Does the cognitive architecture of simplex and multiplex ASD families differ?

Examination of Clinical and Assessment Type Differences Between Toddlers with ASD from Multiplex and Simplex Families

Few studies have examined differences in autism spectrum disorder (ASD) phenotype between children from multiplex and simplex families at the time of diagnosis. The present study used an age- and gender-matched, community-based sample (n = 105) from the southwestern United States to examine differences in ASD symptom severity, cognitive development, and adaptive functioning. No significant differences between children from multiplex and simplex families were observed. Exploratory analysis revealed that parents underreported receptive and expressive language and fine motor skills compared to professional observation, especially among children from multiplex families. These findings suggest that diagnosticians may need to consider family structure when choosing and interpreting assessments of receptive language, expressive language, and fine motor skills.

Heterogeneity of autism symptoms in community-referred infants and toddlers at elevated or low familial likelihood of autism

Evidence suggests autistic individuals at elevated familial likelihood of autism spectrum disorder (by virtue of having an autistic sibling) have stronger cognitive abilities on average than autistic individuals with no family history of the condition, who have a low familial likelihood of autism. Investigating phenotypic differences between community-referred infants and toddlers with autism symptoms at elevated or low familial likelihood of autism may provide important insight into heterogeneity in the emerging autism phenotype. This study compared behavioral, cognitive, and language abilities of community-referred infants and toddlers with confirmed autism symptoms at elevated (EL) or low familial likelihood of autism (LL). Participants were 121 children aged 12 to 36 months who participated in two larger randomized trials of parent-mediated interventions for children with autism symptoms. Behavioral phenotypes were compared across three groups: children with at least one autistic sibling (EL-Sibs, n = 30), those with at least one older, non-autistic sibling and no family history of autism (LL-Sibs, n = 40), and first-born children with no family history of autism (LL-FB, n = 51). EL-Sibs had less severe autism symptoms and stronger cognitive abilities than children in LL groups. While the rate of receptive language delay was similar across groups, the rate of expressive language delay was markedly lower among EL-Sibs. After controlling for age and nonverbal cognitive ability, EL-Sibs were significantly less likely to present with expressive language delay than LL-Sibs. Familial likelihood of autism may play an important role in shaping the emerging autism phenotype in infancy and toddlerhood.

Evaluating causal psychological models: A study of language theories of autism using a large sample

We used a large convenience sample (n = 22,223) from the Simons Powering Autism Research (SPARK) dataset to evaluate causal, explanatory theories of core autism symptoms. In particular, the data-items collected supported the testing of theories that posited altered language abilities as cause of social withdrawal, as well as alternative theories that competed with these language theories. Our results using this large dataset converge with the evolution of the field in the decades since these theories were first proposed, namely supporting primary social withdrawal (in some cases of autism) as a cause of altered language development, rather than vice versa. To accomplish the above empiric goals, we used a highly theory-constrained approach, one which differs from current data-driven modeling trends but is coherent with a very recent resurgence in theory-driven psychology. In addition to careful explication and formalization of theoretical accounts, we propose three principles for future work of this type: specification, quantification, and integration. Specification refers to constraining models with pre-existing data, from both outside and within autism research, with more elaborate models and more veridical measures, and with longitudinal data collection. Quantification refers to using continuous measures of both psychological causes and effects, as well as weighted graphs. This approach avoids "universality and uniqueness" tests that hold that a single cognitive difference could be responsible for a heterogeneous and complex behavioral phenotype. Integration of multiple explanatory paths within a single model helps the field examine for multiple contributors to a single behavioral feature or to multiple behavioral features. It also allows integration of explanatory theories across multiple current-day diagnoses and as well as typical development.

Complex response inhibition and cognitive flexibility in school-aged Cypriot-Greek-speaking children who stutter

PURPOSE

Over the last few years, research findings have suggested limitations in executive function (EF) of children who stutter (CWS) with the evidence being more consistent in studies with preschoolers (3-6  years old) than in studies with school-aged children (6-12  years old). The purpose of the current study was to assess complex response inhibition and cognitive flexibility in school-aged CWS and their non-stuttering peers.

METHODS

Participants, 19 CWS (mean age = 7.58  years, range 6.08-9.17) and 19 age-and gender-matched children who do not stutter (CWNS; mean age = 7.58  years, range 6.08-9.33), completed a visual task consisting of three task blocks. Analyses were based on response times and error percentages during the different task blocks.

RESULTS

All participants showed expected performance-costs in task block comparisons targeting complex response inhibition and cognitive flexibility. Significant group differences were found in measures of cognitive flexibility with CWS performing slower compared to CWNS (p = 0.02). Additionally, significant block × group interactions demonstrated that CWS, compared to CWNS, slowed down more (i.e., higher performance-cost) under both complex response inhibition (p = 0.049) and cognitive flexibility task conditions (p = 0.04 for no-set-shifting and p = 0.02 for set-shifting).

CONCLUSION

These results are in line with some of the previous findings in school-aged CWS and suggest that CWS present lower performance in complex response inhibition and cognitive flexibility task conditions when compared to their non-stuttering peers.

Environmental Influences Measured by Epigenetic Clock and Vulnerability Components at Birth Impact Clinical ASD Heterogeneity

Although Autism Spectrum Disorders (ASD) is recognized as being heavily influenced by genetic factors, the role of epigenetic and environmental factors is still being established. This study aimed to identify ASD vulnerability components based on familial history and intrauterine environmental stress exposure, explore possible vulnerability subgroups, access DNA methylation age acceleration (AA) as a proxy of stress exposure during life, and evaluate the association of ASD vulnerability components and AA to phenotypic severity measures. Principal Component Analysis (PCA) was used to search the vulnerability components from 67 mothers of autistic children. We found that PC1 had a higher correlation with psychosocial stress (maternal stress, maternal education, and social class), and PC2 had a higher correlation with biological factors (psychiatric family history and gestational complications). Comparing the methylome between above and below PC1 average subgroups we found 11,879 statistically significant differentially methylated probes (DMPs, p < 0.05). DMPs CpG sites were enriched in variably methylated regions (VMRs), most showing environmental and genetic influences. Hypermethylated probes presented higher rates in different regulatory regions associated with functional SNPs, indicating that the subgroups may have different affected regulatory regions and their liability to disease explained by common variations. Vulnerability components score moderated by epigenetic clock AA was associated with Vineland Total score (p = 0.0036, adjR² = 0.31), suggesting risk factors with stress burden can influence ASD phenotype.

Developmental Trajectories of Infants With Multiplex Family Risk for Autism: A Baby Siblings Research Consortium Study

Importance

Autism spectrum disorder (ASD) is a neurodevelopmental disorder associated with different genetic etiologies. Prospective examination of familial-risk infants informs understanding of developmental trajectories preceding ASD diagnosis, potentially improving early detection.

Objective

To compare outcomes and trajectories associated with varying familial risk for ASD across the first 3 years of life.

Design, Setting, and Participants

This longitudinal, prospective cohort study used data from 11 sites in the Baby Siblings Research Consortium database. Data were collected between 2003 and 2015. Infants who were younger siblings of children with ASD were followed up for 3 years. Analyses were conducted in April 2018. Of the initial 1008 infants from the database, 573 were removed owing to missing necessary data, diagnostic discrepancies, or only having 1 older sibling.

Exposures

Number of siblings with ASD.

Main Outcomes and Measures

Outcomes included ASD symptoms, cognitive abilities, and adaptive skills. Diagnosis (ASD or no ASD) was given at 36-month outcome. The no-ASD group was classified as atypical (developmental delays and/or social-communication concerns) or typical for some analyses. Generalized linear mixed models examined developmental trajectories by ASD outcome and familial-risk group.

Results

In the 435 analyzed participants (age range at outcome, 32-43 months; 246 male [57%]), 355 (82%) were from single-incidence families (1 sibling with ASD and ≥1 sibling without ASD) and 80 (18%) were from multiplex families (≥2 siblings with ASD). There were no significant group differences in major demographics. Children from multiplex families were more likely than those from single-incidence families to be classified as having ASD (29 of 80 [36%] vs 57 of 355 [16%]; 95% CI, 9%-31%; P < .001) and less likely as typical (26 of 80 [33%] vs 201 of 355 [57%]; 95% CI, -36% to -13%; P < .001), with similar rates of atypical classifications (25 of 80 [31%] vs 97 of 355 [27%]; 95% CI, -7% to 15%; P = .49). There were no differences in ASD symptoms between multiplex and single-incidence groups after controlling for ASD outcome (95% CI, -0.02 to 0.20; P = .18). During infancy, differences in cognitive and adaptive abilities were observed based on ASD outcome in the single-incidence group only. At 36 months, the multiplex/no-ASD group had lower cognitive abilities than the single-incidence/no-ASD group (95% CI, -11.89 to -2.20; P = .02), and the multiplex group had lower adaptive abilities than individuals in the single-incidence group after controlling for ASD outcome (95% CI, -9.01 to -1.48; P = .02).

Conclusions and Relevance

Infants with a multiplex family history of ASD should be monitored early and often and referred for early intervention at the first sign of concern. Direct examination of genetic contributions to neurodevelopmental phenotypes in infants with familial risk for ASD is needed.

Research Review: Outcomes of 24- to 36-month-old children with autism spectrum disorder vary by ascertainment strategy: a systematic review and meta-analysis

BACKGROUND

Despite widespread recommendations for early surveillance of risk for autism spectrum disorder (ASD), no research to date has shown that early surveillance leads to better clinical outcomes. Preliminary research has suggested that children with ASD ascertained via prospective follow-up have better outcomes than those ascertained via community referral. Because prospective studies include early surveillance, by comparing outcomes of children with ASD across ascertainment strategies, we may gain insight into the effects of early surveillance relative to its absence.

METHODS

A systematic review was conducted to identify studies reporting outcomes of 24- to 36-month-olds with ASD ascertained via prospective follow-up, community referral, or universal screening. A meta-analysis using a random effects model was used to calculate overall effect size estimates for developmental level and symptom severity across ascertainment cohorts.

RESULTS

Eleven prospective, ten community referral, and eight universal screening studies were identified, reporting on 1,658 toddlers with ASD. We found no differences in outcomes between community referral and universal screening studies. Relative to both, prospective studies reported significantly higher developmental levels and lower symptom severities.

CONCLUSIONS

Outcomes of young children with ASD ascertained via prospective follow-up are better than those of children with ASD recruited via community referral or universal screening. Although we discuss why sampling bias is not likely the driving force behind these findings, we cannot rule out the possibility that sampling bias contributes to the observed differences; future studies should probe the effects of sociodemographic variables on clinical outcomes as a function of ascertainment strategy. This limitation notwithstanding, our results raise the possibility that prospective follow-up may confer a 'surveillance effect' that contributes to improved developmental and diagnostic outcomes in children with ASD. Future research should test this hypothesis and determine the specific mechanism by which surveillance may improve outcomes.

Differences in Cognition and Behaviour in Multiplex and Simplex Autism: Does Prior Experience Raising a Child with Autism Matter?

Previous research has found multiplex (MPX) children have an advantage in cognition compared to simplex (SPX) children. However, MPX parent's previous experience with older diagnosed siblings has not been considered. We used a large database sample to investigate the MPX advantage and contribution of birth order. Children from the Autism Genetic Resource Exchange (AGRE) were stratified into first- (MPX¹, n  = 152) and second-affected MPX (MPX², n  = 143), SPX (n  = 111), and only-child SPX (SPX^OC, n  = 23) groups. Both MPX groups had higher cognitive scores compared to SPX groups, with no differences between MPX¹ and MPX² groups. No differences were found for autism symptoms or adaptive behaviour. These results suggest parent experience due to birth order is an unlikely contributor to the MPX cognitive advantage.

Theory of Mind Performance in Broad Autism Phenotype Groups: Between-Group Differences and Predictor Variables

Investigated between-group differences in cognitive/affective theory of mind (ToM) and predictors of cognitive ToM both within broad autism phenotype/non (BAP/Non-BAP) groups as well as across the sample. The BAP group (n = 45) performed worse than the Non-BAP group (n = 102) on the unexpected outcomes test (UOT), but groups were similar regarding reading the mind in the eyes test (RMET). Stepwise regression indicated RMET best predicted UOT for the BAP group; block design best predicted UOT in the Non-BAP group. BAP traits did not mediate the relation of RMET to UOT performance. While RMET and UOT appear similarly related in BAP/Non-BAP samples, use of emotion recognition abilities in a cognitive ToM task may reflect over-reliance on this skill in the BAP.

Cognitive and behavioral differences in toddlers with autism spectrum disorder from multiplex and simplex families

Prospective, longitudinal designs utilizing "high-risk" infant siblings of children diagnosed with Autism Spectrum Disorder (ASD-sibs) have provided unique and valuable insights regarding the early ASD phenotype. However, it remains unclear whether these cases are representative of all children with ASD. The objective in the present study was to investigate whether the early development of toddlers with ASD from multiplex (MPX) families, who have an affected older sibling, is similar or different to toddlers with ASD from simplex (SPX) families, where there is no affected sibling. A further aim was to examine patterns of association between autism symptom severity and cognitive functioning within each group to inform possible mechanisms for group similarities/differences. Behavioral and cognitive assessment data from a sample of toddlers with ASD was utilized, comprising 45 MPX, 127 first-born SPX, and 72 later-born SPX toddlers. Participants in the MPX group had significantly higher developmental quotients on the Mullen Scales of Early Learning compared to those in the SPX groups, who did not differ from each other. However, all three groups were similar on their autism severity scores (measured using the Autism Diagnostic Observation Schedule and the Autism Diagnostic Interview), and the pattern of relationships between cognitive ability and autism symptom severity. The results suggest that caution be exercised in generalizing findings from ASD-sib samples to other samples of children with ASD. The higher cognitive abilities in the MPX group, in addition to biological differences, may also be an outcome of family environmental factors, which deserves further investigation. Autism Research 2019, 12: 682-693. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: We sought to establish whether toddlers with autism from families where there is more than one affected child, called multiplex families, are different to children from simplex families, where there is only one affected child, and no other members within the immediate family with an autism diagnosis. We found that while toddlers from multiplex families were similar to those from simplex families in their autism symptoms, they were more developmentally advanced than children in the latter group.

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.

Alexithymia, depression and anxiety in parents of children with neurodevelopmental disorder: Comparative study of autistic disorder, pervasive developmental disorder not otherwise specified and attention deficit-hyperactivity disorder

BACKGROUND

Recent studies have shown that individuals with neurodevelopmental disorders and their relatives have problems expressing and recognizing emotions, but there is a lack of studies on alexithymia, and the relationship between parental alexithymia and depression-anxiety symptoms in these groups. The aim of this study was therefore to measure alexithymia, depression, and anxiety levels in parents of children with pervasive developmental disorders and attention deficit-hyperactivity disorder (ADHD), and determine whether there is a positive correlation between the child's neurodevelopmental problem severity and parent scores.

METHODS

Parents of 29 autistic disorder (AD), 28 pervasive developmental disorder not otherwise specified (PDD-NOS) and 29 ADHD children were recruited into the study, and completed a demographic information form, as well as the Toronto Alexithymia Scale (TAS-20), Beck Depression Inventory, and State-Trait Anxiety Inventory.

RESULTS

Alexithymia symptoms were higher in parents of children with AD than in others but unexpectedly, also these symptoms were higher in ADHD parents than in PDD-NOS groups. In addition, there were unexpected differences according to alexithymia subtype, while only the difference in maternal TAS-1 scores (difficulty in describing feelings) were statistically significant. Parental depression and state anxiety scores were increased as the child's symptom severity increased, but trait anxiety symptoms were higher in the AD and ADHD group than in the PDD-NOS group. In all groups, maternal depression and anxiety scores were higher than paternal scores, and differences were significant for depression and anxiety types in AD, and for only anxiety types in ADHD parents. The AD group had the strongest correlation between parental depression-anxiety and alexithymia.

CONCLUSION

The possibility of alexithymia, depression and anxiety should be kept in mind when working with parents of children with neurodevelopmental disorders.

Brief Report: Characteristics of preschool children with ASD vary by ascertainment

Prospective studies of infant siblings of children diagnosed with autism spectrum disorder (ASD) provide a unique opportunity to characterize ASD as it unfolds. A critical question that remains unanswered is whether and how these children with ASD resemble other children identified from the community, including those with no family history. The purpose of this study was to compare clinical characteristics of children with ASD identified by each method (n = 86 per group), drawn from two Canadian longitudinal research cohorts. Children ascertained from a prospective cohort were less severely affected and included a larger proportion of girls, compared to the clinically referred sample. These results may have important implications for conclusions drawn from studies of high-risk and clinically referred cohorts.

Executive functioning and local-global visual processing: candidate endophenotypes for autism spectrum disorder?

BACKGROUND

Heterogeneity within autism spectrum disorder (ASD) hampers insight in the etiology and stimulates the search for endophenotypes. Endophenotypes should meet several criteria, the most important being the association with ASD and the higher occurrence rate in unaffected ASD relatives than in the general population. We evaluated these criteria for executive functioning (EF) and local-global (L-G) visual processing.

METHODS

By administering an extensive cognitive battery which increases the validity of the measures, we examined which of the cognitive anomalies shown by ASD probands also occur in their unaffected relatives (n = 113) compared to typically developing (TD) controls (n = 100). Microarrays were performed, so we could exclude relatives from probands with a de novo mutation in a known ASD susceptibility copy number variant, thus increasing the probability that genetic risk variants are shared by the ASD relatives. An overview of studies investigating EF and L-G processing in ASD relatives was also provided.

RESULTS

For EF, ASD relatives - like ASD probands - showed impairments in response inhibition, cognitive flexibility and generativity (specifically, ideational fluency), and EF impairments in daily life. For L-G visual processing, the ASD relatives showed no anomalies on the tasks, but they reported more attention to detail in daily life. Group differences were similar for siblings and for parents of ASD probands, and yielded larger effect sizes in a multiplex subsample. The group effect sizes for the comparison between ASD probands and TD individuals were generally larger than those of the ASD relatives compared to TD individuals.

CONCLUSIONS

Impaired cognitive flexibility, ideational fluency and response inhibition are strong candidate endophenotypes for ASD. They could help to delineate etiologically more homogeneous subgroups, which is clinically important to allow assigning ASD probands to different, more targeted, interventions.