Gender and age differences in the core triad of impairments in autism spectrum disorders: a systematic review and meta-analysis

Relationship between gray matter structure and age in children and adolescents with high-functioning autism spectrum disorder

Objective

The present study used magnetic resonance imaging to investigate the difference in the relationship between gray matter structure and age in children and adolescents with autism spectrum disorder (ASD) and typically developing (TD) subjects.

Methods

After screening T1 structural images from the Autism Brain Imaging Data Exchange (ABIDE) database, 111 children and adolescents (7-18 years old) with high-functioning ASD and 151 TD subjects matched for age, sex and full IQ were included in the current study. By using the voxel-based morphological analysis method, gray matter volume/density (GMV/GMD) maps were obtained for each participant. Then, a multiple regression analysis was performed for ASD and TD groups, respectively to estimate the relationship between GMV/GMD and age with gender, education, site, and IQ scores as covariates. Furthermore, a z-test was used to compare such relationship difference between the groups.

Results

Results showed that compared with TD, the GMD of ASD showed stronger positive correlations with age in the prefrontal cortex, and a stronger negative correlation in the left inferior parietal lobule, and a weaker positive correlation in the right inferior parietal lobule. The GMV of ASD displayed stronger positive correlations with age in the prefrontal cortex and cerebellum.

Conclusion

These findings may provide evidence to support that the brain structure abnormalities underlying ASD during childhood and adolescence may differ from each other.

Measurement invariance of the Autism Impact Measure (AIM) across sex in children with autism spectrum disorder

Measurement invariance, or the degree to which an instrument measures constructs consistently across subgroups, is critical for appropriate interpretations of measures. Given sex differences in the phenotypic and clinical presentation of autism spectrum disorder (ASD), it is particularly important to examine measurement invariance in autism instruments to ensure that ASD measures are not biased toward the more common male ASD phenotype. This study represents an important preliminary investigation evaluating the measurement equivalence of the Autism Impact Measure (AIM) across children and adolescents with ASD. The results indicated that the AIM demonstrated measurement invariance at the configural, metric, and scalar levels across sex in all five domains, including Repetitive Behavior, Communication, Atypical Behavior, Social Reciprocity, and Peer Interaction. These results suggest that ASD core symptoms assessed by the AIM were similar among male and female groups. In addition, the latent means for all five factors were not statistically significantly different across sex groups, revealing no systematic differences on any of the AIM subscales for males and females. Overall, this study showed that the AIM detects core ASD symptoms across all five areas equivalently in males and females and is not biased toward males with ASD.

Intellectual disabilities moderate sex/gender differences in autism spectrum disorder: a systematic review and meta-analysis

BACKGROUND

Girls/women with autism spectrum disorder (ASD) are suggested to exhibit different symptom profiles than boys/men with ASD. Accumulating evidence suggests that intellectual disability (ID) may affect sex/gender differences in ASD. However, a systematic review and meta-analysis on this topic is missing.

METHODS

Two databases (MEDLINE and PsycINFO) were used to search for studies reporting sex/gender differences (girls/women versus boys/men) in social communication and interaction, restrictive and repetitive behaviour and interests (RRBIs), sensory processing, and linguistic and motor abilities in ASD. The final sample consisted of 79 studies. The meta-analysis was performed with Review Manager using a random-effects model. Participants with ASD without and with ID were analysed as separate subgroups, and the effects in these two subgroups were also compared with each other.

RESULTS

Girls/women with ASD without ID displayed fewer RRBIs, more sensory symptoms and less problems in linguistic abilities than their boys/men counterparts. In contrast, girls/women with ASD with ID displayed more social difficulties and RRBIs, poorer linguistic abilities and more motor problems than boys/men with ASD with ID. Comparisons of groups of participants with ASD without ID versus participants with ASD with ID confirmed differences in sex/gender effects on social difficulties, sensory processing, linguistic abilities and motor abilities.

CONCLUSIONS

Our results clearly suggest that the female phenotype of ASD is moderated by ID. Among individuals with ASD with ID, girls/women seem to be more severely affected than boys/men, whereas among individuals with ASD without ID, girls/women with ASD may have less symptoms than boys/men. Such phenotypic differences could be a potential cause of underrecognition of girls/women with ASD, and it is also possible that observed phenotypic differences may reflect underdiagnosing of girls/women with ASD.

Sex Differences in Neurodevelopmental Disorders: A Key Role for the Immune System

Sex differences are prominent defining features of neurodevelopmental disorders. Understanding the sex biases in these disorders can shed light on mechanisms leading to relative risk and resilience for the disorders, as well as more broadly advance our understanding of how sex differences may relate to brain development. The prevalence of neurodevelopmental disorders is increasing, and the two most common neurodevelopmental disorders, Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) exhibit male-biases in prevalence rates and sex differences in symptomology. While the causes of neurodevelopmental disorders and their sex differences remain to be fully understood, increasing evidence suggests that the immune system plays a critical role in shaping development. In this chapter we discuss sex differences in prevalence and symptomology of ASD and ADHD, review sexual differentiation and immune regulation of neurodevelopment, and discuss findings from human and rodent studies of immune dysregulation and perinatal immune perturbation as they relate to potential mechanisms underlying neurodevelopmental disorders. This chapter will give an overview of how understanding sex differences in neuroimmune function in the context of neurodevelopmental disorders could lend insight into their etiologies and better treatment strategies.

Structural and Pragmatic Language Impairments in Children Evaluated for Autism Spectrum Disorder (ASD)

Pragmatic language impairments are common in neurodevelopmental disorders, especially in autism spectrum disorder (ASD). The relationship between structural language skills and pragmatic competence in children with autistic symptoms, however, is largely unknown. We investigated this relationship based on the Children's Communication Checklist-2 and early language delay among children (N = 177, 19% females) clinically evaluated for ASD, differentiated into ASD (n = 148) and non-ASD (n = 29). Structural language deficits were common and associated with reduced pragmatic competence in both groups. Pragmatic language impairments were most profound in children with ASD. Early language delay and structural language deficits were less common in females. Our findings suggest that assessment of structural language skills should be included in the evaluation of children with suspected ASD.

Gendered play behaviours in autistic and non-autistic children: A population-based cohort study

LAY ABSTRACT

Non-autistic children tend to show gendered patterns of play behaviours - boys are more likely to play with 'masculine' toys, and girls are more likely to play with 'feminine' toys. However, little is known about whether autistic children follow these patterns as well. We looked at the masculinity and femininity of autistic and non-autistic children's play behaviours at multiple time points. Parents reported their children's play behaviours at ages 30, 42 and 57 months, and children reported their own play behaviours at 8 years old. We found no difference between autistic and non-autistic girls, who both showed more feminine play behaviours as they got older. Autistic boys' play behaviours were reported as less masculine than non-autistic boys at 42 and 57 months, and at 8 years old. We also found that non-autistic boys' play tended to become more masculine as they got older, but this was not the case for autistic boys. Our findings suggest that differences in autistic and non-autistic boys' play behaviours may develop at around 42 months old.

Characterizing the ASD-ADHD phenotype: measurement structure and invariance in a clinical sample

BACKGROUND

Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) have considerable overlap, supporting the need for a dimensional framework that examines neurodevelopmental domains which cross traditional diagnostic boundaries. In the following study, we use factor analysis to deconstruct the ASD-ADHD phenotype into its underlying phenotypic domains and test for measurement invariance across adaptive functioning, age, gender and ASD/ADHD clinical diagnoses.

METHODS

Participants included children and youth (aged 3-20 years) with a clinical diagnosis of ASD (n = 727) or ADHD (n = 770) for a total of 1,497 participants. Parents of these children completed the Social Communication Questionnaire (SCQ), a measure of autism symptoms, and the Strengths and Weaknesses of ADHD and Normal Behaviour (SWAN) questionnaire, a measure of ADHD symptoms. An exploratory factor analysis (EFA) was performed on combined SCQ and SWAN items. This was followed by a confirmatory factor analysis (CFA) and tests of measurement invariance.

RESULTS

EFA revealed a four-factor solution (inattention, hyperactivity/impulsivity, social-communication, and restricted, repetitive, behaviours and interests (RRBI)) and a CFA confirmed good model fit. This solution also showed good model fit across subgroups of interest.

CONCLUSIONS

Our study shows that a combined ASD-ADHD phenotype is characterized by two latent ASD domains (social communication and RRBIs) and two latent ADHD domains (inattention and hyperactivity/impulsivity). We established measurement invariance of the derived measurement model across adaptive functioning, age, gender and ASD/ADHD diagnoses.

Awake brain surgery for autistic patients: Is it possible?

Background:

Awake neurosurgery is currently the mainstay for eloquent brain lesions. Opting for an awake operation is affected by a number of patient-related factors. We present a case of a patient with autistic spectrum disorder (ASD) that was successfully operated for a brain tumor through awake craniotomy. To the best of our knowledge, this is the first reported case in the literature.

Case Description:

A 42-year-old patient, with known ASD since his childhood, underwent awake craniotomy for a left supplementary motor area tumor. Detailed preoperative preparation of the patient was done to identify special requirements and establish a good patient-team relationship. Intraoperatively, continuous language and motor testing were performed. Conversation and music were the main distractors used. Throughout the operation, the patient remained calm and cooperative, even during a focal seizure. Mapping allowed for >80% resection of the tumor. Postoperatively, the patient recovered without any deficits.

Conclusion:

This case shows that with growing experience and meticulous preparation, the limits of awake craniotomy can be expanded to include more patients that were previously considered unfit.

Associations between co-occurring conditions and age of autism diagnosis: Implications for mental health training and adult autism research

Adult autism studies are increasingly comprised of later-diagnosed adults, yet little is known about how these adults compare to those diagnosed earlier in life. The present study examines medical and psychiatric conditions endorsed by autistic adults and documents differences between those diagnosed with ASD in childhood versus adulthood, as well as across age groups and sex at birth. 4657 legally independent adults (ages 18-85, M = 33.4 years) with professional ASD diagnoses who completed a medical questionnaire were drawn from the Simons Powering Autism Research Knowledge (SPARK) study. Chi square analyses, t-tests, and logistic regressions were used to compare medical and psychiatric conditions between age groups, sex at birth and adults diagnosed in childhood (before age 21) versus adulthood (at or after 21 years). Overall number of conditions endorsed as being diagnosed by a professional was high, with an average of 1.69 (SD = 2.01) medical or developmental and 2.98 (SD = 2.29) psychiatric conditions reported across the sample. Females were more likely to endorse psychiatric conditions (OR = 1.68). Adult-diagnosed adults were more likely to endorse psychiatric conditions (OR = 2.71) and reported more lifetime psychiatric diagnoses (M = 3.15, SD = 2.23) than their childhood-diagnosed counterparts (M = 2.81, SD = 2.33). These findings underscore the need for research to better understand and treat co-occurring psychiatric conditions in autistic adults and report and consider the age of diagnosis in adult autism samples. Moreover, results suggest it is imperative that mental health professionals receive autism training to promote accurate differential diagnosis and equitable access to mental health care for autistic adults with co-occurring psychiatric conditions.

Can the "female protective effect" liability threshold model explain sex differences in autism spectrum disorder?

Male sex is a strong risk factor for autism spectrum disorder (ASD). The leading theory for a "female protective effect" (FPE) envisions males and females have "differing thresholds" under a "liability threshold model" (DT-LTM). Specifically, this model posits that females require either a greater number or larger magnitude of risk factors (i.e., greater liability) to manifest ASD, which is supported by the finding that a greater proportion of females with ASD have highly penetrant genetic mutations. Herein, we derive testable hypotheses from the DT-LTM for ASD, investigating heritability, familial recurrence, correlation between ASD penetrance and sex ratio, population traits, clinical features, the stability of the sex ratio across diagnostic changes, and highlight other key prerequisites. Our findings reveal that several key predictions of the DT-LTM are not supported by current data, requiring us to establish a different conceptual framework for evaluating alternate models that explain sex differences in ASD.

Repetitive Behavior Scale for Early Childhood (RBS-EC): Psychometrics and Developmental Effects with a Community Sample

Restricted, repetitive behaviors and interests (RRBIs) occur commonly in young children in the course of typical development, but too frequent or persistent RRBIs have been linked to a variety of psychosocial and neurodevelopmental disorders. Unfortunately, a lack of psychometrically sound, feasible instruments stymies RRBI study and intervention in early childhood. Therefore, this study validated an extant RRBI measure (i.e., Repetitive Behavior Scale for Early Childhood; RBS-EC) for predominately neurotypical community children ages 2-7 years via an MTurk survey of 300 caregivers. Confirmatory factor analyses best supported a 4-factor model for the RBS-EC (i.e., repetitive motor, rituals and routines, restricted interests, self-directed behaviors). RBS-EC scores varied significantly with age and gender; namely, RRBIs were typically (1) less frequent but more problematic with older versus younger children and (2) more frequent and problematic with boys versus girls. Findings extend the RBS-EC's utility in RRBI assessment and treatment during early childhood.

Wechsler Intelligence Scale for Adults - Fourth Edition profiles of adults with autism spectrum disorder

AIM

In this study, we have compared 229 Wechsler Adults Intelligence Scale - Fourth Edition (WAIS-IV) cognitive profiles of different severity adults with autism spectrum disorder to verify the impact of several variables including sex, age, level of education and autism severity level in an Italian sample. Moreover, we wanted to find out the optimal cut points for the major intelligence quotients in order to discriminate autism severity levels.

METHODS

Participants were recruited from two National Health System Center in two different Italian regions and were assessed with gold-standard instruments as a part of their clinical evaluation. According to DSM-5, cognitive domains were also measured with multi-componential tests. We used the Italian adaptation of WAIS-IV. We checked our hypotheses using linear regression models and receiver operating characteristics (ROC) curves.

RESULTS

Our results showed that age and level of education have a strong impact on Verbal Comprehension (VCI) and Working Memory Indexes (WMI). Gender differences are relevant when considering the VCI and Processing Speed index (PSI) in which women obtained the best performance. These differences are still relevant when considering cut points of ROC because 69 resulted to be the optimal cut point for women, 65 for men.

CONCLUSIONS

Few conclusions can be assumed only examining Full Scale Intelligence Quotient (FSIQ) scores as it includes many different information about broader cognitive abilities. Looking deeper at main indexes and their subtests findings are consistent with previous research on the disorder (moderate correlations of FSIQ, Perceptual Reasoning index, WMI and PSI with the participants' age), while other results are unforeseen (no effect of sex found on FSIQ score) or novel (significant effect of education on VCI and WMI). Using an algorithm predicting optimal cut point for discriminating through autism severity levels can help clinicians to better label and quantify the required help a person may need, a test cannot replace diagnostic and clinical evaluation by experienced clinicians.

Clinical and demographic differences by sex in autistic Venezuelan children: A cross-sectional study

BACKGROUND

Sex differences in symptom severity and adaptive function in children with ASD have been historically inconsistent and studies are predominantly from American- and European-residing populations. Alike, there is limited information on the complex interplay between sex, intelligence, adaptive function, and autism symptom severity; this is crucial to identify given their predictive value for health outcomes in autism AIM: This study aimed to identify sex differences in autism symptom severity and adaptive function in a sample of Venezuelan children.

METHOD

One-hundred-and-three Venezuelan children ages 3-7 completed a comprehensive assessment for symptom severity, adaptive functioning, and intelligence.

RESULTS

Sex differences were not present in any autism diagnostic domain or adaptive function.Symptom severity was not a significant predictor for adaptive function, which contrasts with studies sampling American children.

CONCLUSION

This study corroborates other findings based on non-American children, where symptom severity was not a function of adaptive function. Awareness of the interplay of culture, sex-related standards, and autism symptomatology will result in better identification and diagnosis of autism regardless of sex or cultural background. What this paper adds? This paper aids the current literature on sex difference on both autism symptom severity and adaptive function. It also provides a snapshot of the relationship between symptom severity, adaptive function, and other psychological variables that influence the outcome of children with ASD.

Developmental Variability in Autism Across 17 000 Autistic Individuals and 4000 Siblings Without an Autism Diagnosis: Comparisons by Cohort, Intellectual Disability, Genetic Etiology, and Age at Diagnosis

Importance

Presence of developmental delays in autism is well established, yet few studies have characterized variability in developmental milestone attainment in this population.

Objective

To characterize variability in the age at which autistic individuals attain key developmental milestones based on co-occurring intellectual disability (ID), presence of a rare disruptive genetic variant associated with neurodevelopmental disorders (NDD), age at autism diagnosis, and research cohort membership.

Design

The study team harmonized data from 4 cross-sectional autism cohorts: the Autism Genetics Research Exchange (n = 3284; 1997-2015), The Autism Simplex Collection (n = 694; 2008-2011), the Simons Simplex Collection (n = 2753; 2008-2011), and the Simons Foundation Powering Autism Research for Knowledge (n = 10 367; 2016-present). The last sample further included 4145 siblings without an autism diagnosis or ID.

Participants

Convenience sample of 21 243 autistic individuals or their siblings without an autism diagnosis aged 4 to 17 years.

Main Outcomes and Measures

Parents reported ages at which participants attained key milestones including smiling, sitting upright, crawling, walking, spoon-feeding self, speaking words, speaking phrases, and acquiring bladder and bowel control. A total of 5295 autistic individuals, and their biological parents, were genetically characterized to identify de novo variants in NDD-associated genes. The study team conducted time-to-event analyses to estimate and compare percentiles in time with milestone attainment across autistic individuals, subgroups of autistic individuals, and the sibling sample.

Results

Seventeen thousand ninety-eight autistic individuals (mean age, 9.15 years; 80.8% male) compared with 4145 siblings without autism or ID (mean age, 10.2 years; 50.2% female) showed delays in milestone attainment, with median (IQR) delays ranging from 0.7 (0.3-1.6) to 19.7 (11.4-32.2) months. More severe and more variable delays in autism were associated with the presence of co-occurring ID, carrying an NDD-associated rare genetic variant, and being diagnosed with autism by age 5 years. More severe and more variable delays were also associated with membership in earlier study cohorts, consistent with autism's diagnostic and ascertainment expansion over the last 30 years.

Conclusions and Relevance

As the largest summary to date of developmental milestone attainment in autism, to our knowledge, this study demonstrates substantial developmental variability across different conditions and provides important context for understanding the phenotypic and etiological heterogeneity of autism.

Impact of Belgian COVID-19 lockdown restrictions on autistic individuals’ socio-communicative behaviors and their parents’ quality of life

Background

In the spring of 2020, Belgian authorities enforced a full lockdown period to contain the spread of the SARS-CoV-2 virus. This lockdown drastically disrupted the daily life of autistic individuals’ and that of their families. In the midst of these extraordinary circumstances, we assessed the impact of social restrictions on autistic individuals’ behavior and their parents’ or caregivers’ quality of life; we also sought to identify individual characteristics that may influence such changes.

Methods

We designed an online survey targeting caregivers living with an autistic child or adult. The questionnaire included 125 five-point Likert questions which targeted changes in families’ quality of life and in autistic individuals’ behavior, as well as factors likely to influence the extent and direction of these changes.

Results

We collected data from 209 French-speaking Belgian respondents. Respondents reported that the lockdown brought about a higher frequency of nonfunctional socio-communicative behaviors, as well as a decrease in families’ quality of life. Parents who had less access to respite care experienced a steeper decrease in their quality of life. Autistic individuals with comorbidities, and whose parents had less access to respite care and implemented fewer rules at home during lockdown were more likely to display nonfunctional socio-communicative behaviors.

Conclusion

COVID-19 lockdown restrictions had a negative impact on both autistic individuals and their parents.

Memantine for autism spectrum disorder

BACKGROUND

Autism spectrum disorder (ASD; also known as autism) is a developmental disability that begins in childhood and is typically seen in around 1% to 2% of children. It is characterised by social communication difficulties and repetitive and restricted behaviours and routines that can have a negative impact on a child's quality of life, achievement at school, and social interactions with others. It has been hypothesised that memantine, which is traditionally used to treat dementia, may be effective in reducing the core symptoms of autism as well as some co-occurring symptoms such as hyperactivity and language difficulties. If memantine is being used to treat the core symptoms of autism, it is important to review the evidence of its effectiveness.

OBJECTIVES

To assess the effects of memantine on the core symptoms of autism, including, but not limited to, social communication and stereotypical behaviours.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, nine other databases and three trials registers up to February 2022. We also checked reference lists of key studies and checked with experts in the field for any additional papers. We searched for retractions of the included studies in MEDLINE, Embase, and the Retraction Watch Database. No retractions or corrections were found.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of any dose of memantine compared with placebo in autistic people. We also included RCTs in which only one group received memantine, but both groups received the same additional therapy (e.g. a behaviour intervention).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were core autism symptoms and adverse effects. Secondary outcomes were language, intelligence, memory, adaptive behaviour, hyperactivity, and irritability. We used GRADE to assess certainty of evidence.

MAIN RESULTS

We included three RCTs (two double-blind and one single-blind) with 204 participants that examined the short-term effect (immediately postintervention) of memantine in autistic people. Two studies took place in the USA and the other in Iran. All three studies focused on children and adolescents, with a mean age of 9.40 (standard deviation (SD) 2.26) years. Most participants were male (range across studies 73% to 87%). The diagnosis of ASD was based on the Diagnostic and Statistical Manual of Mental Disorders (4th edition; 4th edition, text revision; or 5th edition). To confirm the diagnosis, one study used the Autism Diagnostic Observation Schedule (ADOS) and the Autism Diagnostic Interview-Revised (ADI-R); one used ADOS, ADI-R or the Autism Diagnostic Interview Screener; and one used the Gilliam Autism Rating Scale. Dosage of memantine was based on the child's weight and ranged from 3 mg to 15 mg per day.  Comparisons  Two studies examined memantine compared with placebo; in the other study, both groups had a behavioural intervention while only one group was given memantine.  Risk of bias All studies were rated at high risk of bias overall, as they were at high or unclear risk of bias across all but four domains in one study, and all but two domains in the other two studies. One study was funded by Forest Laboratories, LLC, (Jersey City, New Jersey), Allergan. The study sponsor was involved in the study design, data collection (via contracted clinical investigator sites), analysis and interpretation of data, and the decision to present these results. The other two studies reported no financial support or sponsorship; though in one of the two, the study medication was an in-kind contribution from Forest Pharmaceuticals. Primary outcomes There was no clear evidence of a difference between memantine and placebo with respect to severity of core symptoms of autism, although we are very uncertain about the evidence. The standardised mean difference in autism symptoms score in the intervention group versus the control group was -0.74 standard deviations (95% confidence interval (CI) -2.07 to 0.58; 2 studies, 181 participants; very low-certainty evidence; medium effect size); lower scores indicate less severe autistic symptoms. Two studies (144 participants) recorded adverse effects that the authors deemed related to the study and found there may be no difference between memantine and placebo (odds ratio (OR) 0.64, 95% CI 0.17 to 2.39; low-certainty evidence). Secondary outcomes There may be no difference between memantine and placebo on language (2 studies, 144 participants; low-certainty evidence); memory or adaptive behaviour (1 study, 23 participants; both low-certainty evidence); or hyperactivity or irritability (1 study, 121 participants; both low-certainty evidence).

AUTHORS' CONCLUSIONS

It is unclear whether memantine is an effective treatment for autistic children. None of the three included trials reported on the effectiveness of memantine in adults. Further studies using rigorous designs, larger samples, longer follow-up and clinically meaningful outcome measures that are important to autistic people and their families will strengthen our knowledge of the effects of memantine in autism.

Measuring autism in males and females with a differential item functioning approach: Results from a nation-wide population-based study

Existing screening instruments for Autism Spectrum Disorder (ASD) might be prone to detect a male manifestation of ASD. Here, we examined the 17 items from the ASD domain in the Autism-Tics, ADHD and other Comorbidities inventory (A-TAC) for Differential Item Functioning (DIF). Data were obtained from the Child and Adolescent Twin Study in Sweden (CATSS) in which parents have responded to the A-TAC. Information regarding a registered diagnosis of ASD were retrieved from the National Patient Register. The cohort was divided into a developmental sample for evaluation of DIF, and a validation sample for examination of the diagnostic accuracy of the total ASD domain, and a novel male and female short form. Our main finding included the identification of DIF for six items, three favouring males and three favouring females. The full, 17 item, ASD domain and the male and female short form showed excellent ability to capture ASD diagnoses in both males and females up to the age of nine years. The full ASD domain in A-TAC is psychometrically largely equivalent across sex and the limited differences between males and females diminish the need for a sex-specific scoring when utilizing the 17 item total score.

The Early Childhood Signs of Autism in Females: a Systematic Review

Compared to males, females are at a much greater likelihood of receiving a later diagnosis of autism, which impacts their opportunity to receive early support. To assist with early identification, this systematic literature review aimed to ascertain whether females differ from males in the early childhood signs of autism. The small number of heterogeneous studies made it difficult to draw conclusions, although it appears that females and males under 6 years of age are more similar than different in terms of their expression of autistic behaviours. Given the discrepant sex/gender ratio in autism, these findings highlight the importance of exploring whether there are different and/or specific, not yet identified, early signs of autism in females and males.

Verbal entrainment in autism spectrum disorder and first-degree relatives

Entrainment, the unconscious process leading to coordination between communication partners, is an important dynamic human behavior that helps us connect with one another. Difficulty developing and sustaining social connections is a hallmark of autism spectrum disorder (ASD). Subtle differences in social behaviors have also been noted in first-degree relatives of autistic individuals and may express underlying genetic liability to ASD. In-depth examination of verbal entrainment was conducted to examine disruptions to entrainment as a contributing factor to the language phenotype in ASD. Results revealed distinct patterns of prosodic and lexical entrainment in individuals with ASD. Notably, subtler entrainment differences in prosodic and syntactic entrainment were identified in parents of autistic individuals. Findings point towards entrainment, particularly prosodic entrainment, as a key process linked to social communication difficulties in ASD and reflective of genetic liability to ASD.

Sex Differences in Autism Spectrum Disorder: Diagnostic, Neurobiological, and Behavioral Features

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder with a worldwide prevalence of about 1%, characterized by impairments in social interaction, communication, repetitive patterns of behaviors, and can be associated with hyper- or hypo-reactivity of sensory stimulation and cognitive disability. ASD comorbid features include internalizing and externalizing symptoms such as anxiety, depression, hyperactivity, and attention problems. The precise etiology of ASD is still unknown and it is undoubted that the disorder is linked to some extent to both genetic and environmental factors. It is also well-documented and known that one of the most striking and consistent finding in ASD is the higher prevalence in males compared to females, with around 70% of ASD cases described being males. The present review looked into the most significant studies that attempted to investigate differences in ASD males and females thus trying to shade some light on the peculiar characteristics of this prevalence in terms of diagnosis, imaging, major autistic-like behavior and sex-dependent uniqueness. The study also discussed sex differences found in animal models of ASD, to provide a possible explanation of the neurological mechanisms underpinning the different presentation of autistic symptoms in males and females.

Putative complement control protein CSMD3 dysfunction impairs synaptogenesis and induces neurodevelopmental disorders

Recent studies have reported that complement-related proteins modulate brain development through regulating synapse processes in the cortex. CSMD3 belongs to a group of putative complement control proteins. However, its role in the central nervous system and synaptogenesis remains largely unknown. Here we report that CSMD3 deleterious mutations occur frequently in patients with neurodevelopmental disorders (NDDs). Csmd3 is predominantly expressed in cortical neurons of the developing cortex. In mice, Csmd3 disruption induced retarded development and NDD-related behaviors. Csmd3 deficiency impaired synaptogenesis and neurogenesis, allowing fewer neurons reaching the cortical plate. Csmd3 deficiency also induced perturbed functional networks in the developing cortex, involving a number of downregulated synapse-associated genes that influence early synaptic organization and upregulated genes related to immune activity. Our study provides mechanistic insights into the endogenous regulation of complement-related proteins in synaptic development and supports the pathological role of CSMD3 in NDDs.

Analysis of a Repetitive Language Coding System: Comparisons between Fragile X Syndrome, Autism, and Down Syndrome

Expressive language sampling (ELS) is a frequently used tool for language analysis, as it can be used across widely ranging cognitive and language abilities. ELS can also evaluate pragmatic language, including excessive self-repetition, which is challenging to assess with traditional standardized assessments. This study explored how a well-established ELS protocol can assess three types of linguistic self-repetition in three neurodevelopmental disabilities: fragile X syndrome (FXS), autism spectrum disorder (ASD), and Down syndrome (DS). We examined its ability to differentiate between these disorders, the relationships between repetitive language and other participant characteristics, and initial construct validity. We found that the groups with FXS and ASD differed significantly on each of the three repetitive language measure, and that the group with DS differed from either ASD or FXS on two. Cognitive ability was significantly related to phrase repetition in the group with ASD. When the groups were combined, there was evidence of convergent and divergent validity. This study extends previous research on ELS and supports its use as a means to characterize pragmatic language. It also provides information about the relationships between repetitive language and other phenotypic characteristics.

Sex Differences in Spatial Learning and Memory in Valproic Acid Rat Model of Autism: Possible Beneficial Role of Exercise Interventions

In the current study, we first tried to determine sex differences in spatial learning and memory in the valproic acid (VPA) rat model of autism. Second, the effects of interval training (IT) and continuous training (CT) exercises were examined in male and female offsprings. To induce autism-like animal model, the pregnant rats were injected 500 mg/kg NaVPA (intraperitoneal) at the embryonic day 12.5. IT and CT aerobic exercises were started at postnatal day 56. Then, on postnatal days 84–89, a Morris water maze (MWM) test was conducted on the separate groups of offsprings. Aerobic training was performed on a rodent treadmill with 0% slope for 8 weeks, 5 days/week, and 50 min/day. Unlike control animals, VPA-exposed female offspring had a better performance than VPA-exposed male offspring in MWM acquisition. In the case of MWM reference memory, we did not observe a sex difference between VPA-exposed male and VPA-exposed female offspring. Both IT and CT exercises in both control and VPA-exposed male rats significantly improved MWM acquisition. Moreover, both IT and CT exercises significantly improved MWM acquisition in control female rats. In addition, IT exercise (but not CT) significantly improved MWM acquisition in VPA-exposed female offsprings. Both IT and CT exercises in VPA-exposed that male and female offsprings improved the MWM reference memory. In conclusion, our observation demonstrated that prenatal exposure to VPA affects the spatial learning and memory in a sex dependent manner. We have shown that both IT and CT exercises are able to improve cognitive function in healthy and autistic rat offsprings.

Sex- and age-related differences in autistic behaviours in children with neurofibromatosis type 1

This study investigated sex and age differences in autistic behaviours in children with neurofibromatosis type 1 (NF1) who scored within the clinical range on the Social Responsiveness Scale - Second Edition (T score ≥ 60). Thirty-four males and 28 females (3-16 years) were assessed with the Autism Diagnostic Observation Schedule - Second Edition and Autism Diagnostic Interview - Revised. Across both measures, males exhibited greater social communication deficits relative to females. Age-related abatement of social communication difficulties was observed for males but not females. Conversely, no sex differences were found for restricted/repetitive behaviours, which were stable over time for both males and females. The findings are discussed within the context of broader neurodevelopmental considerations that are common in NF1.

rs-fMRI and machine learning for ASD diagnosis: a systematic review and meta-analysis

Autism Spectrum Disorder (ASD) diagnosis is still based on behavioral criteria through a lengthy and time-consuming process. Much effort is being made to identify brain imaging biomarkers and develop tools that could facilitate its diagnosis. In particular, using Machine Learning classifiers based on resting-state fMRI (rs-fMRI) data is promising, but there is an ongoing need for further research on their accuracy and reliability. Therefore, we conducted a systematic review and meta-analysis to summarize the available evidence in the literature so far. A bivariate random-effects meta-analytic model was implemented to investigate the sensitivity and specificity across the 55 studies that offered sufficient information for quantitative analysis. Our results indicated overall summary sensitivity and specificity estimates of 73.8% and 74.8%, respectively. SVM stood out as the most used classifier, presenting summary estimates above 76%. Studies with bigger samples tended to obtain worse accuracies, except in the subgroup analysis for ANN classifiers. The use of other brain imaging or phenotypic data to complement rs-fMRI information seems promising, achieving higher sensitivities when compared to rs-fMRI data alone (84.7% versus 72.8%). Finally, our analysis showed AUC values between acceptable and excellent. Still, given the many limitations indicated in our study, further well-designed studies are warranted to extend the potential use of those classification algorithms to clinical settings.

Understanding strengths and challenges of people with autism: insights from parents and practitioners

This study is an attempt to bridge the gap between the understanding of strengths and challenges of people with autism to operationalize a strength-based approach to serve people with autism effectively. By virtue of being based on firsthand accounts by parents and practitioners the people who spend prolonged periods with people with autism in natural settings, and are privy to direct observation of abilities and challenges, the study yields in-depth information that addresses a continued gap in the existing literature on the subject. Twenty participants (13 parents and seven practitioners) took part in the study through a semi-structured questionnaire and face-to-face interviews. Data were analyzed following qualitative thematic analysis methodology. Strengths and related challenges experienced were extracted as the broad themes, based on which support needs were derived and future directions recommended. The paper recommends strategic home-school collaborations with crucial, concurrent roles played by parents and practitioners.

Atypical sensory processing features in children with autism, and their relationships with maladaptive behaviors and caregiver strain

Atypical sensory processing occurs in up to 97% of children on the autism spectrum. Children who are on the autism spectrum also commonly demonstrate challenging behaviors, and their caregivers report increased levels of strain in daily life. The aim of this study was to explore four sensory processing features; seeking, avoiding, sensitivity, and registration, and their relationships with maladaptive behaviors in children with autism, as well as with caregiver strain. Participants comprised 75 children with autism aged 7–12 years (M = 7.81). Caregivers completed three questionnaire measures examining child sensory processing, maladaptive behaviors, and perceptions of caregiver strain. We found avoiding significantly associated with irritability. Avoiding also displayed the strongest relationship with global caregiver strain. Avoiding and seeking were strongly related to hyperactivity/noncompliance (components of maladaptive behavior). A multiple regression was performed to explore how atypical sensory processing features and maladaptive behaviors together predicted caregiver strain. Together, maladaptive behaviors and sensory features accounted for 58% of the variance in total caregiver strain. The only significant individual predictor of total caregiver strain was sensory avoiding, which uniquely accounted for 5.76% of the variation. The findings suggest that atypical sensory processing is associated with overall caregiver strain, above that explained by maladaptive behaviors. Implications for targeted support for the benefit of the child, parents and family unit are discussed.

Behavioral gender differences across Pre-School Children with Autism Spectrum Disorders: a cross-sectional study

There is increasing literature showing that the presentation of Autism Spectrum Disorder (ASD) could be different according to the sex of the patient. Through the analysis of the Autism Diagnostic Interview Revised interview results of a study group consisting of 56 preschool children diagnosed with ASD potential differences in the presentation of ASD were searched. Variables investigated were verbal abilities, the presence/absence of unusual sensory interests, as well as of echolalia. The results showed significant differences between gender in restricted and repetitive behavior (p < 0.01), in particular for those children who have no unusual sensory interest (p < 0.05) and with minimal verbal ability (p < 0.05). The findings contribute providing evidences on phenotypical differences in preschool children with a diagnosis of Autism Spectrum Disorder.

Phenotypic differences between female and male individuals with suspicion of autism spectrum disorder

Background

Although autism spectrum disorder (ASD) is a common developmental disorder, our knowledge about a behavioral and neurobiological female phenotype is still scarce. As the conceptualization and understanding of ASD are mainly based on the investigation of male individuals, females with ASD may not be adequately identified by routine clinical diagnostics. The present machine learning approach aimed to identify diagnostic information from the Autism Diagnostic Observation Schedule (ADOS) that discriminates best between ASD and non-ASD in females and males.

Methods

Random forests (RF) were used to discover patterns of symptoms in diagnostic data from the ADOS (modules 3 and 4) in 1057 participants with ASD (18.1% female) and 1230 participants with non-ASD (17.9% % female). Predictive performances of reduced feature models were explored and compared between females and males without intellectual disabilities.

Results

Reduced feature models relied on considerably fewer features from the ADOS in females compared to males, while still yielding similar classification performance (e.g., sensitivity, specificity).

Limitations

As in previous studies, the current sample of females with ASD is smaller than the male sample and thus, females may still be underrepresented, limiting the statistical power to detect small to moderate effects.

Conclusion

Our results do not suggest the need for new or altered diagnostic algorithms for females with ASD. Although we identified some phenotypic differences between females and males, the existing diagnostic tools seem to sufficiently capture the core autistic features in both groups.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13229-022-00491-9.

Global prevalence of autism: A systematic review update

Prevalence estimates of autism are essential for informing public policy, raising awareness, and developing research priorities. Using a systematic review, we synthesized estimates of the prevalence of autism worldwide. We examined factors accounting for variability in estimates and critically reviewed evidence relevant for hypotheses about biological or social determinants (viz., biological sex, sociodemographic status, ethnicity/race, and nativity) potentially modifying prevalence estimates of autism. We performed the search in November 2021 within Medline for studies estimating autism prevalence, published since our last systematic review in 2012. Data were extracted by two independent researchers. Since 2012, 99 estimates from 71 studies were published indicating a global autism prevalence that ranges within and across regions, with a median prevalence of 100/10,000 (range: 1.09/10,000 to 436.0/10,000). The median male‐to‐female ratio was 4.2. The median percentage of autism cases with co‐occurring intellectual disability was 33.0%. Estimates varied, likely reflecting complex and dynamic interactions between patterns of community awareness, service capacity, help seeking, and sociodemographic factors. A limitation of this review is that synthesizing methodological features precludes a quality appraisal of studies. Our findings reveal an increase in measured autism prevalence globally, reflecting the combined effects of multiple factors including the increase in community awareness and public health response globally, progress in case identification and definition, and an increase in community capacity. Hypotheses linking factors that increase the likelihood of developing autism with variations in prevalence will require research with large, representative samples and comparable autism diagnostic criteria and case‐finding methods in diverse world regions over time.

Modestly increasing systemic interleukin-6 perinatally disturbs secondary germinal zone neurogenesis and gliogenesis and produces sociability deficits

Epidemiologic studies have demonstrated that infections during pregnancy increase the risk of offspring developing Schizophrenia, Autism, Depression and Bipolar Disorder and have implicated interleukin-6 (IL-6) as a causal agent. However, other cytokines have been associated with the developmental origins of psychiatric disorders; therefore, it remains to be established whether elevating IL-6 is sufficient to alter the trajectory of neural development. Furthermore, most rodent studies have manipulated the maternal immune system at mid-gestation, which affects the stem cells and progenitors in both the primary and secondary germinal matrices. Therefore, a question that remains to be addressed is whether elevating IL-6 when the secondary germinal matrices are most active will affect brain development. Here, we have increased IL-6 from postnatal days 3-6 when the secondary germinal matrices are rapidly expanding. Using Nestin-Cre^ERT2 fate mapping we show that this transient increase in IL-6 decreased neurogenesis in the dentate gyrus of the dorsal hippocampus, reduced astrogliogenesis in the amygdala and decreased oligodendrogenesis in the body and splenium of the corpus callosum all by ∼ 50%. Moreover, the IL-6 treatment elicited behavioral changes classically associated with neurodevelopmental disorders. As adults, IL-6 injected male mice lost social preference in the social approach test, spent ∼ 30% less time socially engaging with sexually receptive females and produced ∼ 50% fewer ultrasonic vocalizations during mating. They also engaged ∼ 50% more time in self-grooming behavior and had an increase in inhibitory avoidance. Altogether, these data provide new insights into the biological mechanisms linking perinatal immune activation to complex neurodevelopmental brain disorders.

Exploring Growth in Expressive Communication of Infants and Toddlers With Autism Spectrum Disorder

One of the earliest indicators of autism spectrum disorder (ASD) is delay in language and social communication. Despite consensus on the benefits of earlier diagnosis and intervention, our understanding of the language growth of children with ASD during the first years of life remains limited. Therefore, this study compared communication growth patterns of infants and toddlers with ASD to growth benchmarks of a standardized language assessment. We conducted a retrospective analysis of growth on the Early Communication Indicator (ECI) of 23 infants and toddlers who received an ASD diagnosis in the future. At 42 months of age, children with ASD had significantly lower rates of gestures, single words, and multiple words, but significantly higher rates of nonword vocalizations. Children with ASD had significantly slower growth of single and multiple words, but their rate of vocalization growth was significantly greater than benchmark. Although more research is needed with larger samples, because the ECI was designed for practitioners to monitor children's response to intervention over time, these findings show promise for the ECI's use as a progress monitoring measure for young children with ASD. Limitations and the need for future research are discussed.

Sex differences in childhood sleep and health implications

CONTEXT

Sleep is critical for optimal childhood metabolic health and neurodevelopment. However, there is limited knowledge regarding childhood sex differences in sleep, including children with neurodevelopmental disorders, and the impact of such differences on metabolic health.

OBJECTIVE

To evaluate if sex differences in childhood sleep exist and if sleep associates with metabolic health outcomes equally by sex. Using autism spectrum disorder (ASD) as a case study, we also examine sleep sex differences in children with a neurodevelopmental disorder.

METHODS

A narrative review explored the literature focussing on sex differences in childhood sleep.

RESULTS

Sex differences in sleep were not detected among pre-adolescents. However, female adolescents were more likely to report impaired sleep than males. Childhood obesity is more common in males. Shorter sleep duration may be associated with obesity in male pre-adolescents/adolescents; although findings are mixed. ASD is male-predominant; yet, there was an indication that pre-adolescent female children with ASD had more impaired sleep.

CONCLUSION

Sex differences in sleep appear to emerge in adolescence with more impaired sleep in females. This trend was also observed among pre-adolescent female children with ASD. Further research is needed on sex differences in childhood sleep and metabolic health and the underlying mechanisms driving these differences.

Sex/gender differences in children with autism spectrum disorder: A brief overview on epidemiology, symptom profile, and neuroanatomy

Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental conditions whose shared core features are impairments in social interaction and communication as well as restricted patterns of behavior, interests, and activities. The significant and consistent male preponderance in ASD prevalence has historically affected the scientific knowledge of autism in females as regards, inter alia, the clinical presentation, the genetic architecture, and the structural brain underpinnings. Indeed, females with ASD are under-investigated as samples recruited for clinical research typically reflect the strong male bias of the disorder. In the last years, the study of the various aspects of sex/gender (s/g) differences in ASD is gaining increased clinical and research interest resulting in a growing number of investigations on this topic. Here, I review and discuss evidence emerged from epidemiological, clinical, and neuroimaging studies in the last decade focusing on s/g differences in children with ASD. These studies are the prerequisites for the development of assessment and treatment practices which take into consideration s/g differences in ASD. Ultimately, a better understanding of s/g differences aims at improving healthcare for both ASD males and females.

Missed diagnoses and misdiagnoses of adults with autism spectrum disorder

Autism spectrum disorder (ASD) is a group of life-long neurodevelopmental disorders affecting 1.5% of the general population. The present study aimed to evaluate the psychiatric history of a group of adults who received the first diagnosis of ASD in two Italian university centers. Diagnoses of ASD were confirmed by a team of psychiatrists with wide expertise in the field, after the administration of standardized tools (i.e., ADOS-2, ADI-R). The sample comprised 161 participants, of which 114 (79.5%) were males. The median age of diagnosis was 23 years (range 18-55), with a median IQ of 100 (range 30-145). The first evaluation by a mental health professional was performed at a median age of 13 years, with a gap of 11 years between the first evaluation and the diagnosis of ASD. 33.5% of participants had never received a psychiatric diagnosis, while the rest of the sample had received one or more diagnoses different from ASD. The most common past diagnoses were intellectual disability, psychoses, personality disorders, and depression. Sex differences were detected in the age of diagnosis and ADOS-2 scores. Our results provide important information for both child and adult psychiatrists. Given the prevalence of autism and the high rates of co-occurrent psychiatric conditions, it is important for clinicians to consider ASD in the differential diagnostic process.

Assessment of theory of mind in Tunisian verbal children with autism spectrum disorder

The present study examined performance in Theory of Mind (ToM) in a group of 31 Arabic-speaking verbal children (7-12 years-old) with autism spectrum disorder (ASD), in comparison with neurotypical controls (NT) matched for age and for cognitive abilities. An innovative task in a digital format named "The Tunisian Social Situations Instrument" (TSSI) was used and allowed us to study four different subdomains of ToM: attribution of intention and epistemic ToM (cognitive ToM), affective ToM, and detection of faux pas (advanced ToM). Our study showed impairments in ToM in children with ASD, similar to those reported in the literature. Our findings additionally suggested that affective and advanced ToM, specifically the detection of faux pas, might be more challenging for ASD children than other components of ToM. Future studies with larger number of children may lead us to specify which subdomains are the most impaired in order to develop specific tools targeting these specific impairments.

Sex differences in age of diagnosis of autism spectrum disorder: Preliminary evidence from Uganda

This study was performed to determine (a) the age at which autism spectrum disorder (ASD) is first diagnosed in Ugandan children receiving mental health services, (b) whether age at diagnosis varies by sex and clinical presentation, and (c) the average age of ASD diagnosis in children manifesting comorbid conditions. A retrospective chart review was performed and demographic as well as clinical data were collected from children with ASD diagnoses who attended two mental health clinics in Uganda between 2014 and 2019. Descriptive statistics such as percentages, means, and standard deviations were used to summarize the data. Independent t-test was also performed to determine differences in the mean age of diagnosis between males and females. Two hundred and thirty-seven (156 males, 81 females) children with ASD were identified. The average age of ASD diagnosis was (6.9 ± 4.0) years. A statistically significant difference in age of ASD diagnosis was found between males and females (t = -2.106, p = 0.036), such that on average females received a diagnosis at least 1 year later than males. Of the 237 participants, 53.6% were identified with ASD only, 16.0% had ASD and ADHD, 10.5% were diagnosed with ASD and epilepsy, and 7.2% had a diagnosis of complex ASD. The results confirm delays in access to ASD diagnosis and suggest that females are more likely to receive a ASD diagnosis later than males within the Ugandan context. ASD awareness should be intensified to improve public or professional knowledge about ASD to enhance early identification in Uganda.

Sex-related differences in clinical characteristics of children with ASD without ID: Results from the ELENA cohort

OBJECTIVE

The literature on sex related-clinical differences for children with autism spectrum disorder (ASD) is highly contradictory, whereas this topic has major clinical implications. We aimed to investigate sex-related clinical differences in children with ASD without intellectual disability (ID).

MATERIALS AND METHODS

We compared 319 boys and 65 girls with ASD without ID, aged from 2 to 12 years, recruited from a multiregional cohort on their clinical profiles based on the scores for the Vineland-II, the SRS-2, the ADOS calibrated severity score, sensory processing, aberrant behaviors, and comorbidity rates.

RESULTS

Our results confirm a high sex ratio of 4.9 males/females. Many similarities were found in the clinical profiles. However, we found that girls had higher SRS-2 total scores. In addition, there was a negative correlation between the SRS-2 total score and the intellectual quotient level (IQ) for girls only.

CONCLUSION

We confirm the higher rates of boys with ASD without ID. A comparison between the girls and boys showed them to have similar clinical profiles, except for the SRS- 2 total scores, which were higher among girls, suggesting more severe social impairment perceived by parents. Our findings that the cognitive level is related to ASD severity in girls should be taken into account during the diagnostic procedure in the clinical interpretation of gold-standard measures of ASD, and additional clinical observations are necessary.

CLINICAL TRIAL REGISTRATION

[ClinicalTrials.gov], identifier [NCT02625116s].

Interpersonal synchrony: Interaction variables and gender differences in preschoolers with ASD

BACKGROUND

Females with ASD tend to be under-recognized as they might present a different symptom manifestation, better social abilities, and masking behaviors. Since the main limitation of current literature on gender differences is represented by focusing on broad constructs, research needs to prioritize narrower constructs related to the subdomains of social abilities. Hence, the aim of this work was to explore gender differences in Interpersonal Synchrony of children with ASD.

METHOD

N = 51 psychologist-child dyads, 25 females and 26 males participated in the study. An Observational Coding Scheme to study interaction features was applied to video-recorded sessions of the ADOS-2 administration.

RESULTS

Females presented more synchronous behaviors with shorter latencies. Their interplays were longer, more complex, more engaging and most frequently adequately concluded with respect to males. The complexity of interchanges, their total duration and the proportion of exchanges adequately terminated correlated with the Social Affect score, Personal-Social, and Language Quotients in females, but not in males. The success rate of psychologist proposals correlated with Language Quotient in both males and females. The number of exchanges positively correlated with the Performance Quotient in males. Despite females being significantly older than males, age-related differences did not emerge.

CONCLUSIONS

Our findings suggest the importance of studying gender differences with respect to interaction variables. Females may present better IS abilities which, in turn, may promote social and language development. Further, our results suggested that successful interactions seem to rely more on social abilities in females, while males appeared to rely more on performance skills.

Neural Transcriptomic Analysis of Sex Differences in Autism Spectrum Disorder: Current Insights and Future Directions

Autism spectrum disorder (ASD) is consistently diagnosed 3 to 5 times more frequently in males than females, a dramatically sex-biased prevalence that suggests the involvement of sex-differential biological factors in modulating risk. The genomic scale of transcriptomic analyses of human brain tissue can provide an unbiased approach for identifying genes and associated functional processes at the intersection of sex-differential and ASD-impacted neurobiology. Several studies characterizing gene expression changes in the ASD brain have been published in recent years with increasing sample size and cellular resolution. These studies report several convergent patterns across data sets and genetically heterogeneous samples in the ASD brain, including elevated expression of gene sets associated with glial and immune function, and reduced expression of gene sets associated with neuronal and synaptic functions. Assessment of neurotypical cortex tissue has reported parallel patterns by sex, with male-elevated expression of overlapping sets of glial/immune-related genes and female-biased expression of neuron-associated genes, suggesting potential roles for these cell types in sex-differential ASD risk mechanisms. However, validating and further exploring these mechanisms is challenged by the available data, as existing studies of ASD brain include a limited number of female ASD donors and focus predominantly on cortex regions not known to show pronounced sex-differential morphology or function. With this review, we summarize convergent findings from several landmark studies of the transcriptome in ASD brain and their relationship to sex-differential gene expression, and we discuss limitations and remaining questions regarding transcriptomic analysis of sex differences in ASD.

The relationship between autism spectrum and sleep-wake traits

Autistic children and adults often have sleep disturbances, which may affect their and their family's quality of life. Yet, the relationship between sleep-wake patterns and autism spectrum traits is understudied. Identifying such relationships could lead to future research elucidating common mechanistic underpinnings. Thus, we aimed to determine whether sleep-wake patterns, specifically related to sleep, physical activity, and the daily sleep-wake rhythm (i.e., circadian rhythm), are associated with autism spectrum-related traits. Accelerometer-derived sleep-wake parameters were estimated in individuals with autistic spectrum traits and their family members (N = 267). We evaluated autism spectrum traits using the Social Responsiveness Scale (SRS) to assess the presence and severity of social impairment and the Behavior Rating Inventory of Executive Function (BRIEF) to assess executive function. The linear multivariate regression analysis (using SOLAR-Eclipse) showed that in adults, increased core autism spectrum traits and executive dysfunction were associated with disruption of several sleep-wake parameters, particularly related to the daily sleep-wake rhythm, and that executive dysfunction was associated with disrupted sleep quality and level of physical activity. We highlight the interplay between daytime function and disrupted sleep-wake patterns, specifically related to the daily sleep-wake rhythm, that could guide future research into common mechanisms.

Psychopathy in women: insights from neuroscience and ways forward for research

Psychopathy is a severe form of personality disturbance, resulting in a detrimental impact on individuals, healthcare systems, and society as a whole. Until relatively recently, most research in psychopathy has focused on male samples, not least because of its link with criminal behavior and the large proportion of violent crime committed by men. However, psychopathy in women also leads to considerable problems at an individual and societal level, including substance misuse, poor treatment outcomes, and contribution to ever-increasing numbers of female prisoners. Despite this, due to relative neglect, most research into adult female psychopathy is underpowered and outdated. We argue that the field needs revitalizing, with a focus on the developmental nature of the condition and neurocognitive research. Recent work international consortia into conduct disorder in female youth-a precursor of psychopathy in female adults-gives cause for optimism. Here, we outline key strategies for enriching research in this important field with contemporary approaches to other psychiatric conditions.

Barriers to Autism Spectrum Disorder Diagnosis for Young Women and Girls: a Systematic Review

There is increased recognition that women and girls with autism spectrum disorders (ASD) are underserved by the clinical criteria and processes required to receive a diagnosis. This mixed-methods systematic review aimed to identify key barriers to obtaining an ASD diagnosis in girls and young women under 21 years. Six themes were identified that focused on perceived gendered symptoms, namely behavioural problems, social and communication abilities, language, relationships, additional diagnoses/difficulties and restricted and repetitive behaviours and interests. Five themes were identified as (parental) perceived barriers to diagnosis, namely compensatory behaviours, parental concerns, others’ perceptions, lack of information/resources and clinician bias. This review highlights the importance of enhancing widespread understanding and recognition of ASD presentation in females across development. PROSPERO Centre for Reviews and Dissemination (ID 2018 CRD42018087235)

Male to female ratios in autism spectrum disorders by age, intellectual disability and attention-deficit/hyperactivity disorder

OBJECTIVE

To examine the gender distribution in ASD in adults compared with children and the impact of comorbid intellectual disability (ID) and attention-deficit/hyperactivity disorder (ADHD) on the male to female ratio (MFR).

METHODS

We estimated the MFR and the male prevalence ratio (PR) for ASD in adults and children using the Medical Birth Registry of Norway, including all individuals born during 1967-2011. We examined variation with age, comorbid ID and ADHD as defined by diagnoses in the Norwegian Patient Registry during 2008-2015 and/or a dispensed prescription for ADHD medication.

RESULTS

The sample included 1,701,206 adults and 804,146 children, including 8,995 (0.5%) adults and 8,056 (1.0%) children with ASD, 53,822 (3.2%) adults and 26,967 (3.4%) children with ADHD and 9,178 (0.5%) adults and 5,038 (0.6%) children with ID. The MFR for ASD was 3.67 in children and 2.57 in adults, corresponding to a male PR in ASD of 1.54 (95% CI 1.53-1.56) and 1.41 (1.39-1.24), respectively. Comorbid ID decreased the MFR and the male PR in both adults and children, whereas comorbid ADHD significantly increased the male PR in children. The MFR and the population prevalence of ASD, ADHD and ID decreased from children to younger adults and yet further to older adults.

CONCLUSION

We found a lower MFR and male PR in adults than in children. Findings suggest the strong male predominance seen in childhood/clinical studies of ASD diminishes in adult samples, possibly reflecting the influence of non-aetiological factors such as later diagnosis in females, diagnostic biases and diagnostic trends.

Biopsychological correlates of repetitive and restricted behaviors in autism spectrum disorders

BACKGROUND

Autism Spectrum Disorder (ASD) is considered a neurodevelopmental condition that is characterized by alterations in social interaction and communication, as well as patterns of restrictive and repetitive behaviors (RRBs). RRBs are defined as broad behaviors that comprise stereotypies, insistence on sameness, and attachment to objects or routines. RRBs can be divided into lower-level behaviors (motor, sensory, and object-manipulation behaviors) and higher-level behaviors (restrictive interests, insistence on sameness, and repetitive language). According to the DSM-5, the grade of severity in ASD partially depends on the frequency of RRBs and their consequences for disrupting the life of patients, affecting their adaptive skills, and increasing the need for parental support.

METHODS

We conducted a systematic review to examine the biopsychological correlates of the symptomatic domains of RRBs according to the type of RRBs (lower- or higher-level). We searched for articles from the National Library of Medicine (PubMed) using the terms: autism spectrum disorders, ASD, and autism-related to executive functions, inhibitory control, inflexibility, cognitive flexibility, hyper or hypo connectivity, and behavioral approaches. For describing the pathophysiological mechanism of ASD, we also included animal models and followed PRISMA guidelines.

RESULTS

One hundred and thirty-one articles were analyzed to explain the etiology, continuance, and clinical evolution of these behaviors observed in ASD patients throughout life.

CONCLUSIONS

Biopsychological correlates involved in the origin of RRBs include alterations in a) neurotransmission system, b) brain volume, c) inadequate levels of growth factors, d) hypo- or hyper-neural connectivity, e) impairments in behavioral inhibition, cognitive flexibility, and monitoring and f) non-stimulating environments. Understanding these lower- and higher-level of RRBs can help professionals to improve or design novel therapeutic strategies.

Missing from the Narrative: A Seven-Decade Scoping Review of the Inclusion of Black Autistic Women and Girls in Autism Research

The intersectional experiences of Black autistic women and girls (BAWG) are missing from medical and educational research on autism spectrum disorder (ASD). Understanding the intersectional experiences of BAWG is important due to the rising prevalence of autism in Black children and girls (Centers for Disease Control and Prevention (CDC), 2020) and the concurrent lack of availability of culturally relevant autism-related interventions (Maenner et al., 2020; West et al., 2016). Intersectionality is the study of the overlapping discrimination produced by systems of oppression (Collins, 2019; Crenshaw, 1989, 1991) and allows the researcher to simultaneously address race and disability in special education (Artiles, 2013). In this scoping review, the authors used the PRISMA-ScR checklist (Tricco et al., 2018) and Arskey and O'Malley's (2005) framework to investigate the degree to which autism-related research (ARR) has included the intersectional experiences of BAWG. Utilizing narrative synthesis, strengths and gaps across the current body of literature are identified in order to set new directions for intersectional ARR. Overall, the authors found that across a 77-year period, three studies foregrounded BAWG and none addressed intersectionality as measured through criteria advanced by García and Ortiz (2013). These results reveal the scholarly neglect BAWG face in ARR, discourse, policy, and practice. A future agenda including research, practice, and policy priorities is identified and discussed.

Sex/Gender Differences in CARS2 and GARS-3 Item Scores: Evidence of Phenotypic Differences Between Males and Females with ASD

Growing evidence suggests that autistic females are more likely to be diagnostically overlooked than males, perhaps due to differences in ASD presentations (van Wijngaarden-Cremers in JAMA 44:627-635, 2014). To investigate specific behaviours in which differences lie, we analysed profiles of 777 children using the Childhood Autism Rating Scale (Scholper in JAMA 29:489-493, 2010) or Gilliam Autism Rating Scale (Gilliam, 2014). Males demonstrated greater difficulty in six CARS2-ST items and seven behaviours on the GARS-3, mostly reflecting restricted and repetitive behaviours. Across all instruments, the only area in which females showed greater difficulty was fear or nervousness (CARS2-ST). No meaningful differences emerged from the CARS2-HF analysis. Where males showed greater difficulty, females were more likely to present with developmentally typical behaviour.

An artificial intelligence approach for selecting effective teacher communication strategies in autism education

Effective inclusive education is key in promoting the long-term outcomes of children with autism spectrum conditions (ASC). However, no concrete consensus exists to guide teacher-student interactions in the classroom. In this work, we explore the potential of artificial intelligence as an approach in autism education to assist teachers in effective practice in developing social and educational outcomes for children with ASC. We form a protocol to systematically capture such interactions, and conduct a statistical analysis to uncover basic patterns in the collected observations, including the longer-term effect of specific teacher communication strategies on student response. In addition, we deploy machine learning techniques to predict student response given the form of communication used by teachers under specific classroom conditions and in relation to specified student attributes. Our analysis, drawn on a sample of 5460 coded interactions between teachers and seven students, sheds light on the varying effectiveness of different communication strategies and demonstrates the potential of this approach in making a contribution to autism education.