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By Jason Wolff, PhD

The corpus callosum is by far the largest white matter connection in the brain. We now have a great deal of evidence suggesting that connectivity is disrupted in autism. So when we think about connectivity across brain regions, the corpus callosum is an obvious target. There is a steady trend in the literature — dating back nearly two decades — suggesting that autism is associated with a smaller corpus callosum. It’s an important and fairly consistent finding.

If over a dozen studies have found a smaller corpus callosum in adults and older children with autism, would we see the same in infants? This was our main question. Somewhat surprisingly, we found the reverse of what has been seen later in life — in infants who developed autism, the corpus callosum was significantly larger. This result was evident even when we controlled for total brain size, which is known to be elevated in autism early in life.

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Corpus callosum enlargement was most evident at ages 6 and 12 months. The differences between babies with and without autism seems to go away by age 2, which we think is consistent with research showing a smaller corpus callosum in older children with autism relative to controls.

So our first set of results intrigued us. The corpus callosum was larger, and in particular thicker, in babies with autism. What could be causing this? Because the IBIS study collects multiple types of brain imaging, we were able to partially explore this question. We examined diffusion tensor imaging data, specifically a measure called radial diffusivity, to understand how white matter fiber structure might explain differences in corpus callosum size.

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We found that radial diffusivity very strongly predicted corpus callosum size in babies. This suggests that axon density and composition may explain group differences. For example, it is possible, that babies with autism have excess thin axons due to less pruning or early overgrowth. We can’t say for sure with these data, but we are very excited to pursue these results and are in the process of doing so through our ongoing Infant Brain Imaging Study.

If you have a child with autism and are expecting another child, please contact www.ibis-network.org. You can participate no matter where you live in the US and you can get a free evaluation and meet with a well-trained clinician.

Jason Wolff, PhD

Jason Wolff, PhD

By Jessica Bradshaw

As an Autism Science Foundation predoctoral fellow, I had the privilege of pursuing the answers to fascinating questions about the development of autism spectrum disorder in the first year of life. My research on very early interventions to encourage the development of pivotal social-communicative behaviors led me to questions of outcome measurement. How are we measuring such a complex system of behavior in young infants? How do we know if the intervention is working? How do we even know whether to intervene in the first place? How can we modify already well-established ASD interventions to work for the youngest infants? The questions became endless.

In an effort to make more sense of these seemingly infinite questions, I gathered all the research studies that implemented very early intervention for infants with or at-risk for autism from birth to 24 months of age. Only nine studies had scientifically documented the impact of that intervention in this very young population. Only nine studies! In reviewing and analyzing these studies, we found some answers about how to identify and intervene in early infancy and, of course, came up with even more questions.

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Jessica Bradshaw works with a client.

How do we know when to intervene?
Most researchers seemed to determine clinical concern for ASD based on both standardized measures (e.g., ADOS) and expert clinical judgment. Because toddlers typically begin using language between 12-24 months, delayed language is a primary risk factor for ASD around age two. At this age expert developmental clinicians were also able to notice atypical sensory and motor behaviors that may be associated with ASD. Infants under 12 months, however, proved to be tricky. Language is not expected at this age and repetitive behaviors and sensory interests are a part of typical infant development! Discerning symptoms of autism in these young infants have been notoriously difficult for researchers.

What are the treatments for infants and toddlers with or at-risk for ASD?
The use of behavioral strategies for improving social communication and decreasing challenging behaviors is the most established form of treatment for individuals with ASD thus far. As it turns out, intervention for infants is no different. Nearly all studies used a typical behavioral framework: provide an opportunity for the behavior (antecedent), wait for the infant to respond (behavior), and reward the child (consequence). Of course the studies did not report a standard “ABA” protocol in which the infant is sitting at a table while an adult presents them with different tasks. In my own studies using Pivotal Response Treatment (PRT), treatment sessions for children 0-5 years take place on the floor engaging in whatever activity motivates the child, like peek-a-boo or singing songs. In PRT, we find that motivating the child to interact and socially engage is pivotal in ASD intervention. It is easy to see how this type of naturalistic treatment strategy might be especially suited for infants.

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Does it work?
Ah, the million dollar question. These 9 studies were encouraging, but as for autism outcome – we need more research. Infants and toddlers tended to improve on target goals, but there was a lot of variability, calling into question the exact ingredients of treatment that are leading to improvements. Importantly, infants who started intervention earlier were found to make greater gains, re-confirming other findings (and our suspicion) that earlier intervention is better. Toddlers who received more hours of intervention also benefited more from treatment. Parents of all studies reported high satisfaction and enjoyment with these interventions, despite heavy parent involvement. It can be difficult for parents to interact with their toddler at-risk for ASD who is less socially responsive, and spending what can amount to 30-40 hours a week delivering interventions at home is exhausting. Interventions addressed this issue by teaching parents how to play and interact such that their child will be more interactive and engaged – and parents actually had fun doing it! This finding is key. The more we make our interventions feasible and enjoyable for parents, while also reducing parent stress, the more parents will use the treatment techniques and the more the entire family will benefit.

Prevention and intervention techniques for the youngest infants are rapidly growing and findings are burgeoning. These interventions are moving beyond the classic “ABA” model and incorporating elements related to developmental theory, self-regulatory processes, family systems, and parent-infant synchrony.  Recently, a paper was published by leaders in the field who agree that sometimes the names of the interventions can be artificial, since most are based in the same evidence-based methods of behavioral learning and developmental sciences. Schreibman et al. (2015) termed these interventions “Naturalistic Developmental Behavioral Interventions” and urge researchers to continue refining the active ingredients of treatment and testing its long-term impact in order to develop interventions that are most efficient and effective for families.

By Alycia Halladay, PhD

Earlier this week a study came out which examined the risk of autism after in vitro fertilization, or IVF. Data was pulled from California datasets, and it was among the largest study of its kind. A previous study using a nationwide database in Sweden had only shown an increase in risk after only specific types of procedures. In contrast, this latest study showed doubling the risk of ASD, without specifying what type of procedure was involved.

The study is important because there have been concerns about the outcome of children conceived via IVF. Because rates of IVF have increased over the past 2 decades, one of the concerns from parents has been the association between IVF and autism. This study showed a nearly 2x increase in autism risk after IVF, and that most of this increase risk was due to IVF related multiple pregnancies.  When the analysis excluded multiple births, the increased risk was no longer seen. The risk also significantly decreased when only women under the age of 35 were included in the sample.

One of the authors of the paper, Dr. Peter Bearman, was very bold in his conclusions of the study. He said, “Knowing that one can largely reduce the risk of autism by restricting the procedure to single-egg transfer is important for women who can then make better informed decisions.” Autism Speaks said in their report, “In recent years, reproductive medicine societies have recommended a general reduction in the number of embryo transfers, and this has reduced rates of multiple births.” First, there is no such thing as a “single-egg” transfer, so Dr. Bearman must have been referring to single-embryo transfer. Second, reproductive medicine societies have efforts in place to reduce the number of multiple births, not the number of transfers per se.

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For clarification, ASRM has specific guidelines on single embryo transfer, including only being appropriate for women under the age of 35. http://www.asrm.org/FACTSHEET_Elective_Single_Embryo_Transfer/. Second, the decision on how many embryos to implant are considered by both parents, not just women. Taken together, some of the comments around the study can make this issue confusing. Therefore, I thought it was important to get the perspective of a board certified physician on this issue, someone who is trained and trusted to counsel women who are undergoing this procedure.

Dr. Owen Davis, a board certified physician and president-elect of the American Society of Reproductive Medicine commented, “Multiple pregnancies are associated with many adverse pregnancy and birth outcomes, and the goal of physicians is to reduce the number of multiples while still ensuring the best chance for a successful pregnancy. The current guidelines set forth age and day of transfer as important variables. As age goes up, aneuploidy rates increase, and transfer of more than one embryo may be appropriate to ensure at least one goes on for a full term pregnancy.”

Therefore, the message to the autism community is: before you make any decisions about IVF based on autism risk, talk to your reproductive endocrinologist. Scientific studies should inform, not replace, those discussions.

By Emily L. Casanova, Ph.D. & Manuel F. Casanova, M.D.

Across many different fields of study, evidence is emerging that autism is a disorder caused by disturbances of early brain development. Over the last decade, autism research has strongly focused on synapse dysfunction, however a recent genetic analysis has revealed that while synapses are probably dysfunctional in autism, much earlier stages of brain development may be just as foundational to the condition.

In humans the production of new neurons continues up into the early part of the third trimester. By comparison, synapses, which are communicative junctions of neurons, are not established until the third trimester and continue to be remodeled throughout the lifespan. Current evidence stresses the importance of early brain development in autism risk, however it also raises an important question: Can both early and later brain development be affected in autism? Below is a schematic of the ways that neurons look during development, and then how they look when they are mature.

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Our laboratory has focused on the idea that many stages of brain development are affected in most cases of autism. In our most recent publication in Frontiers in Cellular Neuroscience, we report that most of the high-risk gene mutations associated with autism impair not only later synapse development but also earlier stages of neuron production and maturation. This tells us that autism is caused not only by dysfunctional synapses but by dysfunctional neural networks and neurons. This understanding is vital, not only so we can decipher how this heterogeneous condition develops, but also to be able to predict the different ways in which it might be treated or even prevented. In order to design successful treatments, we must know precisely what we’re dealing with.

Determining the ways in which the brain is affected in autism may also help us understand how different types of autism arise, and how these cases may be similar and/or different from typical forms of the condition. For instance, the childhood epilepsy known as Dravet Syndrome (DS) presents with normal or relatively normal cognitive development throughout the first year of life. Yet between ages 1-2 years these children develop seizures often in response to fever or illness. Following seizure onset, approximately 25% of these children also develop symptoms of autism, making DS a well-recognized form of syndromic autism. However, individuals with DS also exhibit brain malformations similar to those seen in typical and syndromic autism. Because these malformations occur very early in brain development, this indicates that DS, and perhaps other forms of regressive autism, have prenatal roots even though symptoms aren’t obvious until 1-2 years of age.

This work stresses the need for a paradigm shift in autism research and a broader understanding of how the brain develops. While it may be simpler to study a single structure or developmental stage, a tunnel-vision approach may not provide us with an accurate understanding of what has occurred to produce the condition we’re investigating. We hope that a broader developmental point of view is a step in the right direction, helping to bring together different branches of research so that their results complement each other rather than confuse the field. Autism, after all, is a puzzle. We need to be looking at all the pieces together.

A perspective by Lonnie Zwaigenbaum, MD

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With recurrence risk estimated as high as 20%, there are many families with more than one child with autism spectrum disorder (ASD). Advances in genetic testing, including availability of clinical microarray testing, with sequencing based technologies on the horizon, could potentially answer families’ questions about what caused their child’s ASD, and what might be the risk to younger siblings. However, a new study published this week, one of the largest to date to use whole genome sequencing (WGS), reports intriguing findings that challenge assumptions about transmission of genetic risk of ASD, and emphasize the complexity even within individual families.

A Canadian research group, led by Dr. Stephen Scherer, Director of the Centre for Applied Genomics in Toronto reported WGS of 85 multiple incidence families (two parents and two siblings with ASD). They found that in 36/85 (42%) of families, at least one child with ASD had DNA alterations potentially relevant to the disorder. However, only in 12/36 (33%) of these families were the same de novo or rare inherited ASD-risk variants identified in both siblings. In the other 24 families, the siblings carried different pathogenic mutations or one sibling had an ASD-relevant variant, and the other did not have one detected. Interestingly, siblings that shared risk variants tended to be more alike in their phenotypic features than those who did not share a risk variant.

At face value, such results seem counter to our assumptions that recurrence risk in siblings reflects shared genetic mechanisms.  Even at a population rate of 1 in 68 children, the odds of two siblings having differing genetic mechanisms for ASD would seem very low. However, there could be other as yet undetected genetic (or epigenetic factors) that account for occurrence in multiple siblings, despite not sharing specific risk variants at other loci. Indeed, the findings emphasize the potential importance of mapping variants across the entire genome to understand how multiple variants, independently or in combination, may increase vulnerability to ASD. And non-shared environmental factors may also be at play.

It does seem that if parents have a child with ASD in whom a specific genetic variant has been identified, it may not be sufficient to test their younger child just for that variant in order to determine likelihood of recurrence. As progress is made in WGS of a larger number of families, we will hopefully learn more about how complete sequencing (potentially in combination with other biomarker testing) may ultimately inform risk counseling.

 

Alycia Halladay, PhD, Chief Science Officer

2014 was a big year for autism research, and there have been a number of perspectives on the science of autism in 2014. In fact, the Simons Foundation did a beautiful job outlining some of the major scientific advances, hot topics, notable findings and new tools that were discovered or developed in 2014. Please take a look at their year end summary on their website, sfari.org. ASF would like to provide additional perspective on what has been accomplished in research and where science is leading.

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Synaptic, Transcriptional, and Chromatin Genes Disrupted in Autism

First, genetic findings made a major impact this year. Resources like the Autism Sequencing Consortium, the Autism Genetic Resource Exchange, the Simon Simplex Collection, and the Autism Genome Program were harnessed together to identify different types of mutations, and more importantly, map them out to see how they all fit together. After decades of identifying small or large mutations in single genes, the scientific field was ready to understand the relationship these genes had to each other, and to common pathways of function. The best examples of this were two papers published in Nature and Nature Neuroscience that were published in the last half of the year [1, 2]. They laid out the relationships between the different categories of genes associated with autism. One new category of genes was added that was not discovered until this year – it related to chromatin remodeling genes [3]. These are genes that don’t control protein synthesis, but actually decide how the DNA is shaped. Because you have enough DNA to reach the moon if it were unfolded and straightened out, the DNA needs to be stuffed into cells and shaped properly. An analogy to this is folded laundry. If the laundry isn’t folded properly, clothes wrinkle. Like laundry, if DNA isn’t folded properly, it doesn’t express proteins in the right way. Changes in gene expression without an actual change in the DNA sequence is called “epigenetics”, and this is an area of research that needs more study in autism. Given the findings this year and the role of environment in epigenetics (more on this later) it is likely to be something research will focus in on in 2015.

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Another important approach that was advanced this year was the use of sequencing in understanding genetics. Instead of looking at individual mutations of amino acids, the entire exome, or the code that directs protein synthesis, was sequenced [4]. Through this method, more genes related to autism were discovered and the way these mutations were passed on was identified. One of the major contributions from sequencing efforts was the confirmation that genes that are highly expressed in the brain are differentially affected in people with ASD [2]. There was a lot of work that went into this discovery. For example, how do we know what is a gene that is highly expressed in the brain and how do we know what happens in the brains of people with autism? For this, we need brain tissue. In 2014, The Simons Foundation for Autism Research (SFARI), Autism Speaks and ASF launched a new awareness and outreach campaign for a new and improved brain tissue collection program called Autism BrainNet. Instead of one collection site, there will be four, so hopefully, there will be four times the number of brains collected. Through brain tissue, we saw a number of important findings that may lead to treatments. It took decades to accumulate a dataset large enough to show that a type of immune cell in the brain, microglia, is turned on in relation to how brain cells that control neural function, are activated. There has been much research over the years on the role of microglia and the immune system in autism, and this relationship suggests that while activated microglia may not be the singular cause of ASD, it may reflect ongoing abnormal processes in brain function. The role of the immune system in ASD is another hot topic for research. In another breakthrough study, a group at Columbia showed that people with autism have an overabundance of dendritic spines. Dendritic spines are points on the neuron that make contact with other neurons [5]. They took their study a step further by then studying dendritic spines in an animal model of Tuberous Sclerosis, a disease with behavioral similarities to ASD. What was remarkable is that treating these animals with a drug called rapamycin reduced this overabundance of spines. If this line of research continues to move forward, there may be a new viable medication for autism symptoms that is linked to brain pathology. What we need is more research, and more brain tissue.

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Air traffic pollution mixes with genetic background to increase risk of ASD

This year, an important study was published confirming the interplay between an environmental exposure and an autism gene. (6) While studying genes and environmental exposures independently is important, scientists have agreed that it is the interaction of the two that may be important in ASD. In 2014, two published studies from the United States showed an association between high levels of air pollution exposure and increased autism risk [6, 7]. In a third, Heather Volk at USC showed that air pollution increases risk, but this risk was further elevated when a mutation in an autism gene is present. So, does air pollution cause autism? Maybe not, but clearly it’s a risk factor that doesn’t help brain development. As high levels of air pollution are associated with so many adverse health outcomes in children and adults, it’s hard not to argue it should be a target of prevention in ASD. And it’s something that is actionable – regulations in toxic release have improved air quality in the last two decades. Also, studies in China have reported changes in health biomarkers and neurodevelopmental markers with improvements in air quality [8]. But most importantly, this finding reveals that more studies need to be done looking at not just genetics, but gene/environment interactions. The role of the environment is especially interesting since environmental factors are known to act epigenetically, that is, they modify gene expression without changing DNA sequence. So now that a gene that modifies DNA expression without changing DNA sequence has been identified, there is a viable target to study.

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Participants at the sex and gender differences meeting in October

Participants at the sex and gender differences meeting in October

Who could leave 2014 without talking about the new, and much deserved attention to, the male sex bias in autism? In October, ASF and Autism Speaks co-organized a meeting to try to better understand the 4-1 male/female autism diagnosis ratio. A link to the podcast and the agenda can be found on the ASF website. A number of publications came out this year showing that females actually had a higher burden of genetic mutations compared to males, indicating something was “protecting” females from some autism symptoms [1, 9, 10]. If we could figure out what is protecting females, if they are protected in some way, could we bottle that for translational impact? On the other hand, are some females with autism just suffering in silence during childhood, only to be mis-diagnosed or underdiagnosed? This is an area that so deserves further study. Not just for the translational potential, but for better services for females with ASD.

Early Social Interaction project being delivered at home by parents

Early Social Interaction project being delivered at home by parents

Finally, some of the most impactful papers came from those studying the early detection and intervention of ASD and intervention across the lifespan. For example, for the first time, comprehensive behavioral interventions targeted at cognition and communication were delivered to infants as young as 6 months, with promising results [11] . Also, a low cost, easy to implement intervention for early motor behaviors showed promise in infants [12]. It’s still not clear if these interventions “prevent” autism emergence or diagnosis, but they do improve certain domains related to autism. Another long-awaited early intervention study in toddlers with ASD was published and showed efficacy of an intervention called “Early Social Interaction” which showed significant effects on adaptive behavior and autism symptoms compared to those who did not receive the same intervention. What was remarkable was that in this study, parents implemented the interventions at home, after being trained. [13]. But we know that not all people with ASD follow the same pathway of the same early symptoms with the same outcomes. This was demonstrated in the largest study of high-risk infants tracking behaviors from 1 ½ years to age of diagnosis[14]. Understanding how autism symptoms emerge will lead to specific interventions at early ages to improve skills for all people affected with ASD.

Pam Ventola from Yale enjoys delivering PRT to a child in her study

Pam Ventola from Yale enjoys delivering PRT to a child in her study

But the research didn’t just focus on infants and toddlers. The science around a behavioral intervention called PRT or pivotal response training in children and adolescents showed important advances. First, children of parents who were trained in PRT techniques showed improved outcome [15]. PRT was able to reverse the differences in brain activity seen in individuals with ASD. It also resulted in improvements in language and adaptive behavior [16]. Because of long waits for clinic-based approaches, interventions that are delivered by parents, caregivers and teachers need further data behind them, and need evidence-based adaptation for delivery. There are so many challenges behind getting caregivers and teachers to implement interventions at home or in the classroom setting, and figuring out ways in which this can be done better should be a priority for public health research in ASD.

The lives of people with ASD are made better through research. Before they can be declared “effective”, interventions have to be studied in real-life settings. Scientific findings must be discovered and then replicated to ensure that researchers are on the right path. This year’s collection of discoveries would not have been possible without researchers, scientists and research staff who dedicate their lives to helping people with autism; the families participating in research; all the people registering for post-mortem brain tissue donation; and individuals supporting science through their generous donation of funds. Thank you, and have a great 2015.

  1. Chang J, Gilman SR, Chiang AH, Sanders SJ, Vitkup D: Genotype to phenotype relationships in autism spectrum disorders. Nature neuroscience 2014.
  2. De Rubeis S, He X, Goldberg AP, Poultney CS, Samocha K, Ercument Cicek A, Kou Y, Liu L, Fromer M, Walker S, et al: Synaptic, transcriptional and chromatin genes disrupted in autism. Nature 2014, 515:209-215.
  3. Bernier R, Golzio C, Xiong B, Stessman HA, Coe BP, Penn O, Witherspoon K, Gerdts J, Baker C, Vulto-van Silfhout AT, et al: Disruptive CHD8 mutations define a subtype of autism early in development. Cell 2014, 158:263-276.
  4. Uddin M, Tammimies K, Pellecchia G, Alipanahi B, Hu P, Wang Z, Pinto D, Lau L, Nalpathamkalam T, Marshall CR, et al: Brain-expressed exons under purifying selection are enriched for de novo mutations in autism spectrum disorder. Nature genetics 2014, 46:742-747.
  5. Tang G, Gudsnuk K, Kuo SH, Cotrina ML, Rosoklija G, Sosunov A, Sonders MS, Kanter E, Castagna C, Yamamoto A, et al: Loss of mTOR-dependent macroautophagy causes autistic-like synaptic pruning deficits. Neuron 2014, 83:1131-1143.
  6. Raz R, Roberts AL, Lyall K, Hart JE, Just AC, Laden F, Weisskopf MG: Autism Spectrum Disorder and Particulate Matter Air Pollution before, during, and after Pregnancy: A Nested Case-Control Analysis within the Nurses’ Health Study II Cohort. Environmental health perspectives 2014.
  7. Kalkbrenner AE, Windham GC, Serre ML, Akita Y, Wang X, Hoffman K, Thayer BP, Daniels JL: Particulate matter exposure, prenatal and postnatal windows of susceptibility, and autism spectrum disorders. Epidemiology 2015, 26:30-42.
  8. Tang D, Lee J, Muirhead L, Li TY, Qu L, Yu J, Perera F: Molecular and neurodevelopmental benefits to children of closure of a coal burning power plant in China. PloS one 2014, 9:e91966.
  9. Iossifov I, O’Roak BJ, Sanders SJ, Ronemus M, Krumm N, Levy D, Stessman HA, Witherspoon KT, Vives L, Patterson KE, et al: The contribution of de novo coding mutations to autism spectrum disorder. Nature 2014, 515:216-221.
  10. Jacquemont S, Coe BP, Hersch M, Duyzend MH, Krumm N, Bergmann S, Beckmann JS, Rosenfeld JA, Eichler EE: A higher mutational burden in females supports a “female protective model” in neurodevelopmental disorders. American journal of human genetics 2014, 94:415-425.
  11. Rogers SJ, Vismara L, Wagner AL, McCormick C, Young G, Ozonoff S: Autism treatment in the first year of life: a pilot study of infant start, a parent-implemented intervention for symptomatic infants. Journal of autism and developmental disorders 2014, 44:2981-2995.
  12. Libertus K, Landa RJ: Scaffolded reaching experiences encourage grasping activity in infants at high risk for autism. Frontiers in psychology 2014, 5:1071.
  13. Wetherby AM, Guthrie W, Woods J, Schatschneider C, Holland RD, Morgan L, Lord C: Parent-Implemented Social Intervention for Toddlers With Autism: An RCT. Pediatrics 2014, 134:1084-1093.
  14. Chawarska K, Shic F, Macari S, Campbell DJ, Brian J, Landa R, Hutman T, Nelson CA, Ozonoff S, Tager-Flusberg H, et al: 18-month predictors of later outcomes in younger siblings of children with autism spectrum disorder: a baby siblings research consortium study. Journal of the American Academy of Child and Adolescent Psychiatry 2014, 53:1317-1327 e1311.
  15. Hardan AY, Gengoux GW, Berquist KL, Libove RA, Ardel CM, Phillips J, Frazier TW, Minjarez MB: A randomized controlled trial of Pivotal Response Treatment Group for parents of children with autism. Journal of child psychology and psychiatry, and allied disciplines 2014.
  16. Ventola P, Yang DY, Friedman HE, Oosting D, Wolf J, Sukhodolsky DG, Pelphrey KA: Heterogeneity of neural mechanisms of response to pivotal response treatment. Brain imaging and behavior 2014.

Pam Ventola, PhD
Yale University

This week we published a paper on the brain-based responses to a behavioral treatment for ASD, Pivotal Response Treatment (PRT). We set out to complete this project because in many areas in this country, not to mention around the world, there is a dearth of empirically validated treatment options for individuals with ASD. The literature on effective treatments for ASD is lagging behind work in other areas of the disorder; by design, treatment work is costly and time-consuming. It can take months or years to collect full data on a single child, depending on the length of the treatment. Furthermore, very few studies have sought to understand the mechanisms of treatment response, which is needed to understand how treatment works and to develop even more effective treatments that are tailored to individuals with distinct profiles.

Another thing that makes treatment research difficult is that no two cases of autism are exactly the same. The differences in how each case of autism shows itself as well as how they are biologically different has baffled autism scientists for years. In addition to treating ASD, we were assessing brain function in individuals in our study. Our brain-based data reinforced the notion of ASD as a heterogeneous disorder, but the magnitude of the heterogeneity was surprising even to us.

For the study, children completed a functional MRI (fMRI) before and after a four-month treatment course of pivotal response training. This is a behavioral therapy which is based in ABA and shown to improve some of the core symptoms of ASD. It is play based and targets critical, or “pivotal” areas like motivation, initiation of social interactions, and self management. The approach utilizes the motivations unique to each child to provide opportunities for skill acquisition within naturalistic play-based interactions. The fMRI allowed us to collect a measure of how the children processed social information and gave us images of which areas of the brain lit up, or were activated, during each task. This way, we were able to measure the strength of their brain-based responses to social information and the specific locations in their brains that responded. We found, before treatment even started, that two groups of children emerged. One showed increased activation, the other showed reduced activiation in the same brain are. This brain area is called the posterior superior temporal sulcus. This finding alone demonstrates biologically based subgroups of children with ASD, and suggests that these subgroups may reflect distinct biotypes (subgroups of children with a common aspect of their genotype).

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Following the four-month treatment course of PRT, children again completed an fMRI. Despite their differences in brain functioning, all of the children gained meaningful skills and showed improvements in adaptive, social and communication skills. Given that they showed different brain responses before treatment, this was somewhat surprising. What was the most exciting is that the children exhibited changes in brain functioning following the treatment. The treatment seemed to exert its effect in different ways depending on the child’s baseline brain-based profile. For example, the children who exhibited hyper-activation (too much activation) in the pSTS at the start showed a decrease in activation following treatment. The children who exhibited hypo-activation (too little activation) at the start showed an increase in activation in the pSTS following the treatment. This is the first work to demonstrate how brain-based responses to treatment may differ between groups of children with ASD. In this study, individuals with autism showed differences in biological markers. Yet behavioral based intervention showed improvements in both groups, reinforcing that individuals with ASD, despite how their brain is wired, can benefit from behavioral therapy.

This project, as a whole, is in its preliminary stages with this study representing our earliest neuroimaging data. Nonetheless, work such as this is crucial for children with ASD, their families, and care providers. As previously stated, understanding how and why treatments work is critical to bettering treatments and tailoring them to specific individuals. Specifically, this understanding will guide the refinement of existing treatments, inform the development of novel interventions, determine early efficacy indicators, and lead to the development of algorithms that predict which treatment will likely benefit a given person.

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