Research News

Scroll through recent research or click the category icon to the right of each title for similar research summaries. If you would like more background context on a particular piece of research, please click the link next to the “Reading Room Guide,” the small character at the bottom-left of each research story. He will transport you to the appropriate page in Autism Reading Room. You can access original publication sources and other popular media articles by clicking the news buttons at the bottom-right of each summary.

Omega-3 Fatty Acids Fail to Improve ASD Symptoms

By Shana R. Spindler, Ph.D. on April 8, 2015
omega-3 study_5

 

Background: According to a 2006 study, nearly 30 percent of children with autism use some form of omega-3 fatty acid supplementation. Omega-3 fatty acids are a special type of polyunsaturated fatty acid. They are highly concentrated in fish (in the form of DHA and EPA) and some plants (in the form of ALA), but can be taken in pill or oil form too. Because DHA is a critical factor in brain growth and development, research groups have investigated if omega-3 fatty acid supplementation can improve ASD symptoms.

 

While several studies report a decrease in hyperactivity among children who take omega-3 fatty acid supplements, in no study was this correlation significant. Adding to the confusion, many studies were very small and lacked randomized, double blind controls. Yet, despite a lack of scientific evidence showing effectiveness, omega-3 fatty acid use remains a staple in the ASD complementary and alternative treatment toolkit.

 

What’s new: On March 21, 2015, the online journal Molecular Autism published a study on DHA plus EPA supplementation for children (two to five years of age) with ASD in a randomized, double blind, placebo-controlled study. The researchers found no significant difference in core or associated symptoms between children receiving DHA and EPA versus placebo. They did, however, find a significant worsening of externalizing behaviors in the DHA plus EPA group. The researchers hypothesize that exacerbation of underlying gastrointestinal issues in the omega-3 fatty acid group may account for the significant worsening of externalizing behaviors.

 

Why it’s important: This study clearly indicates the lack of significant correlation between omega-3 fatty acid supplementation and ASD symptom improvement. The study also suggests that omega-3 fatty acid supplementation may worsen externalizing behaviors in children with co-occurring gastrointestinal issues, but this observation requires replication before conclusions can be made.


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Study Pinpoints Differences in Autistic Brain

By Chelsea E. Toledo, M.A. on March 31, 2015
2015_03_whole brain voxel

 

Background: Autism Spectrum Disorder (ASD) is characterized by differences in social interaction, communication, and behavior. Researchers have hypothesized that the functioning of—and communication between—related brain regions is atypical in people affected by the disorder. Their studies have largely focused on select areas of the brain, as opposed to observing them within the context of the entire brain system.

 

What’s new: On March 20, 2015, the journal Brain published a large study providing a whole-brain perspective of ASD versus typical development. The researchers used a grid-based technique to analyze the entire brain at once with data from existing functional Magnetic Resonance Imaging (fMRI) scans of the resting brain. They found that, in comparison to 509 typically developing individuals, the 419 participants with ASD showed differences in 20 key areas.

 

Why its important: The observed differences were in areas of the brain active in processing facial expressions, sense of self, and theory of mind—the ability to discern and predict other’s mental states. Future studies could leverage this technique to learn more about brain function in obsessive compulsive disorder, attention deficit hyperactive disorder, and schizophrenia.


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Brain Awareness Week 2015

By Shana R. Spindler, Ph.D. on March 16, 2015
Brain Awareness Week 2015

 

March 16-22 marks Brain Awareness Week 2015, a worldwide campaign coordinated by the Dana Alliance for Brain Initiatives and the Society for Neuroscience to promote the progress and benefits of brain research. Hundreds of international events are underway in celebration of this unique week.

 

Autism Reading Room offers extensive coverage of brain biology, from development to function, in our Brain Biology area. Check it out!


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Twin Study Finds Autism Risk Is Largely Genetic

By Chelsea E. Toledo, M.A. on March 11, 2015
2015_03_twin study genetic

 

Background: Autism Spectrum Disorder (ASD) affects about 1 percent children worldwide. Many children who are diagnosed have a sibling with ASD. Research has suggested that the disorder is heritable. While some researchers report that genetic factors are more predictive of ASD, other investigations suggest that environmental factors play an equal, if not larger, role.

 

What’s new: On March 4, 2015, the journal JAMA Psychiatry published a study of ASD in pairs of twins. The researchers recruited participants of a longitudinal study on identical twins, who share the same DNA, and fraternal twins, who have DNA similarity equivalent to non-twin siblings. After an initial screening of more than 6,000 twin pairs born in the United Kingdom between 1994 and 1996, the researchers conducted additional evaluations for ASD on smaller groups of twin pairs. They found that the identical twins were far more likely to share an ASD diagnosis. They also found that some environmental factors, such as living in an area with high air pollution, increased the risk of an ASD diagnosis—but that those played less of a role than genetic influences.

 

Why it’s important: Using a large cohort of twin pairs and a variety of diagnostic tools, the researchers have highlighted the genetic underpinning of ASD and ASD-related traits. Furthermore, they showed that the liability to ASD resides mainly in the additive effects of genetic factors. Future studies could probe genetic and environmental factors further—examining the predominance of ASD in boys and exploring possible interactions between genetics and the environment, for instance.


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ASD Subset More Sensitive to Mitochondrial Stressors

By Shana R. Spindler, Ph.D. on March 4, 2015
2015_03_mitochondria dysfunction

 

Background: Mitochondria, the microscopic powerhouses of cells, provide energy for cellular functions throughout the body and brain. Several studies have linked mitochondrial damage or dysfunction to complex neurological disorders, including autism. Both genetic mutations and environmental insults can disrupt mitochondrial function.

 

What’s new: On January 21, 2015, the Journal of Toxicology published a study looking at mitochondrial sensitivity to oxidative stress (when the body fails to eliminate damaging free radicals in the cell) in 19 children with autistic disorder (AD) and 19 control individuals. The researchers used a type of blood cell to make cell lines—where cells grow and replicate in a petri dish—for their study. All of the cells derived from AD children had a baseline level of mitochondrial dysfunction compared to controls. The researchers reported a subset of AD children (31 percent) whose cells exhibited remarkably abnormal mitochondrial function when exposed to ethylmercury, a chemical known to cause oxidative stress. The pretreatment of these cells with an antioxidant-boosting drug before ethylmercury exposure improved mitochondrial function.

 

Why it’s important: Ethylmercury is most famous for its role as a metabolite of thiomerisal, the controversial preservative in some vaccines. The take home message from this study is not that ethylmercury—or a vaccine—causes autism, but that a subset of autistic individuals may be more sensitive to environmental stressors, such as oxidative stress, due to abnormal mitochondria function in cells. The authors of the study are quick to point out that any assumptions made about ethylmercury exposure in the living person based on these in vitro cell results would be “overstating and unsubstantiated.” Why the mitochondria of these individuals is more sensitive, and how that may affect brain function, remains an open question.


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Behavioral Training May Normalize Brain Dysfunction

By Chelsea E. Toledo, M.A. on February 25, 2015
2015_02_auditory training

 

Background: Research suggests that both genetic and environmental factors play a role in the development of autism spectrum disorder (ASD), which is characterized by differences in brain function and behavior. Multiple studies have pointed to antidepressants as a possible environmental factor, proposing that exposure to the drugs in the weeks before and after birth could induce ASD symptoms in children. In some animal models of autism, researchers expose rats to antidepressants to mimic the behavioral effects seen in children.

 

What’s new: On February 2, 2015, the journal Proceedings of the National Academy of Sciences published a study examining the effects of behavioral training on rats exposed to antidepressants shortly after birth. The researchers found that the rats behaved similarly to children with ASD—preferring to play alone than with other rats, for example. Using a set of sounds shown to drive changes in the brain in typically developing animals, the researchers observed that, at first, rats exposed to antidepressants scored poorly on cognitive tests—and had underlying brain dysfunction. Over the course of two months—the rough equivalent of two years for people—the rats continued the auditory training and showed significant improvement in their behavioral responses and some reversal of their brain dysfunction, as well.

 

Why its important: The effect of antidepressant exposure affected male rats much more than females—a pattern that mirrors the prevalence of ASD in the human population, in which boys are four times more likely than girls to receive a diagnosis. The study also positions behavioral training that targets brain function as a possible therapy for children with ASD.


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Oxytocin Improves Eye Contact

By Sharmila Banerjee-Basu, Ph.D. on February 18, 2015
2015_02_oxytocin eye contact

 

Background: Oxytocin is a hormone produced in the brain with diverse physiological functions: labor contractions during childbirth, lactation, and sexual intimacy. More recently, scientists have examined oxytocin’s role in mediating social behaviors across mammalian species, including human. At present, oxytocin is an attractive pharmaceutical candidate for disorders of social cognition such as autism spectrum disorder (ASD).

 

What’s new: In a study published online, February 10, 2015, in the journal Molecular Psychiatry, scientists at University of Cambridge, UK, reported the effect of oxytocin in improving eye contact in a real-word social situation in adults with autism. The researchers administered an intranasal spray consisting of either oxytocin or placebo (same formulation without oxytocin), in a double-blinded manner, to 32 adult males with ASD and 34 neurotypical control participants. A novel test for social interaction – recording eye movements in a naturalistic setting – indicated that oxytocin significantly improved eye contact in both the ASD and control population. Importantly, oxytocin had a greater effect on looking time in ASD individuals with poor eye contact than in the placebo condition.

 

Why it’s important: Ongoing clinical trials are testing if therapeutic oxytocin can alleviate social cognition difficulties in children and young adults with ASD. This is the first study to show improvement of a core behavioral component of autism: eye contact in a social situation.


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Researchers Probe Blood Biomarkers for ASD

By Chelsea E. Toledo, M.A. on February 9, 2015
2015_02_09_blood

 

Background: At present, the only way to diagnose autism spectrum disorder (ASD) is through a series of behavioral screenings administered by trained professionals. While no laboratory test for ASD is currently available, recent studies have suggested that certain features detected in the blood could prove reliable as biomarkers for the disorder.

 

What’s new: The January 2015 issue of Neuroscience included a study evaluating two components in blood, serotonin and interleukin-6, as biomarkers for detecting ASD. While serotonin helps to regulate mood, interleukin-6 plays a role in the body’s inflammatory response to invading pathogens. The researchers performed blood tests on a total of 66 individuals—35 with ASD and 31 with typical development—whose average age was 12. They found that levels of serotonin and interleukin-6 were significantly elevated in the individuals with ASD, and were highest in those with the most severe forms of the disorder.

 

Why its important: The study found that, when taken together, serotonin and interleukin-6 were very reliable biomarkers for ASD—as blood tests looking for both molecules were accurate nearly 90 percent of the time. This work could lead to a clinical blood test for ASD risk, and could point the way to treatments targeting serotonin and interleukin-6.


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Tiny Air Pollutants During Pregnancy Increase ASD Risk

By Shana R. Spindler, PhD on January 30, 2015
pollution

 

Background: While genetic factors play a significant role in Autism Spectrum Disorder (ASD), several studies have pointed to air pollution as a potential  environmental contributor to ASD risk.

 

What’s new: On December 18, 2014, the journal Environmental Health Perspectives featured a study exploring the correlation between ASD and air pollutant exposure before, during, and after pregnancy. The researchers found that exposure to particulate matter less than 2.5 micrometers in size—about 1/30 the width of a hair—during the third trimester significantly associated with an increased risk of autism. Larger particulate matter (2.5-10 micrometers) and exposure before pregnancy, during the first and second trimesters, and after pregnancy were not strongly linked to autism.

 

Why it’s important: Three recent studies found similar results. The strengths of the current study include a relatively large sample size (245 cases and 1522 controls), sampling from across the United States, timing of pollutant exposure, and a focus on specific particulate matter. The type of air pollution associated with ASD risk in this study is produced by all types of combustion, including car engines, power plants, and wood burning.


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Brief Observations Unreliable for ASD Diagnosis

By Chelsea E. Toledo, M.A. on January 22, 2015
observation

 

Background: Although studies have identified differences in children with autism spectrum disorder (ASD) appearing as early as infancy, the behavior of very young children with ASD could match that of typically developing counterparts at times. With age, atypical behaviors appear with increasing frequency in children with ASD. This pattern is potentially problematic for families seeking early diagnosis, as the behavioral observations considered in clinicians’evaluations of children are usually quite brief.

 

What’s new: The February 2015 issue of Pediatrics included a study exploring the efficacy of brief behavioral observations for identifying children with ASD. The researchers conducted evaluations for a total of 44 children between the ages of 15 and 33 months, administering multiple questionnaires and observations to assign them to one of three groups: ASD, language delay, and typical development. Two psychologists specializing in early childhood development then watched 10- to 30- minute videos of the children to make their own evaluations. The researchers found that the experts were unable to catch 39 percent of the ASD cases from the brief observations alone, as the children with ASD demonstrated typical behavior 89 percent of the time.

 

Why it’s important: This is the first study to measure the extent to which young children with ASD can exhibit typical behavior. It suggests that any atypical behaviors appearing in observations merit follow-up and additional screening.


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Autism Increase Attributed to Reporting Practices

By Chelsea E. Toledo, M.A. on January 13, 2015
Diagnosis rates

 

Background: The United States Centers for Disease Control and Prevention estimates that 1 in 68 American children will receive a diagnosis of autism spectrum disorder, or ASD. The rate has increased significantly since autism first appeared in the Diagnostic and Statistical Manual of Mental Disorders in 1980.

 

What’s new: The January issue of JAMA Pediatrics featured a study examining autism prevalence in Denmark, where rates of ASD have also increased. Because of the country’s nationalized health system, the researchers were able to examine the records of all 677,915 Danish children born between 1980 and 1991, following up until 2011. They determined that two-thirds of the increase in ASD rates could be attributed to changes in the diagnostic criteria in 1994 and the inclusion of diagnoses from outpatient facilities in 1995.

 

Why it’s important: This is the first large-scale study to quantify the effect changes in reporting practices have on ASD rates. Future research could determine the cause of the increase not explained by changes in reporting practices, as well as the generalizability of these findings to other countries, such as the United States.


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Inflammation-Related Genes Ramped Up in ASD

By Chelsea E. Toledo, M.A. on December 23, 2014
innate immunity

 

Background: The root cause, or causes, of Autism Spectrum Disorder (ASD) remains unknown. Many studies point to a genetic component and have uncovered genetic glitches that appear in people with ASD. To understand how or whether those genes are expressed as traits, however, scientists would have to look for effects in the brain itself.

 

What’s new: On December 10, 2014, the journal Nature Communications published a large study on gene expression in the brains of people with ASD. The researchers examined 104 tissue samples from a total of 72 autopsied brains—47 from people with ASD and 57 controls with typical development. They found significant differences in gene expression within microglial cells, which respond to infectious agents and other threats that lead to inflammation in the brain. In the brains of people with ASD, they found that microglial cells were perpetually active, with genes for inflammation response turned on—likely a response to processes related to autism, and not the other way around.

 

Why it’s important: This is the largest data set examined to date on gene expression related to autism. Future studies could solidify whether treating inflammation could improve ASD symptoms.


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Scientists Piece Together Chemical Imbalances in ASD

By Chelsea E. Toledo, M.A. on December 11, 2014
serotonin and melatonin_5

 

Background: The chemicals serotonin and melatonin transmit important signals between brain cells. Serotonin helps to regulate mood, but it also converts into melatonin, an important regulator of sleep cycles. Previous studies have found separately that individuals with autism spectrum disorder (ASD) have elevated levels of serotonin and diminished levels of melatonin. That chemical imbalance is a suspected contributor to the behavioral and sleep issues observed in people with ASD.

 

What’s new: On November 11, 2014, the journal Translational Psychiatry published a study examining both chemicals—as well as N-acetylserotonin (NAS), the chemical serotonin becomes in the process of converting to melatonin. The researchers monitored levels of serotonin, NAS, and melatonin in the blood, platelets, and plasma, respectively, of 278 patients with ASD. When compared to 506 relatives unaffected by the disorder—as well as a control group of 416 people matched by age and sex—the group with ASD experienced significant disruption in the conversion of serotonin to NAS to melatonin. This disturbance was evidenced by high levels of serotonin and NAS and low levels of melatonin—with effects appearing most prominently in individuals with ASD and, to a lesser extent, in their blood relatives.

 

Why it’s important: This study sheds light on the relationship between serotonin, melatonin, and the intermediate chemical NAS as they relate to ASD. Future research can refine tests for disruptions in the level of these chemicals as biomarkers for the disorder. In addition, this study supports the possibility of melatonin as a therapeutic sleep aid for affected patients.


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Group Classes for Parents Yield Gains for Children

By Chelsea E. Toledo, M.A. on November 25, 2014
PRT_2

 

Background: Pivotal Response Treatment (PRT) is a child-led, play-based intervention intended to address target—or “pivotal”—areas of a child’s development, including motivation and initiation of social interactions. By focusing on these areas, PRT aims to induce broad social, behavioral, and communicative improvements in children with Autism Spectrum Disorder (ASD).

 

What’s new: On October 27, 2014, the Journal of Child Psychology and Psychiatry published the first-ever randomized controlled trial evaluating the effectiveness of PRT when administered by parents undergoing group training to deliver the intervention. A total of 53 children with ASD—aged two to six—participated in the study. Over the course of twelve weeks, parents of 27 children underwent group training to administer PRT in their homes, while the parents of the remaining 26 learned general information about ASD. Laboratory observations showed significant improvement in the number of utterances—such as saying “ball” to receive a ball—by children whose parents underwent PRT training.

 

Why it’s important: This study suggests that parents can become effective administrators of PRT after undergoing group classes—an efficient medium for disseminating information to a large number of affected families. Future studies could better examine PRT impact on social skills and determine the ideal balance of clinical interventions and at-home therapy.


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Researchers Search for Autism Blood Test

By Chelsea E. Toledo, M.A. on November 15, 2014
blood test

 

Background: Studies have shown that children with autism spectrum disorder (ASD) experience better outcomes the earlier they receive a diagnosis. Using currently available assessments—which include evaluations of language, behavior, and intellectual abilities—clinicians diagnose children with ASD at the average age of four.

 

What’s new: On November 7, 2014, the open-access journal PLoS One featured a study exploring techniques to find markers for ASD in the blood of affected individuals. The researchers compared the blood plasma of 39 children with ASD to that of 22 typically developing peers and found 179 features differentiating their blood. Using five different laboratory tests, the scientists tested for those same features in the blood of another set of children—13 with ASD and 8 with typical development—and were able to accurately classify them more than 80 percent of the time.

 

Why it’s important: This study moves the field closer to having a blood test for ASD, which would allow for earlier diagnosis and intervention. Future studies could refine which combination of biomarkers and which laboratory tests result in the most accurate diagnosis.


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Updated Catalog of Autism Genes Unveiled

By Sharmila Banerjee-Basu, PhD on November 4, 2014
new risk genes

 

Background: Autism Spectrum Disorder  (ASD) is a genetically heterogeneous condition in which hundreds of genes have been associated with the disorder. Large consortiums of scientists are working together to better define the genetic underpinnings of autism. An unmet challenge in the field is how to connect the genetic profile to clinical features of ASD—a necessary first step for targeted treatment.

 

What’s new: Two research groups report an updated list of ASD risk genes based on statistical analysis that quantifies the genes’ role in the October 29, 2014, online issue of Nature. Both groups utilize exome sequencing—where scientists read only the protein coding part of the genome—to sequence the DNA of individuals with ASD and controls. The larger study, led by an International Consortium, sequenced 3,871 ASD cases and 9,937 controls. The other study analyzed more than 2,500 families with a single child affected by ASD from Simons Simplex Collection. Together, the studies reveal an updated list of ASD-associated genes, including several novel genes.

 

Why it’s important:  The new studies have advanced our understanding of autism by replicating earlier findings of excess, spontaneously arising genetic glitches—known as de novo mutations—in ASD individuals. Another key finding addresses the gender bias in autism: ASD females and ASD males with low IQ have a different genetic risk architecture than ASD males with high IQ. Finally, the risk genes belonging to individuals with severe ASD significantly overlap with risk genes identified in Schizophrenia and Intellectual disability.


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Chemical in Broccoli Sprouts May Inform ASD Treatment

By Chelsea E. Toledo, M.A. on October 24, 2014
broccoli sprout_2

 

Background: No approved pharmacological treatment exists for the core symptoms of Autism Spectrum Disorder (ASD), which include impaired communication, difficulties with social interaction, and repetitive behaviors. However, some naturally occurring chemicals have been shown to address biochemical irregularities – such as oxidative stress – that are associated with ASD.

 

What’s new: On October 13, the Proceedings of the National Academy of Sciences published a double-blind study investigating the potential of sulforaphane – a chemical present in vegetables like broccoli sprouts, kale, and bok choy – to ameliorate autism symptoms. The researchers gave sulforaphane supplements extracted from broccoli sprouts to 29 young men between the ages of 13 and 27 over a period of 18 weeks, and compared them to a group of 15 men receiving a placebo. After 18 weeks, the group receiving sulforaphane showed significant improvement in their scores on three different behavioral assessments administered by caregivers and physicians, while the control group experienced little change. The researchers then stopped treatment and continued to observe both groups for four additional weeks, noting that their scores returned to the baselines established before treatment began.

 

Why it’s important: While many clinical studies aim to control ASD-related behaviors directly, this study addressed the suspected underlying biochemical abnormalities instead. Future studies could delve deeper into the possible benefits of sulforaphane – for instance, whether it can provide early treatment for young children with ASD diagnoses or if it might prevent ASD when taken as a prenatal supplement.


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New Hypothesis of ASD as a Disorder of Prediction

By Chelsea E. Toledo, M.A. on October 17, 2014
prediction

 

Background: Autism spectrum disorder (ASD) is characterized by difficulties with social communication and tendencies to engage in restrictive, repetitive behaviors. While those traits have been widely recognized, research has yet to determine whether they share a common, underlying cause.

 

What’s New: On October 6, the Proceedings of the National Academy of Sciences published a study describing a new hypothesis: that ASD symptoms stem from an inability to predict what’s coming next. The researchers suggested that people with the disorder experience events “as if by magic”—with the cognitive systems for linking one happening in their environment to another somehow compromised. While their hypothesis doesn’t explain every aspect of the autism profile, the researchers asserted their belief that predictive impairment underlay two of the most salient and seemingly disparate traits: difficulties with social communication and tendencies to engage in restrictive, repetitive behaviors.  For example, the same predictive impairment that inspires an individual to line up objects for comfort could also be at play when that individual experiences difficulty understanding intention of others. Finally, a reduction in motor anticipation could lead to atypical gesture and posture often observed in ASD children.

 

Why it’s important: This study provides a theoretical framework to explain various features of ASD. With this approach, researchers might be able to identify structures in the brain with differences ascribed to impaired predictive abilities.


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ASD Subgroup Linked to Brain Volume

By Shana R. Spindler, PhD on October 7, 2014
subgroup

 

Background: Autism Spectrum Disorder (ASD) features a diverse set of social and behavioral deficits, language abilities, and skill sets. Identifying unique subgroups in the ASD population is a major goal within the autism research community. Given that individuals within a subgroup may share causal risk factors, a subgroup diagnosis could enable targeted therapy options.

 

What’s new: Researchers in the United Kingdom have identified a subgroup of ASD based on language delay in childhood. The team used a technique called voxel-based morphometry to measure brain volumes in 80 adult men with ASD. Of the participants, 38 experienced childhood language delay with 42 reporting normal language development. Individuals with delayed language had an overall larger volume of brain grey matter than those with typical language histories. When the team measured specific brain areas, they found several clusters of decreased volume in those with language delay.

 

Why it’s important: Last year, the Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition (DSM-5) grouped anyone along the autism spectrum into a single diagnosis of ASD. This study highlights the need to assess individual traits within individuals on the spectrum as we work towards understanding the underlying biology of ASD subgroups.


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