The Autism studies/research thread

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Hope you did not get the idea ,that , I was in favour of a cure .. but am thinking from what ,I have seen may very. well be that a majority of Aspies suffer from inflammation in the body overall. Some more localized than others ,And it might be easier to deal with NTs if that was not affecting any Aspie ( even interacting with anything ). On a day to day basis ...And if there is a gene that affects inflammation, then that could help ND peeps, very possibly.

Children born with a common viral infection are nearly 2.5 times more likely to be diagnosed with autism spectrum disorder, a new study finds.

Cytomegalovirus is part of the herpes family of viruses. It spreads through body fluids like blood, saliva and urine, and it’s usually harmless in healthy people. Around a third of infected mothers pass CMV to their fetus in utero.

Researchers from Columbia and Vanderbilt universities, the University of Illinois Chicago and colleagues across the country are making steady progress in their decades-long quest to understand autism spectrum disorder (ASD), a brain development condition that affects social interaction, communication and behavior.

A target of their investigations is serotonin, a signaling molecule that is well known for its critical roles in regulating mood and which also plays an important role in the development of the brain and nervous system.

In a recent study, the researchers measured blood levels of serotonin in women whose children were diagnosed with ASD. Some of the children carried rare genetic variations that strongly contribute to the risk of autism, while others did not.

In their paper, published July 4 in the Journal of Clinical Investigation, the researchers reported that higher serotonin levels were primarily found in women whose children who did not carry the rare variants.

This finding suggests that elevated maternal serotonin levels are associated with autism in a subset of children who have multiple common genetic or environmental factors which likely contribute to risk. Elevated levels are not found as frequently when a single, rare genetic variant explains most of the risk.

The link between autism-associated genetic variations and maternal serotonin levels was first described more than 60 years ago.p

But it is a complicated picture that is not fully understood, noted James Sutcliffe, PhD, a pioneer in autism genetics at Vanderbilt University.

The study probed genetic samples from the University of Illinois Chicago (UIC) Autism Center of Excellence and from the UIC and Vanderbilt sites of the Simons Simplex Collection, a repository of samples from 2,600 families of children with ASD maintained by the Simons Foundation Autism Research Initiative.

The study did not have a control group — it did not compare maternal serotonin levels to those from women whose children do not have autism. Another limitation was that serotonin blood levels in the women were measured after their children had been diagnosed with ASD.

Taking measurements throughout pregnancy would provide a more complete picture of how maternal serotonin levels may relate to autism risk, said Jeremy Veenstra-VanderWeele, MD, the Ruane Professor of Psychiatry and director of the Division of Child & Adolescent Psychiatry at Columbia University Irving Medical Center in New York City.

Veenstra-VanderWeele is corresponding author of the paper. Before coming to Columbia in 2014, he directed the Division of Child and Adolescent Psychiatry at Vanderbilt University Medical Center and was medical director of the Treatment and Research Institute for Autism Spectrum Disorders (TRIAD) at the Vanderbilt Kennedy Center.

Sutcliffe, who co-authored the paper, is associate professor of Molecular Physiology & Biophysics and of Psychiatry & Behavioral Sciences at Vanderbilt.

Other co-authors are Edwin Cook, MD, also a pioneer in autism genetics who directs the Center for Neurodevelopmental Disorders and the Division of Child and Adolescent Psychiatry at UI Health, and colleagues from New York University and Yale University School of Medicine.

While the true nature of the relationship between serotonin levels and ASD remains elusive, clinical trials are underway at Vanderbilt and elsewhere to evaluate drugs that, by impacting the serotonin system, may relieve irritability or improve social functioning in children with autism.

Genetic studies also have led to the identification of other, possibly related health conditions in children with ASD, including previously undiagnosed cardiac abnormalities and severe epilepsy that occurs during sleep, Sutcliffe said.

Autism spectrum disorder (ASD) is quite prevalent, but its underlying mechanism is not well understood. In a recent study, researchers from Japan have found a significant link between the levels of specific dihydroxy fatty acids in umbilical cord blood and ASD symptoms. Their findings highlight the role of these metabolites in the developmental trajectory of ASD and could pave the way for early diagnostic techniques and a better understanding of ASD pathophysiology.

Although the exact causes of ASD are unclear, currently available evidence points to neuroinflammation as a major factor. Several studies in mouse models of ASD have hinted at the importance of polyunsaturated fatty acids (PUFA) and their metabolites during pregnancy in playing a key role in ASD development. PUFA metabolites regulated by the cytochrome P450 (CYP) affect fetal development in mice causing impairments closely linked to ASD symptoms. However, it is still unclear if the same is true for humans and needs further investigation.

To address this knowledge gap, a research team from Japan consisting of Professor Hideo Matsuzaki from the Research Center for Child Mental Development, University of Fukui, Dr. Takaharu Hirai at the Department of Psychiatric and Mental Health Nursing, School of Nursing, University of Fukui and Dr. Naoko Umeda from the Department of Maternal and Child Health Nursing, School of Nursing, University of Fukui, analyzed the CYP-PUFA levels in neonatal umbilical cord blood samples. Their study, published on July 23, 2024 in Psychiatry and Clinical Neurosciences, sheds light on the possible causes of ASD.

Sharing the motivation behind their study, Prof. Matsuzaki explains, “CYP metabolism forms both epoxy fatty acids (EpFAs), which have anti-inflammatory effects, and dihydroxy fatty acids, or ‘diols,’ which have inflammatory properties. We hypothesized that the dynamics of CYP-PUFA metabolites during the fetal period, that is, lower EpFA levels, higher diol levels, and/or increased EpFA metabolic enzymes would influence ASD symptoms and difficulties with daily functioning in children after birth.”

To test this hypothesis, the researchers investigated the link between PUFA metabolites in umbilical cord blood and ASD scores in 200 children. The cord blood samples had been collected immediately after birth and preserved appropriately, whereas ASD symptoms and adaptive functioning were assessed when the same children were six years old, with the help of their mothers.

After careful statistical analyses of the results, the researchers identified one compound in cord blood that may have strong implications for ASD severity, namely 11,12- dihydroxyeicosatrienoic acids (diHETrE), a dihydroxy fatty acid derived from arachidonic acid.

“The levels of diHETrE, an arachidonic acid-derived diol, in cord blood at birth significantly impacted subsequent ASD symptoms in children and were also associated with impaired adaptive functioning. These findings suggest that the dynamics of diHETrE during the fetal period is important in the developmental trajectory of children after birth,” highlights Prof. Matsuzaki.

More specifically, the researchers found that higher levels of the molecule 11,12-diHETrE had an impact on social interactions, whereas low levels of 8,9-diHETrE impacted repetitive and restrictive behaviors. Moreover, this correlation was more specific for girls than for boys. This newfound knowledge could be crucial in understanding, diagnosing, and potentially preventing ASD. By measuring diHETrE levels at birth, it may be possible to predict the likelihood of ASD development in children.

“The effectiveness of early intervention for children with ASD is well established and detecting it at birth could enhance intervention and support for children with ASD,” muses Prof. Matsuzaki. He also adds that inhibiting diHETrE metabolism during pregnancy might be a promising avenue for preventing ASD traits in children, although more research will be needed in this regard.

For the first time the Lindy Lab group has explored the effect of linguistic labelling in autistic children. The results of the study suggest that autistic children do not perceive concepts through language, so they have difficulty inferring that two objects given the same name form a category. In this respect, the need for further research into the relationship between language and concepts in the autistic mind is stressed.

“The autistic child population does not expect two objects, simply because they merely share a name, to have common properties or are the same type of object. They are not sensitive to categorisation through the language they are being offered,” said Agustín Vicente, Ikerbasque Research Professor and researcher in the UPV/EHU’s Lindy Lab group. “If the autistic population displays difficulties in deducing that two objects with the same name form a category, they may tend to generate concepts that do not coincide with those of the rest of the children and this may lead to difficulties in communication, among other things,” added Vicente.

During their childhood neurotypical individuals, those who conform to the socially typical standards of cognitive and communicative behaviour, are sensitive to the so-called linguistic labelling effect. Let’s take two different types of hoovers as an example: “If we tell a neurotypical child that a Dyson and a Roomba are two hoovers, they will expect them to do the same thing, in this case hoover. But if we don’t tell them and simply call one a Dyson and the other a Roomba, if they see us hoovering with the Dyson, they may not expect that we can also hoover with the Roomba,” explained Vicente.

“By assigning a linguistic label, a name, to it, a link is established between the properties of that object and the assigned label,” added Sergio Parrillas, a pre-doctoral researcher in the UPV/EHU’s Lindy Lab group. “When shown a second object with the same label, regardless of how different it may be from the first object or similar to it, the child expects it to perform the same function, in this case to hoover. However, if they are presented with a very similar object, but with a different label or name, they do not generalise the hoovering function to the new object, and interpret them as belonging to different categories.

So “sharing a name is a more powerful categorisation criterion than having a similar appearance. This phenomenon is important because it acts as a source of concept acquisition through language”, stressed the UPV/EHU researcher.

In neurotypical children this occurs from the age of 10 months onwards, and this study aimed to find out whether the acquisition of concepts through language also occurs in children on the autistic spectrum aged between 3 and 9 years.  The results suggest that, in contrast to neurotypical children, no sensitivity to the labelling effect could be identified in the autistic child population.

The linguistic labelling effect is an important source of concept acquisition and may predict important aspects of language development, such as acquisition and range of vocabulary.

Scientists in China have engineered monkeys with a human autism gene and symptoms, in the hopes of unlocking a treatment for the debilitating but little-understood disorder, a study said Monday. The "transgenic" macaques behaved similarly to humans afflicted with autism, the team wrote -- making repetitive gestures, and displaying anxiety and poor social interaction. This meant they could serve as a reliable animal model for researching the causes of, and possible cures for, autism in humans -- a feat welcomed by other specialists not involved in the study. "Our findings pave the way for the efficient use of genetically engineered macaque monkeys for studying brain disorders," the authors asserted. Until now, animal studies of autism have relied mainly on lab mice -- a species very far removed from humans in terms of genes, behaviour and physiology. So the team led by Zilong Qiu of the Institute of Neuroscience in Shanghai, created special test tube monkeys, giving them multiple copies of the MECP2 gene thought to be linked to autism in humans. The monkeys were borne by surrogate females, and their behaviour studied as they grew up. The researchers observed "an increased frequency of repetitive circular locomotion, increased anxiety, reduce social interaction", among other behaviours.

One of the monkeys transferred the transgene to its offspring, which also displayed autistic behaviour -- strengthening the hypothesis of a genetic root for autism, the study authors said. Qiu said the team would now scan the brains of their monkeys to try and identifiy circuit deficiencies. "Once we identify this brain circuit (problem) associated with the autism-like behaviour, we will use therapeutics such as gene editing tools... to manipulate this MECP2 transgene in the transgenic monkey," he explained. They could then begin to test potential treatments in the macaques -- members of the closely-related primate family -- a first step towards a possible human drug or therapy. Qiu insisted the team's methods met international ethical standards. Other scientists hailed the study as an "exciting development". "Developing sophisticated animal models of autism has always represented a significant challenge for scientists," said James Cusack, research director at the autism charity Autistica. "This excellent research has developed a more sophisticated model of autism which may further our understanding of autism and could eventually lead to the development of more tailored treatments," he said through the Science Media Centre. University of California psychiatry professor Melissa Bauman said the work "opens the possibility to explore genetic risk factors in a species more closely related to humans."

Florey researchers have found evidence of higher levels of the plastic chemical bisphenol A (BPA) in pregnant mothers who gave birth to sons with autism.

Research published in Nature Communications, led by Florey scientists Dr. Wah Chin Boon and Professor Anne-Louise Ponsonby, supports the hypothesis of a possible link between autism and exposure to plastic chemicals in the womb.

Professor Ponsonby said the researchers analyzed two large birth cohorts—the Barwon Infant Study (BIS) in Australia and the Columbia Center for Children's Health and Environment in the U.S..

"Exposure to plastic chemicals during pregnancy has already been shown in some studies to be associated with subsequent autism in offspring," Professor Ponsonby said.

"Our work is important because it demonstrates one of the biological mechanisms potentially involved. BPA can disrupt hormone controlled male fetal brain development in several ways, including silencing a key enzyme, aromatase, that controls neurohormones and is especially important in fetal male brain development. This appears to be part of the autism puzzle."

The study examined children with lower levels of the enzyme aromatase, which in the brain converts testosterone to neuroestrogen, Professor Ponsonby said.

The link between BPA presence and autism was particularly evident in the top fifth of boys with vulnerability to the endocrine-disrupting properties of this chemical. That is, those with lower levels of the enzyme aromatase. The study found boys in that group, who were born to mothers with higher urinary BPA levels in late pregnancy were:

3.5 times more likely to have autism symptoms by age 2 years.

6 times more likely to have a verified autism diagnosis by age 11 years than those whose mothers had lower levels of BPA during pregnancy.

In both birth cohorts, mechanistic evidence demonstrated higher BPA levels were associated with epigenetic (gene switching) suppression of the aromatase enzyme overall.

In laboratory work, Dr. Boon studied the impact of prenatal BPA on mice.

"We found that BPA suppresses the aromatase enzyme and is associated with anatomical, neurological and behavioral changes in the male mice that may be consistent with autism spectrum disorder," Dr. Boon said.

"This is the first time a biological pathway has been identified that might help explain the connection between autism and BPA," she said.

Professor Ponsonby said BPA, similar bisphenols and other plastic chemicals with endocrine-disrupting effects are now widespread and almost impossible for individuals to avoid.

"We all ingest plastic chemicals in many ways—through ingesting plastic food and drink packaging, inhaling home renovation fumes, and through the skin from sources such as cosmetics. There are so many ways these chemicals enter our bodies, so, it's not surprising that BPA was present in a large proportion of the women's urine samples we studied. It's important for us to understand how these plastics affect our health," Professor Ponsonby said.

These findings are now feeding into public safety regulators which update safety recommendations on manufactured chemical exposure, including plastic chemicals, during pregnancy and early life.

The team also looked for ways to reduce the adverse effect of BPA on the aromatase system.

Dr. Boon added that a type of fatty acid called 10-hydroxy-2-decenoic acid tested in mice could be worth further investigation.

Abstract
Male sex, early life chemical exposure and the brain aromatase enzyme have been implicated in autism spectrum disorder (ASD). In the Barwon Infant Study birth cohort (n = 1074), higher prenatal maternal bisphenol A (BPA) levels are associated with higher ASD symptoms at age 2 and diagnosis at age 9 only in males with low aromatase genetic pathway activity scores. Higher prenatal BPA levels are predictive of higher cord blood methylation across the CYP19A1 brain promoter I.f region (P = 0.009) and aromatase gene methylation mediates (P = 0.01) the link between higher prenatal BPA and brain-derived neurotrophic factor methylation, with independent cohort replication. BPA suppressed aromatase expression in vitro and in vivo. Male mice exposed to mid-gestation BPA or with aromatase knockout have ASD-like behaviors with structural and functional brain changes. 10-hydroxy-2-decenoic acid (10HDA), an estrogenic fatty acid alleviated these features and reversed detrimental neurodevelopmental gene expression. Here we demonstrate that prenatal BPA exposure is associated with impaired brain aromatase function and ASD-related behaviors and brain abnormalities in males that may be reversible through postnatal 10HDA intervention.

Background: Extensive research has documented the positive impacts of physical activity on children and adolescents with Autism Spectrum Disorders (ASD). However, the specific benefits of various sports on the social functioning of children with ASD remain ambiguous. This study aims to employ a network meta-analysis to investigate the effects of different sports on the social functioning of children and adolescents with ASD and to establish a ranking of their effectiveness.

Methods: This study conducted a comprehensive online search across Web of Science, PubMed, Cochrane, and Embase databases for randomized controlled trials and quasi-experimental studies focusing on social functioning outcomes. Data were synthesized using a Bayesian framework.

Results: Sixteen relevant studies encompassing 560 participants were included. According to Cohen’s classification, mini-basketball (SMD = 0.84, 95% CI: 0.46, 1.20), SPARK (SMD = 0.88, 95% CI: 0.06, 1.70), and Karate (SMD = 1.10, 95% CI: 0.27, 2.00) demonstrated high effect sizes, with Karate identified as the most effective intervention. Conversely, Combined Exercise and Nei Yang Gong interventions exhibited the least significant effects, falling below small effect sizes.

Introduction
As of 2020, the CDC reports that about 17% of children aged 3 to 17 have neurodevelopmental disorders. Among them, approximately 1 in 36 has autism spectrum disorder (ASD). ASD is a neurodevelopmental condition influenced by genetic, environmental, and immunological factors. It is marked by deficits in social functioning, repetitive behaviors, restricted interests, and executive functioning impairments. Social functioning deficits in children with ASD mainly affect language processing, non-verbal communication, and social cognition. These challenges hinder social interactions and extend to emotional regulation, self-care, and family dynamics. For instance, children with ASD may struggle with verbal communication, non-verbal social cues like facial expressions and body language, and understanding others’ intentions and emotions. These limitations restrict personal development and increase the caregiving burden on families. Therefore, providing targeted support and interventions is crucial to improve social functioning, education, daily activities, and social engagement.

The primary interventions for autism spectrum disorder (ASD) include pharmacological and behavioral strategies aimed at mitigating core symptoms, enhancing social functioning, and reducing related symptoms. Pharmacological approaches can have long initiation periods, delayed outcomes, and potential adverse effects on overall health. Behavioral interventions for children with ASD include Sensory Integration Training (SIT) for sensory adaptation; the Denver Early Start Model (ESDM) for improving language and social skills Naturalistic Developmental Behavioral Interventions (NDBI) and Parent-Mediated Interventions (PMI) which facilitate learning in daily activities. Cognitive Behavioral Therapy (CBT) has shown efficacy in emotion regulation; and Social Skills Training (SST) concentrates on enhancing social competencies. However, these methods often require significant time, financial resources, and expertise. For example, ESDM and NDBI need prolonged professional involvement, PMI demands extensive parental engagement, CBT may not suit children with limited cognitive abilities, and SST skills can be hard to apply in real-world settings. Conversely, exercise interventions improve physical health, enhance social interactions, reduce behavioral issues, and support neurodevelopment. Exercise-based approaches are more cost-effective, easier to integrate into daily routines, and less burdensome for families. Physical activities can also improve family interactions and emotional bonds, creating a more enjoyable learning environment for children with ASD. Thus, given the benefits and limitations of different strategies, exercise intervention stands out as a straightforward and viable alternative.

Lopez-Diaz employed football as an intervention and observed significant enhancements in social skills, emotional responses, feelings, and interpersonal problem-solving abilities following a 17-week program with 13 children diagnosed with ASD, in comparison to baseline measurements. Similarly, diverse forms of physical activity, including Karate, judo, Aquatic sports, and Combined sports have demonstrated substantial improvements in the social functioning of children with ASD. Although numerous studies have corroborated the positive effects of exercise on the social functioning of children with ASD, direct comparisons between different exercise interventions remain scarce. Traditional meta-analysis methods face inherent challenges when comparing the efficacy of various interventions. Network Meta-Analysis (NMA), as an innovative approach, can integrate multiple interventions within a single analysis, leveraging both direct and indirect evidence for comparison. The primary advantage of this method lies in its ability to rank the effectiveness of various interventions based on a unified outcome measure and to calculate the relative efficacy probabilities for each intervention. The benefits of NMA include increased precision in estimating treatment effects. Even when direct comparisons are sparse or unavailable, NMA can still utilize all available evidence for comparison and analysis. NMA provides a more comprehensive analysis and understanding of the relative efficacy of multiple interventions by integrating data from various sources to create a connected network of comparisons. The impact of physical activity on various symptoms of children and adolescents with ASD has been widely studied, but researchers cannot directly compare all possible activities. In such cases, NMA can be used to analyze and compare the effects of different exercise interventions. Additionally, NMA can identify potential inconsistencies in the evidence and provide more reliable and robust estimates of treatment effects. In this study, the NMA method was used to compare the relative efficacy of different physical activities in improving the social functioning of children and adolescents with autism spectrum disorder (ASD). The goal is to identify the optimal physical activity intervention program.

Conclusion
This study explored the effects of different sports on social function in children with autism spectrum disorder (ASD) through a network meta-analysis. The results showed that physical activity intervention had a significant effect on improving social function in children with ASD, with karate, mini basketball, and SPARK interventions showing higher effect values. Karate has been identified as the most effective intervention measure. Future research should further explore the specific effects of different exercise programs to optimize exercise intervention programs for children with ASD.

Autism spectrum disorder has long been known to affect more boys than girls. But why this difference exists has remained a puzzle. A new study out of Sweden may provide some answers, suggesting that the underlying genetic factors contributing to autism might vary between boys and girls.

The study, published in JAMA Psychiatry, found that heritability — the proportion of variation in a trait attributable to genetic differences — was significantly higher in boys than in girls. This finding points to the possibility that boys and girls might develop autism through different genetic pathways.

The motivation behind the study stems from a long-standing observation that autism is more commonly diagnosed in boys than in girls, with boys being about four times more likely to receive a diagnosis. This significant difference in prevalence between the sexes has puzzled researchers for years.

Previous research has proposed various theories to explain this sex difference, including the female protective effect, which suggests that girls might need a higher genetic burden to develop autism spectrum disorder. Another theory, the greater genetic variability in males, posits that boys might be more susceptible to developing the disorder due to their broader genetic diversity. The study was motivated by a desire to test these theories.

“The causes of autism remain unknown, but genetic causes, inherited directly from the parents, also play a major role. No single gene can explain autism, but the disorder is believed to be influenced by multiple genes (polygenic) and often interacts with environmental factors. A key feature of autism is the skewed sex ratio, with a significantly higher risk for boys. However, it is unclear why males are more likely to be diagnosed than females,” said study author Sven Sandin, an associate professor at Icahn School of Medicine at Mount Sinai and a senior researcher at the Karolinska Institutet.

“One way to understand the sex difference is through differences in genetic variance – a model that has rarely been considered and that we tested in the current study using epidemiological methods. This model suggests that males have higher genetic variance than females, meaning that more males than females are randomly exposed to a higher genetic load. This could explain why males are more likely to be diagnosed with autism than females without invoking the female protective effect (FPE), a more commonly used theory to explain the skewed ratio in autism. According to FPE, females are more resilient than males and can withstand a higher genetic burden before being diagnosed. However, results from previous studies have shown inconsistent findings regarding the FPE, including a recent study we conducted.”

“Finding a useful biological model to explain sex differences in risk is critical to understanding the underlying biological mechanisms that lead to the development of sex-specific prevention strategies and treatments,” Sandin explained. “By better understanding the biological basis for sex differences in disease, we can also work to reduce health disparities between men and women. It can also help guide research into the development of sex-specific animal models to improve the translation of research findings to humans.”

To conduct this study, the researchers analyzed data from an extensive population-based registry in Sweden. The study included over 1 million children born between 1985 and 1998, all of whom were followed until they reached 19 years old. By focusing on a large cohort, the researchers aimed to generate more reliable estimates of heritability for both boys and girls. Importantly, they restricted the sample to children born to Swedish parents and excluded twins, as twins present additional complexities in genetic studies due to their shared genetic makeup.

Autism spectrum disorder diagnoses were identified through Sweden’s National Patient Register, which includes comprehensive records of all inpatient and outpatient diagnoses since 1987. Diagnoses were made based on standardized assessments conducted at regular medical and developmental check-ups. The researchers then calculated heritability using statistical models that considered both genetic and environmental factors.

The findings revealed that the heritability of autism was about 87% in boys, compared to approximately 76% in girls. This difference of 11% between the sexes is statistically significant and suggests that genetic factors play a more substantial role in the development of autism in boys than in girls. The researchers believe that these results could indicate different underlying causes for the disorder between the two sexes, with boys possibly being more vulnerable to genetic risk factors.

“We expected to see a greater difference in heritability between males and females with autism, as we expected non-additive genetic factors, such as gene-gene interactions or epigenetic modifications, to be more influential in females than in males,” Sandin told PsyPost. “However, our results suggest that additive genetic factors, such as single nucleotide variants, are still the major contributors to autism risk in both sexes, accounting for about 75% of the variance in females and 87% in males.”

The study’s results are significant because they challenge the prevailing notion that autism has the same genetic basis in boys and girls. The fact that heritability is higher in boys suggests that the genetic architecture of autism might differ by sex. This could mean that different genetic variants or combinations of variants are responsible for the development of the disorder in boys and girls.

The study is a step forward in understanding autism risk and guiding future research on sex differences in autism risk,” Sandin said, noting that “the study does not provide information about individual risk.”

Despite the study’s strengths, including its large sample size and population-based design, there are some limitations to consider. The study only included children of Swedish origin, which may limit the generalizability of the findings to other populations. Additionally, the study did not account for all possible environmental factors that could influence the development of autism, such as prenatal exposure to toxins or early-life stressors. While the researchers adjusted for certain variables, such as parental age, there may still be unmeasured factors that could affect the results.

“A single study, no matter how large or well done, cannot provide incontrovertible evidence,” Sandin said. “Therefore, this study must be replicated using data from other health systems and populations.”

Future research could build on these findings by exploring the specific genetic variants that contribute to the development of autism in boys and girls. Additionally, studies could investigate whether different environmental factors interact with genetic risk factors to influence the development of the disorder in each sex. Understanding these interactions could help identify more targeted interventions and treatments for autism, tailored to the unique genetic and environmental profiles of boys and girls.

The study also raises questions about the clinical implications of the findings. If boys and girls have different genetic pathways leading to autism, this could have implications for diagnosis and treatment. For example, it is possible that the current diagnostic criteria, which are based primarily on studies of boys, may not fully capture the way autism manifests in girls. This could lead to underdiagnosis or misdiagnosis of girls with the disorder. Further research could help refine diagnostic criteria to better account for these potential differences.

“This type of research relies on the availability of reliable data and modern epidemiological and statistical methods, applied by a large international network of experts in different fields, and can only be carried out with significant funding.”

The study, “Examining Sex Differences in Autism Heritability,” was authored by Sven Sandin, Benjamin H. K. Yip, Weiyao Yin, Lauren A. Weiss, Joseph D. Dougherty, Stuart Fass, John N. Constantino, Zhu Hailin, Tychele N. Turner, Natasha Marrus, David H. Gutmann, Stephan J. Sanders, and Benjamin Christoffersson.

Adults with autism spectrum disorder prefer to take on a following role rather than leading when engaged in social imitation tasks, according to new research. This preference was accompanied by notable differences in brain activity between individuals with autism and their neurotypical peers during these interactions. The study’s findings, published in the journal Social Neuroscience shed light on the unique social dynamics experienced by those with autism and underscore the importance of studying these interactions in realistic, dynamic settings.

Traditional research on ASD has often focused on individuals in isolation or in response to artificial stimuli, such as videos or images. While these studies have provided valuable insights, they may not fully capture the complexities of how people with autism interact with others in their daily lives.

The researchers behind the new study wanted to go a step further by exploring how individuals with autism engage in social interactions when they are actually interacting with another person. They were particularly interested in imitation, a fundamental social behavior that plays a key role in learning and bonding. Imitation is not just about copying movements; it’s also about understanding and connecting with the person being imitated.

“My research is focused on the biological basis of social cognition, particularly during interactive exchanges. In this context, I have developed multi-brain recordings (also known as hyperscanning) to demonstrate that social cognition is not just something that happens inside a single brain, but is a distributed process across brains and bodies,” said study author Guillaume Dumas, an associate research professor at the University of Montreal and the director of the Precision Psychiatry and Social Physiology laboratory in the CHU Sainte Justine Research Center.

“We have shown that social interaction not only changes intra-brain activity but also gives rise to inter-brain synchronization. This has significant implications for how we understand human cognition in all its diversity. In the context of autism, it is especially important to adopt an interpersonal perspective that focuses less on individual abilities and more on understanding alterations in social behavior as consequences of interpersonal processes.”

The study involved 40 participants, including 10 high-functioning adults with autism and 30 adults without the condition. These participants were divided into pairs, or dyads, which were either composed of two typical adults (control dyads) or one adult with autism and one typical adult (mixed dyads).

The participants were asked to perform a series of imitation tasks involving hand movements. In these tasks, one participant would lead by performing a hand movement, while the other would follow by imitating the movement. The participants were seated in separate rooms and could see each other’s hand movements on a TV screen, allowing them to engage in the imitation task as if they were face-to-face.

Throughout the experiment, the researchers monitored the participants’ brain activity using EEG hyperscanning. This method captures the electrical activity of the brain from the surface of the scalp, enabling the researchers to analyze how well the participants’ brain waves synchronized during the imitation tasks. The study focused particularly on the low-alpha and high-alpha frequency bands, which are associated with brain activity related to attention and cognitive processing.

Behaviorally, individuals with autism spectrum disorder showed a preference for following rather than leading during the imitation tasks. While this preference might seem minor, it suggests that people with autism might be more comfortable in social interactions where they can take a responsive role rather than initiating the interaction.

“Autism is not necessarily related to less interactive ability but rather a change in the way the interaction unfolds,” Dumas told PsyPost.

On a neural level, the researchers found significant differences in brain synchrony between the control dyads and the mixed dyads. In the control dyads, there was a high degree of synchrony in the low-alpha frequency band during the imitation tasks, indicating strong neural coupling between the two participants. This synchrony was much less pronounced in the mixed dyads, suggesting that the presence of an individual with autism in the pair disrupted the typical pattern of brain synchronization seen in neurotypical individuals.

Interestingly, the mixed dyads showed increased synchrony in the high-alpha frequency band compared to the control dyads. This finding suggests that the individuals with autism and their neurotypical partners might be using different cognitive strategies to navigate the social interaction, potentially requiring more mental effort or visual attention to maintain the connection.

The findings highlight “that autism is not just something inside one person,” Dumas said. “This is a relational condition.”

While this study provides valuable insights, it also has some limitations. The sample size was relatively small, with only 40 participants, and the group of individuals with autism was limited to high-functioning adults. This means that the findings may not fully represent the broader autism spectrum. Another limitation of the study is its reliance on EEG hyperscanning, which, while powerful, has its own set of challenges. For instance, EEG measures brain activity on the surface of the scalp, which can make it difficult to determine the exact brain regions involved in the observed synchrony.

“We are now studying a large cohort to replicate these observations on a larger scale and uncover additional markers at the physiological level, such as heartbeat and skin conductance,” Dumas said. “Our goal is to develop an interpersonalized approach to autism, embracing both the relational dimensions of this condition and the rich diversity of individuals. This could pave the way for a more preventive approach to mental health, through an understanding of individual profiles at biological, psychological, and social levels, while also designing a more inclusive society that facilitates the lives of the many ways of being in the world.”

The study, “Distinct social behavior and inter-brain connectivity in Dyads with autistic individuals,” was authored by Quentin Moreau, Florence Brun, Anaël Ayrolles, Jacqueline Nadel, and Guillaume Dumas.