Although autism-specific behaviors typically begin to appear around 12 months of age, researchers have long been searching for more early signs diseases. The discovery of a clear biomarker could provide an opportunity for early therapies that promote brain development in the crucial first year of a child's life. Identifying early differences in brain biology may also improve understanding of what exactly causes autism spectrum disorder (ASD). In some cases, the biomarker itself may become one of the targets in therapy to prevent or alleviate disease symptoms.
This year, researchers discovered distinctive differences in the connectivity patterns in the brains of children who later develop ASD. These differences appear as early as 6 months of age and remain noticeable until 2 years of age.
The study appeared in June 2012 in the American Journal of Psychiatry. It was led by Joseph Piven, PhD, and Jason Wolf, PhD, at the Developmental Disabilities Institute at the University of North Carolina, Chapel Hill.
As part of their Infant Brain Imaging (IBIS) study, the researchers looked at early brain and behavioral development in 92 children who had an older sibling diagnosed with autism spectrum disorder. These children were in a group increased risk on the incidence of ASD, which often has a genetic origin.
The researchers used a special type of magnetic resonance imaging (MRI) called diffusion tensor imaging to capture three-dimensional pictures of children's brain development at 6, 12 and 24 months of age. In addition, all infants received behavioral assessments at 24 months of age. At the time of behavioral assessment, 28 of 92 children met criteria for ASD.
Children who were diagnosed with autism showed significant differences in white matter development in their brains compared to those who were not diagnosed. White matter is made up of nerve fibers that connect various areas brain Observed differences in children subsequently diagnosed with autism suggested blunted development of these connections in the brain during early infancy before the onset of major clinical symptoms.
"A very interesting aspect of the findings was the fact that differences in the brain change over time," says Dr. Piven. “We see different differences at 6 months of age than we see at 12 and 24 months. "This may help us understand new evidence that autism symptoms unfold, or emerge, over time."
In addition, Dr. Piven's team observed these differences in all 15 white matter compounds they looked at. "This represents a remarkable convergence of evidence and strengthens our confidence in this finding," he said.
Previous research has shown that autism is characterized by abnormal connections between different zones brain In theory, this could explain the disruptions in communication and social behavior that are distinctive features RAS. For example, a typically developing infant, when trying to communicate something of mutual interest, uses a combination of gestures, humming, and eye contact. This requires simultaneous communication between several areas of the brain.
It is too early to say whether one form or another, according to Dr. Piven. But the findings could help develop better tools for predicting disease risk and perhaps measuring whether early intervention improves the brain's underlying biology.
“The discovery of early biomarkers provides hope for interventions before behavioral symptoms become apparent,” says study co-author Geraldine Dawson, Ph.D. Dr. Dawson is the chief scientific officer of Autism Speaks and a professor of psychiatry at the University of North Carolina. "Early intervention may increase the likelihood that therapy can reduce, or perhaps even prevent, the development of limiting symptoms of autism," she said. (See publication on the topic). Further research is also needed to understand what causes these differences in early development brain
Researchers from the University of Utah, USA, did important step to diagnosing autism using magnetic resonance imaging (MRI). In the future, these data may help doctors identify a similar problem in children at the earliest possible stage. early stage, which will increase access to treatment and improve the prognosis for people with autism.
The study results were published October 15 in the journal Cerebral Cortex, Medical News Today reports. Neuroradiologist Jeffrey S. Anderson, a professor of radiology at the University of Utah, led the study. He used MRI to identify areas where the left and right hemisphere brains in people with autism did not communicate correctly with each other.
These areas are "hot spots" that are associated with motor skills, attention, facial recognition and social behavior - all of which are impaired in people with autism. MRIs of people without autistic disorders did not reveal similar deficits.
"We know that the two hemispheres must work together to perform many brain functions," says Anderson. "We used MRI to evaluate the strength of these connections on both sides in patients with autism."
Besides bigger size The brains of young children with autism are not significantly different from those of people without the disorder, and routine MRI brain scans cannot detect autism. For a long time, many scientists have suggested that differences in the brains of people with autism can be discovered by studying how different parts of the brain interact with each other.
Another study from the University of Utah measured the microstructure of white matter, which connects different parts of the brain, and found significant differences in autism. This suggests that MRI may eventually become a tool for diagnosing autism. In this case, the diagnosis will be made based on objective and quickly obtained data, which will make assistance methods more timely and successful. The research may also lead scientists to new treatments for autism.
"We don't know what exactly happens to the brain in autism," said Janet Leinhart, a professor of psychiatry and pediatrics at the University of Utah and lead author of the study. "This work is an important piece of the autism puzzle. This is new evidence of functional disruptions in brain connectivity in autism that "brings us closer to understanding this disorder. When you understand something at a biological level, you can predict the development of the disorder, identify the factors that cause it, and influence it."
A growing body of research supports abnormal connections between different brain regions in autism. However, this study was the first to identify such functional disorders with a full brain scan using MRI. The study, which lasted a year and a half, involved 80 patients with autism aged 10 to 35 years. The results will add to an ongoing study that is following 100 patients with autism.
Scientists not only hope that in the future it will be possible to use MRI to diagnose autism, they expect that these data will help identify different biological varieties of autism. “This is a very complex disorder that simply cannot be described by one category,” says Leinhart. “We hope that this information will help us characterize Various types autism, whose symptoms and prognosis vary. As a result, we will be able to select best treatment for every single person."
Autism spectrum disorder (ASD) is a neurobiological developmental disorder that exhibits features of a qualitative impairment in social interaction (the Autism Spectrum Questionnaire (ASSQ) can be used to diagnose ASD).
ASD is characterized by core symptoms such as persistent deficits in social communication and social interaction across contexts, as well as restricted, repetitive patterns of behavior, interests, or activities. The fundamental phenotype of ASD is qualitative violation social interaction (generally accepted clinical point Over the past 30 years, various brain imaging studies have been conducted, including functional magnetic resonance imaging (fMRI), which can be considered as part of an effort to investigate the neural correlates of social deficits in ASD.
Among the results of MRI studies that go beyond simply assessing the brain in terms of structure and actually assessing the function of each brain region, allowing "examination in vivo", one of the most convincingly replicated findings is an abnormality in the so-called "social area of the brain."
The "social brain area" includes the superior temporal sulcus (STS) and its adjacent areas such as the middle temporal gyrus (MTG), fusiform gyrus (FG), amygdala (AMY), medial prefrontal cortex (MPFC), and inferior frontal gyrus ( IFG).
It is known that the “social area of the brain” plays an important role in social cognition, since it is a “reservoir” for the accumulation of cognitive processes necessary for understanding and interacting with other people. In many FMRI studies, a group of patients with ASD have been found to exhibit hypoactivation" social area brain" compared to a healthy control group.
To understand the social deficit of ASD (i.e. clinical features) and explain the results of brain imaging studies, it is necessary to simplify a number of basic processes of appropriate social interaction between people that are qualitatively deficient in patients with ASD. The first step is to recognize the emotion in the other person's facial expression. The next step is to experience and share emotional states another person, imitating and reproducing identified emotions in one’s own mind - the “empathic process”. In this regard, the concept of “empathy” can be defined as “an affective state caused by the exchange of emotions or sensory states of another person.” The next step after the empathic process is to consider the other person's perspective, understand the underlying situation and intention of the other person that caused a particular emotion or behavior, and predict and demonstrate appropriate responses. This is called the "mentalizing process" and is essential for successful social interaction.
Neural correlates that are known to be associated with the key social interaction processes mentioned above (i.e., empathy and mentalization) are included in the social brain region that shows anomaly in imaging studies of patients with autism spectrum disorder. In particular, the perception of emotional facial expression, which is the first step in understanding the internal world of another person, is a complex visual process that is accompanied by activation of anterior limbic areas (eg, AMY) and other cortical areas (eg, STS and cingulate cortex), and also activation of the FA, which is a selective region and is important for encoding facial features and recognizing facial identity. STS is known to play an important role in the visual analysis of dynamic aspects, particularly changes in facial expression. In the next step, to empathize with another person's emotions, it is important to carry out the process of modeling the other person's behavior and emotions through the mirror neuron system (MNS). In other words, when we look at another person who is expressing a certain emotion, we go through an internal imitation process through the activation of our MNS, and thus we can feel the emotions that the other person is experiencing “as if we ourselves had experienced the emotions.” These MNSs are also included in the IFG region of the social brain region. In addition, mentalization is the ability to understand the intention of another person's behavior and predict " mental states" another man. Regions that have been repeatedly identified as neural correlates relevant to mentalization based on fMRI studies using different paradigms are the pSTS/TPJ, temporal fields, and MPFC, which are also included in the “social brain” region.
When emotional facial stimuli are presented to children with autism spectrum disorder (ASD), various areas"social brain" related to social cognition show a decrease in their activity. Specifically, children with ASD show less activity in the right amygdala (AMY), right superior temporal sulcus (STS), and right inferior frontal gyrus (IFG). Activation of the left insular cortex and right IFG in response to images of happy faces is less in the ASD group. Similar results are found in the left superior insular gyrus and the right insula in the case of neutral stimulation.
Social cognition deficits in ASD may be explained by decreased ability to visual analysis "emotional persons", subsequent internal imitation through the mirror neuron system (MNS) and the ability to transfer it to limbic system to process conveyed emotions.
Various visual areas (e.g., fusiform gyrus, inferior and middle occipital gyri, lingual gyrus, etc.) are involved in the processing of emotional facial expressions. The results of the studies show that the ASD group does not show reduced activation of these visual areas compared to the control group, and when stimulated with a happy face, the ASD group shows a rather increased activation of Rt. in the occipital gyri compared to the control group. This can be interpreted as indicating that while visual perception and analysis are essential for successful social interaction, downstream processes such as internal imitation, emotional processing, and interpretation of another person's behavioral intentions are critical.
The insular cortex region plays a role in connecting to the limbic system (i.e., the "emotional center") and is necessary to sense another person's emotions as if it were one's own emotion, through internal imitation occurring in the MNS. Anatomically, the insula region is connected to both the MNS and the limbic system (for happy and neutral face image stimuli, the ASD group shows reduced activation of the insula region.
According to the "right brain hypothesis", the two hemispheres of the brain are specialized differently for processing emotions. In other words, the right hemisphere is uniquely qualified to process emotions, and left hemisphere plays a supporting role in emotional perception. It also appears that emotion-related tasks are divided between the two hemispheres of the brain, with the right hemisphere specializing in the perception of negative or avoidant associated emotions, while the left hemisphere is activated by emotions from positive experiences.
From a medical point of view, autism is complex medical condition With unclear etiology(i.e. reasons for occurrence). In my practice, I try to learn as much as possible about each patient. This requires a thorough examination of the child himself, detailed communication with parents about the medical history, as well as extensive laboratory tests.
Here's where I start my research:
- The actual reception of the patient: the standard ten minutes that the pediatrician graciously grants to the patient is completely insufficient here. Among other things, the conversation should include detailed description medications taken during pregnancy, a description of the food the child took and a story about older relatives: do grandparents and older parents have any quirks?
- Audiology: I had a patient from Canada whose hearing was not tested. The boy was deaf, but not autistic.
- MRI: I'm not a big fan of this procedure. First of all, you need to consider the risks posed by general anesthesia(without it, this study will not be possible, since complete immobility of the child is required). The main practical value of MRI often comes down to the fact that parents are a little encouraged: external signs There's nothing wrong with my brain.
- EEG: often the child does not show any visible seizures of epilepsy (loss of consciousness or muscle tremors). However, prominent doctors involved in the treatment of autism believe that testing brain rhythms (especially if also done during sleep) may have an impact. great value to promptly identify peaks of activity that may harm the brain.
And now the fun begins: You need to somehow convince the child to cooperate with you during the procedure. Then you need to find a good pediatric neurologist who will help decipher the data obtained. Then you need to decide whether to treat areas with increased electrical excitability, since neither anticonvulsant is not completely safe. A very difficult and time-consuming process. - Detailed blood test: very often pediatricians ignore this simple test. If we strive to ensure that the brain is sufficiently saturated with oxygen, we first need to understand whether the child is suffering from anemia.
- Assessing lead and mercury levels in a patient's blood: the theory that heavy metals may somehow be “locked” in the brain is controversial and has generated extensive debate in the medical community. But such a check often helps reassure worried parents. I oppose the introduction of a special provocateur into the body, which will cause the release of heavy metals, without first determining their basic level.
- Other metals: magnesium, calcium and zinc are very important for many substances in the body chemical reactions. Children who are picky eaters often miss out on the most important nutrients. Micronutrient deficiency can lead to skin rashes and digestive problems.
- Performance evaluation thyroid gland: I offer you a logical construction. We have a patient who demonstrates hyperactivity or, on the contrary, lethargy and loss of strength. How can we know that this condition is not related to thyroid health unless we get it checked? Correct answer: no way.
- Chromosomal analysis: Traditional school doctors too often tell parents that autism is genetic disease and treating it with any other means other than classes like ABA is useless. So why not check the chromosomes themselves? If everything is ok with them (by at least to the extent that modern genetics can confirm this), then, obviously, biomedical intervention has a significantly greater chance of success than is generally believed.
- Gastrointestinal health: I prefer to see a detailed coprogram and check the stool for dysbiosis in order to know for sure whether there is pathological growth pathogenic microorganisms(including yeast), and how the process of digestion of proteins, fats and carbohydrates occurs. By the way, potty training a child will be much easier when intestinal health is restored.
- Food allergies: when the body reacts to input from external environment agent by releasing immunoglobulins, goes inflammatory process, which undermines the overall energy of the body. Exclusion from food of dishes to which it has been identified increased sensitivity, will help remove the “fog” and establish eye contact and communication.
A gluten- and casein-free diet usually doesn't work in two cases: 1) The patient is not allergic to either gluten or casein; 2) The child continues to receive some third (fourth, fifth...) product to which he has an allergic reaction.
We check children for sensitivity to a very wide range of food products and we recommend not just any general diet, but a diet specially selected for a particular patient. You should also test your urine for traces of opiate-like substances, which have been linked to poor absorption of gluten and casein in the intestines. - Vitamin levels: It is especially important to know whether the patient is getting enough vitamins A and D from food. This is easy to find out and just as easy to solve with the help of multivitamin supplements.
- Metabolism knowledge: information about how well the patient's kidneys and liver are functioning should be familiar to the attending physician, since this determines the tolerability of many medications.
- Lipid panel: both tall and low level cholesterol can lead to health problems. If cholesterol is very low, this can easily be corrected with medication, often resulting in improvements in eye contact and communication. This information may also influence the composition of the diet used.
The journal Science Translational Medicine published the results of a study of the capabilities of magnetic resonance imaging (MRI) in diagnosing autism in 6-month-old children. An MRI study of brain connectivity in infants at high risk for autism was found to successfully identify nine of 11 children who were subsequently diagnosed with autism spectrum disorder (ASD) at age two. Moreover, neuroimaging data allowed us to correctly diagnose the norm in all 48 infants in whom the diagnosis of ASD was subsequently rejected. On this moment There is no generally accepted way to diagnose ASD before the onset of behavioral symptoms, but these new findings support the hypothesis that patterns of brain development predisposing to autism are present in children long before they develop typical ASD behaviors at approximately 2 years of age. According to the authors of this work, this opens up opportunities for early intervention, which may be significantly more effective than modern strategies corrections, which, as a rule, begin after two years, when atypical characteristics of the brain have long been formed.
This study was sponsored by National Institute children's health and Human Development, as well as the US National Institute of Mental Health. As part of this work, a team of scientists from the University of North Carolina and the Washington University School of Medicine tested a 15-minute scanning protocol called functional connectivity MRI (fcMRI) on 59 sleeping children with a high hereditary risk of ASD, namely those with older siblings with RAS. Having a sibling with autism is known to increase a child's risk of developing ASD to approximately 20%, while for children without siblings with ASD the risk is approximately 1.5%.
Estimated at this study Functional connectivity of the brain allows us to judge how different parts of the brain can function synchronously during the performance of certain tasks or at rest. As part of a larger project that has been ongoing for 10 years, the researchers collected a large number of data on 26,335 pairs of functional connections between 230 different brain areas. After scanning, the authors used a self-learning software to decipher fcMRI data. computer program, with the help of which algorithms were developed to identify patterns that were selected as predictors of ASD. Moreover, among all functional connections, those that correlated with at least one associated with ASD were selected. behavioral feature that were evident in study participants at the 24-month assessment (including social skills, speech, motor development, and repetitive behaviors). According to the comments of the authors of the work, from the picture obtained with fcMRI at rest, one can judge how different parts of the brain will interact under the most extreme conditions. various types activities - from limb movements to social interaction, and the very complex patterns that emerge can be both typical and atypical.
Overall, the diagnostic accuracy of the self-paced program for identifying infants who would go on to develop ASD using fcMRI was 96.6% (95% confidence interval [CI], 87.3% - 99.4%; P<0,001), с положительной предсказательной ценностью 100% (95% ДИ, 62,9% - 100%) и чувствительностью 81,8% (95% ДИ, 47,8% - 96,8%). Более того, в исследовании не было ложноположительных результатов . Все 48 детей, у которых впоследствии не было выявлено РАС, были отнесены в правильную категорию, что соответствовало специфичности 100% (95% ДИ, 90,8% - 100%) и отрицательной предсказательной ценности 96% (95% ДИ, 85,1% - 99,3%).
Of course, these are very early results, which will subsequently need to be confirmed in larger populations. In fact, one such study, the European Autism Interventions study, is already underway, also scanning the brains of at-risk infants to better understand the biology of ASD and ultimately develop pharmacological treatments.
In addition, according to the authors of the now published work, the fcMRI technique they used, followed by interpretation of the results by a self-learning computer program, is unlikely to ever be suitable for routine mass screening of infants. Most likely in the future as a screening for group identification high risk Some cheaper method will be used (for example, detecting DNA in the child's saliva), and neuroimaging techniques will be used in the second stage to confirm a very high risk of autism.
Loading...