptom onset and regression may be best represented continuously, with at least some early delay and loss present for a great majority of children with ASD.

Resting state EEG abnormalities in autism spectrum disorders

Autism spectrum disorders (ASD) are a group of complex and heterogeneous developmental disorders involving multiple neural system dysfunctions. In an effort to understand neurophysiological substrates, identify etiopathophysiologically distinct subgroups of patients, and track outcomes of novel treatments with translational biomarkers, EEG (electroencephalography) studies offer a promising research strategy in ASD. Resting-state EEG studies of ASD suggest a U-shaped profile of electrophysiological power alterations, with excessive power in low-frequency and high-frequency bands, abnormal functional connectivity, and enhanced power in the left hemisphere of the brain. In this review, we provide a summary of recent findings, discuss limitations in available research that may contribute to inconsistencies in the literature, and offer suggestions for future research in this area for advancing the understanding of ASD.

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.

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.

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.

Progress in understanding autism: 2007-2010

Scientific progress is discussed in relation to clinical issues; genetic issues; environmental issues; and the state of play on psychological treatments. It is concluded that substantial gains in knowledge have been achieved during the last 3 years, and there have been some unexpected findings, but major puzzles remain. We should be hopeful of ever greater gains in the years ahead, but both prevention and cure remain elusive.

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.