Tag: autism spectrum disorder

Categories : Neurology PaediatricsTags :

Could a Simple Eye Reflex Test Pick up Autism in Children?

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Scientists at UC San Francisco that they may have discovered a new way to test for autism by measuring how children’s eyes move when they turn their heads. They found that children with a variant of a gene that is associated with severe autism are hypersensitive to this motion.

The gene, SCN2A, makes an ion channel that is found throughout the brain, including the region that coordinates movement – the cerebellum. Several variants of this gene are also associated with severe epilepsy and intellectual disability.

The researchers found that children with these variants have an unusual form of the reflex that stabilizes the gaze while the head is moving, called the vestibulo-ocular reflex (VOR). In children with autism, it seems to go overboard, and this can be measured with a simple eye-tracking device.

The discovery, published in the journal Neuron, could help to advance research on autism, which affects 1 out of every 36 children in the United States. And it could help to diagnose kids earlier and faster with a method that only requires them to don a helmet and sit in a chair.

“We can measure it in kids with autism who are non-verbal or can’t or don’t want to follow instructions,” said Kevin Bender, PhD, a professor in the UCSF Weill Institute for Neurosciences and co-senior author of the study. “This could be a game-changer in both the clinic and the lab.”

A telltale sign of autism in an eye reflex

Of the hundreds of gene mutations associated with autism, variants of the SCN2A gene are among the most common.

Since autism affects social communication, ion channel experts like Bender had focused on the frontal lobe of the brain, which governs language and social skills in people. But mice with an autism-associated variant of the SCN2A gene did not display marked behavioral differences associated with this brain region.

Chenyu Wang, a UCSF graduate student in Bender’s lab and first author of the study, decided to look at what the SCN2A variant was doing in the mouse cerebellum. Guy Bouvier, PhD, a cerebellum expert at UCSF and co-senior author of the paper, already had the equipment needed to test behaviors influenced by the cerebellum, like the VOR.

The VOR is easy to provoke. Shake your head and your eyes will stay roughly centered. In mice with the SCN2A variant, however, the researchers discovered that this reflex was unusually sensitive. When these mice were rotated in one direction, their eyes compensated perfectly, rotating in the opposite direction.

But this increased sensitivity came at a cost. Normally, neural circuits in the cerebellum can refine the reflex when needed, for example to enable the eyes to focus on a moving object while the head is also moving. In SCN2A mice, however, these circuits got stuck, making the reflex rigid.

A mouse result translates nearly perfectly to kids with autism

Wang and Bender had uncovered something rare: a behaviour that arose from a variant to the SCN2A gene that was easy to measure in mice. But would it work in people?

They decided to test it with an eye-tracking camera mounted on a helmet. It was a “shot in the dark,” Wang said, given that the two scientists had never conducted a study in humans.

Bender asked several families from the FamilieSCN2A Foundation, the major family advocacy group for children with SCN2A variants in the US, to participate. Five children with SCN2A autism and eleven of their neurotypical siblings volunteered.

Wang and Bender took turns rotating the children to the left and right in an office chair to the beat of a metronome. The VOR was hypersensitive in the children with autism, but not in their neurotypical siblings.

The scientists could tell which children had autism just by measuring how much their eyes moved in response to their head rotation.

A CRISPR cure in mice

The scientists also wanted to see if they could restore the normal eye reflex in the mice with a CRISPR-based technology that restored SCN2A gene expression in the cerebellum.

When they treated 30-day-old SCN2A mice – equivalent to late adolescence in humans – their VOR became less rigid but was still unusually sensitive to body motion. But when they treated 3-day-old SCN2A mice – early childhood in humans – their eye reflexes were completely normal.

“These first results, using this reflex as our proxy for autism, point to an early window for future therapies that get the developing brain back on track,” Wang said.

It’s too early to say whether such an approach might someday be used to directly treat autism. But the eye reflex test, on its own, could clear the way to more expedient autism diagnosis for kids today, saving families from long diagnostic odysseys.

“If this sort of assessment works in our hands, with kids with profound, nonverbal autism, there really is hope it could be more widely adopted,” Bender said.

Source: University of California – San Francisco

Categories : PaediatricsTags :

Study Finds Screen Time for Toddlers is a Bad Idea

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Babies and toddlers exposed to television or video viewing may be more likely to exhibit atypical sensory behaviours, such as being disengaged and disinterested in activities, seeking more intense stimulation in an environment, or being overwhelmed by sensations like loud sounds or bright lights, according to data from researchers at Drexel’s College of Medicine published in the journal JAMA Pediatrics.

According to the researchers, children exposed to greater TV viewing by their second birthday were more likely to develop atypical sensory processing behaviours, such as “sensation seeking” and “sensation avoiding,” as well as “low registration” – being less sensitive or slower to respond to stimuli, such as their name being called, by 33 months old.

Sensory processing skills reflect the body’s ability to respond efficiently and appropriately to information and stimuli received by its sensory systems, such as what the toddler hears, sees, touches, and tastes.

The team pulled 2011-2014 data on television or DVD-watching by babies and toddlers at 12- 18- and 24-months from the National Children’s Study of 1471 children (50% male) nationwide.

Sensory processing outcomes were assessed at 33 months using the Infant/Toddler Sensory Profile (ITSP), a questionnaire completed by parents/caregivers, designed to give insights on how children process what they see, hear and smell, etc.

ITSP subscales examine children’s patterns of low registration, sensation seeking, such as excessively touching or smelling objects; sensory sensitivity, such as being overly upset or irritated by lights and noise; and sensation avoiding – actively trying to control their environment to avoid things like having their teeth brushed. Children score in “typical,” “high” or “low” groups based on how often they display various sensory-related behaviours. Scores were considered “typical” if they were within one standard deviation from the average of the ITSP norm.

Measurements of screen exposure at 12-months were based on caregiver responses to the question: “Does your child watch TV and/or DVDs? (yes/no),” and at 18- and 24- months based on the question: “Over the past 30 days, on average, how many hours per day did your child watch TV and/or DVDs?”

The findings suggest:

  • At 12 months, any screen exposure compared to no screen viewing was associated with a 105% greater likelihood of exhibiting “high” sensory behaviours instead of “typical” sensory behaviours related to low registration at 33 months
  • At 18 months, each additional hour of daily screen time was associated with 23% increased odds of exhibiting “high” sensory behaviours related to later sensation avoiding and low registration.
  • At 24 months, each additional hour of daily screen time was associated with a 20% increased odds of “high” sensation seeking, sensory sensitivity, and sensation avoiding at 33 months.

The researchers adjusted for age, whether the child was born prematurely, caregiver education, race/ethnicity and other factors, such as how often the child engages in play or walks with the caregiver.

The findings add to a growing list of concerning health and developmental outcomes linked to screen time in infants and toddlers, including language delay, autism spectrum disorder, behavioural issues, sleep struggles, attention problems and problem-solving delays.

“This association could have important implications for attention deficit hyperactivity disorder and autism, as atypical sensory processing is much more prevalent in these populations,” said lead author Karen Heffler, MD, an associate professor of Psychiatry in Drexel’s College of Medicine. “Repetitive behaviour, such as that seen in autism spectrum disorder, is highly correlated with atypical sensory processing. Future work may determine whether early life screen time could fuel the sensory brain hyperconnectivity seen in autism spectrum disorders, such as heightened brain responses to sensory stimulation.”

Atypical sensory processing in kids with autism spectrum disorder (ASD) and ADHD manifests in a range of detrimental behaviours. In children with ASD, greater sensation seeking or sensation avoiding, heightened sensory sensitivity and low registration have been associated with irritability, hyperactivity, eating and sleeping struggles, as well as social problems. In kids with ADHD, atypical sensory processing is linked to trouble with executive function, anxiety and lower quality of life.

“Considering this link between high screen time and a growing list of developmental and behavioural problems, it may be beneficial for toddlers exhibiting these symptoms to undergo a period of screen time reduction, along with sensory processing practices delivered by occupational therapists,” said Heffler.

The American Academy of Pediatrics (AAP) discourages screen time for babies under 18–24 months. Live video chat is considered by the AAP to be okay, as there may be benefit from the interaction that takes place. AAP recommends time limitations on digital media use for children ages two to five years to typically no more than one hour per day.

“Parent training and education are key to minimising, or hopefully even avoiding, screen time in children younger than two years,” said senior author David Bennett, PhD, a professor of Psychiatry in Drexel’s College of Medicine.

Source: Drexel’s College of Medicine

Categories : Genetics NeurologyTags :

CRISPR Untangles the Connections between Genome Organisation and Autism

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Using CRISPR gene editing, stem cells and human neurons, researchers have isolated the impact of a gene that is commonly mutated in autism. This new study, published today in The American Journal of Human Genetics, ties mutations in the gene CHD8 with a broad spectrum of molecular and cellular defects in human cortical neurons.

Autism is a highly heritable disorder with a recent increase in incidence – approximately 1 in 40 children in the US are diagnosed with autism. Over the past decade, sequencing studies have found many genes associated with autism but it has been challenging to understand how mutations in certain genes drive complex changes in brain activity and function.

The team, led by researchers at the New York Genome Center and New York University (NYU) and the Broad Institute, team developed an integrated approach to understand how mutations in the CHD8 gene alter genome regulation, gene expression, neuron function, and are tied to other key genes that play a role in autism. 

For more than a decade, it has been known that individuals with mutations in the CHD8 gene tend to have many similar ailments, such as autism, an abnormally large head size, digestive issues and difficulty sleeping. The CHD8 gene is a regulator of proteins called chromatin that surround the DNA but it is unclear how this particular gene might relate to major alterations in neural development and, in turn, result in autism. 

The research team identified numerous changes in physical state of DNA, which makes the genome more accessible to regulators of gene expression, and, in turn, drives aberrant expression of hundreds of genes. These molecular defects resulted in clear functional changes in neurons that carry the CHD8 mutation. These neurons are much less talkative: They are activated less often and send fewer messages across their synapses. 

The study authors initially observed these changes using human cortical neurons differentiated from stem cells where CRISPR was used to insert a CHD8 mutation. These findings were further bolstered by similar reductions in neuron and synapse activity when examining neurons from mice with a CHD8 mutation. These substantial defects in neuron function were circumvented when extra CHD8 was added to the cell using a gene therapy approach. In this case, extra copies of a healthy CHD8 gene without any mutation were added using a viral vector. Upon differentiation, the team found that the neurons rescued by the treatment returned to a normal rate of activity and synaptic communication, indicating that this gene therapy approach may be sufficient to restore function.

Lastly, when examining disrupted genes, the authors found that the CHD8 mutation seemed to specifically alter other genes that have been implicated in autism or intellectual disability, but not genes associated with unrelated disorders like cardiovascular disease. This suggest that CHD8 might influence selectively those genes that tend to be involved in neurodevelopmental disorders, providing an explanation for some of the particular characteristics of individuals carrying a CHD8 mutation.

Source: EurekAlert!

Categories : Neurology PaediatricsTags :

Children with Autism Have Memory Impairments, Study Finds

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Children with autism have memory challenges that hinder not only their memory for faces but also their ability to remember other kinds of information, according to new research. These impairments are reflected in distinct connection patterns children’s brains, the study found.

Published in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, the study findings clarify a debate about memory function in children with autism, showing that their memory struggles surpass their ability to form social memories. The finding should prompt broader thinking about autism in children and about treatment of the developmental disorder, according to the scientists who conducted the study.

“Many high-functioning kids with autism go to mainstream schools and receive the same instruction as other kids,” said lead author Jin Liu, PhD at Stanford University. Memory is a key predictor of academic success, said Liu, adding that memory challenges may academically disadvantage children with autism.

The study’s findings also raise a philosophical debate about the neural origins of autism, the researchers said. Social challenges are recognised as a core feature of autism, but it’s possible that memory impairments might significantly contribute to the ability to engage socially.

“Social cognition can not occur without reliable memory,” said senior author Vinod Menon, PhD.

“Social behaviours are complex, and they involve multiple brain processes, including associating faces and voices to particular contexts, which require robust episodic memory,” Menon said. “Impairments in forming these associative memory traces could form one of the foundational elements in autism.”

Comprehensive memory tests

Affecting about one in every 36 children, autism is characterised by social impairments and restricted, repetitive behaviours. The condition exists on a wide spectrum, with those on one end having severe intellectual disability and about a third of people with autism have intellectual impairments. On the other end of the spectrum, many people with high-functioning autism have normal or high IQ, complete higher education and work in a variety of fields.

Children with autism are known to have difficulty remembering faces. Some small studies have also suggested that children with autism have broader memory difficulties. They included children with wide ranges of age and IQ, both of which influence memory.

To clarify the impact of autism on memory, the new study included 25 children with high-functioning autism and normal IQ who were 8 to 12 years old, and a control group of 29 typically developing children with similar ages and IQs.

All participants completed a comprehensive evaluation of their memory skills, including their ability to remember faces; written material; and non-social photographs, or photos without any people. The scientists tested participants’ ability to accurately recognise information (identifying whether they had seen an image or heard a word before) and recall it (describing or reproducing details of information they had seen or heard before). The researchers tested participants’ memory after delays of varying lengths. All participants also received fMRI scans of their brains to evaluate how memory-associated regions are connected to each other.

Distinct brain networks drive memory challenges

In line with prior research, children with autism had more difficulty remembering faces than typically developing children, the study found.

The research showed they also struggled to recall non-social information. On tests about sentences they read and non-social photos they viewed, their scores for immediate and delayed verbal recall, immediate visual recall and delayed verbal recognition were lower.

“We thought that behavioural differences might be weak because the study participants with autism had fairly high IQ, comparable to typically developing participants, but we still observed very obvious general memory impairments in this group,” Liu said.

Among typically developing children, memory skills were consistent: If a child had good memory for faces, he or she was also good at remembering non-social information.

This wasn’t the case in autism. “Among children with autism, some kids seem to have both impairments and some have more severe impairment in one area of memory or the other,” Liu said.  

“It was a surprising finding that these two dimensions of memory are both dysfunctional, in ways that seem to be unrelated – and that maps onto our analysis of the brain circuitry,” Menon said.

The brain scans showed that, among the children with autism, distinct brain networks drive different types of memory difficulty.

For children with autism, the ability to retain non-social memories was predicted by connections in a network centred on the hippocampus. But face memory was predicted by a separate set of connections centred on the posterior cingulate cortex, a key region of the brain’s default mode network, which has roles in social cognition and distinguishing oneself from other people.

“The findings suggest that general and face-memory challenges have two underlying sources in the brain which contribute to a broader profile of memory impairments in autism,” Menon said.

In both networks, the brains of children with autism showed over-connected circuits relative to typically developing children. Over-connectivity, likely from insufficient selective pruning of neural circuits, has been found in other studies of brain networks in children with autism.

New autism therapies should account for the breadth of memory difficulties the research uncovered, as well as how these challenges affect social skills, Menon said. “This is important for functioning in the real world and for academic settings.”

Source: Stanford University Medical Center

Categories : NeurologyTags :

New Analysis Strengthens Evidence Linking Autism and the Microbiome

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In spite of burgeoning studies, the biological roots of autism remain elusive. Microbial approaches however have shown some promise, and now a study published in Nature Neuroscience has uncovered a microbial signature associated with autism, which clearly overlaps with metabolic pathways.

The study re-analysed of dozens of previously published datasets and found that they align with a recent, long-term study of autistic individuals that used a microbiome-focused intervention. These findings also underscore the importance of longitudinal studies in elucidating the interplay between the microbiome and complex conditions such as autism.

“We were able to harmonise seemingly disparate data from different studies and find a common language with which to unite them. With this, we were able to identify a microbial signature that distinguishes autistic from neurotypical individuals across many studies,” says Jamie Morton, one of the study’s corresponding authors. “But the bigger point is that going forward, we need robust long-term studies that look at as many datasets as possible and understand how they change when there is a [therapeutic] intervention.”

With 43 authors, this study brought together leaders in computational biology, engineering, medicine, autism and the microbiome who hailed from institutions in North America, South America, Europe and Asia. “The sheer number of fields and areas of expertise in this large-scale collaboration is noteworthy and necessary to get a new and consistent picture of autism,” says Rob Knight, the director of the Center for Microbiome Innovation at the University of California San Diego and a study co-author.

Autism is inherently complex, and studies that attempt to pinpoint specific gut microbes involved in the condition have been confounded by this complexity. First, autism presents in heterogeneous ways – autistic individuals differ from each other genetically, physiologically and behaviourally. Second, the microbiome presents unique difficulties. Microbiome studies typically report simply the relative proportions of specific microbes, requiring sophisticated statistics to understand which microbial population changes are relevant to a condition of interest.

This makes it challenging to find the signal amongst the noise. Making matters more complicated, most studies to date have been one-time snapshots of the microbial populations present in autistic individuals. “A single time point is only so powerful; it could be very different tomorrow or next week,” says study co-author Brittany Needham, assistant professor of anatomy, cell biology and physiology at the Indiana University School of Medicine.

“We wanted to address the constantly evolving question of how the microbiome is associated with autism, and thought, ‘let’s go back to existing datasets and see how much information we may be able to get out of them,'” says co-corresponding author Gaspar Taroncher-Oldenburg, director of Therapeutics Alliances at New York University, who initiated the work with Morton while he was a consultant-in-residence for SFARI.

In the new study, the research team developed an algorithm to re-analyse 25 previously published datasets containing microbiome and other “omic” information, such as gene expression, immune system response and diet, from both autistic and neurotypical cohorts. Within each dataset, the algorithm found the best matched pairs of autistic and neurotypical individuals in terms of age and sex, two factors that can typically confound autism studies.

Novel computational methodologies

“Rather than comparing average cohort results within studies, we treated each pair as a single data point, and thus were able to simultaneously analyse over 600 ASD-control pairs corresponding to a de facto cohort of over 1200 children,” says Taroncher-Oldenburg. “From a technical standpoint, this required the development of novel computational methodologies altogether,” he adds. Their new computational approach enabled them to reliably identify microbes that have differing abundances between ASD and neurotypical individuals.

The analysis identified autism-specific metabolic pathways associated with particular human gut microbes. Importantly, these pathways were also seen elsewhere in autistic individuals, from their brain-associated gene expression profiles to their diets. “We hadn’t seen this kind of clear overlap between gut microbial and human metabolic pathways in autism before,” says Morton.

Even more striking was an overlap between microbes associated with autism, and those identified in a recent long-term faecal microbiota transplant study led by James Adams and Rosa Krajmalnik-Brown at Arizona State University. “Another set of eyes looked at this, from a different lens, and they validated our findings,” says Krajmalnik-Brown, who was not involved in this study.

“What’s significant about this work is not only the identification of major signatures, but also the computational analysis that identified the need for future studies to include longitudinal, carefully designed measurements and controls to enable robust interpretation,” says Kelsey Martin, executive vice president of SFARI and the Simons Foundation Neuroscience Collaborations, who was not involved in the study.

“Going forward, we need more long-term studies that involve interventions, so we can get at cause-and-effect,” says Morton. Taroncher-Oldenburg, who cites the compliance issues often faced by traditional long-term studies, suggests that study designs could more effectively take into account the realities of long-term microbiome sampling of autistic individuals. “Practical, clinical restrictions must inform the statistics, and that will inform the study design,” he says. Further, he points out that long-term studies can reveal insights about both the group and the individual, as well as how that individual responds to specific interventions over time.

Importantly, researchers say these findings go beyond autism. The approach set forth here could also be employed across other areas of biomedicine that have long proved challenging. “Before this, we had smoke indicating the microbiome was involved in autism, and now we have fire. We can apply this approach to many other areas, from depression to Parkinson’s to cancer, where we think the microbiome plays a role, but where we don’t yet know exactly what the role is,” says Knight.

Source: EurekAlert!

Categories : Diseases, Syndromes and Conditions Injury & TraumaTags :

Autistic Adults Have Higher Risks of Injury and Disease

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A large-scale registry study found that older autistic adults have a significantly higher risk of injury, especially self-inflicted, and physical conditions such as type 2 diabetes, anaemia, heart failure and COPD. The findings were published in The Lancet Healthy Longevity.

“We found an increased disease burden in middle-aged and older autistic adults, both men and women, irrespective of the presence of intellectual disability,” says Shengxin Liu, doctoral student at Karolinska Institutet. “Our findings point up the need to improve the support and care of older autistic adults.”

In the population-based study, the KI researchers linked different national registers and compared the risk for five types of injury and 39 age-related physical conditions in people over the age of 45. Of the four million-plus people born between 1932 and 1967, 1930 women and 3361 men had an autism diagnosis. For each physical condition, they evaluated the 25-year cumulative incidence and the relative risk in autistic people compared with non-autistic people of the same sex and age.

Seven-fold risk of self-harm

Autistic people had a higher risk of four of five studied injures, for which self-harm accounted for the greatest risk increase, followed by poisoning, falls and other physical injuries.

“The risk of self-harm was worryingly high, a full seven times higher than in non-autistic people,” says Liu. “Reasons behind this remain largely unknown. One possible contributing factor could be mental health conditions that commonly co-occur with autism, such as anxiety and depression.”

The researchers also found a risk increase for 15 physical conditions. For example, autistic people had three times the risk of anaemia and glucose dysregulation and almost double the risk of heart failure, type 2 diabetes, and COPD (chronic obstructive pulmonary disease).

Multiple contributory factors

“We now need to find out the cause of these associations and how they are affected by factors such as biology, age when diagnosed with autism, psychotropic treatment and psychosocial environment,” says the study’s last author Mark Taylor, senior researcher at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet. “But most importantly, researchers, health services and policymakers need to cooperate to make sure that older autistic adults have a better quality of life.”

Since this was an observational study, no causal relationships can be ascertained, and the researchers were not able to take into account variables such as socioeconomic status. Furthermore, given that the study used Swedish registers, it is difficult to make generalisations to other countries.

Source: Karolinska Institutet

Categories : Metabolic Disorders PaediatricsTags :

Autism in Children Linked to Diabetes, Dyslipidaemia

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Studies have shown that children with autism spectrum disorder (ASD) have an increased risk of obesity. In turn, obesity has been linked to increased risks for diabetes, dyslipidaemia and other cardiometabolic disorders. However, the question of whether or not there is an association between autism, cardiometabolic disorders and obesity remains largely unanswered.

To help provide an insight into the possible link between ASD and cardiometabolic diseases, Texas Tech University researchers conducted a systematic review and meta-analysis. Their findings were published in JAMA Pediatrics.

In this latest meta-analysis, the researchers evaluated 34 studies that included 276 173 participants who were diagnosed with ASD and 7 733 306 who were not. The results indicated that ASD was associated with greater risks of developing diabetes overall, including both type 1 and type 2 diabetes.

The meta-analysis also determined that autism is associated with increased risks of dyslipidaemia and heart disease, though there was no significant increased risk of hypertension and stroke associated with autism. However, meta-regression analyses revealed that children with autism were at a greater associated risk of developing diabetes and hypertension when compared with adults.

Study leader Chanaka N. Kahathuduwa, MD, PhD, said the overall results demonstrate the associated increased risk of cardiometabolic diseases in ASD patients, which should prompt clinicians to more closely monitor these patients for potential contributors, including signs of cardiometabolic disease and their complications.

“We have established the associations between autism and obesity, as well as autism and cardiometabolic disease, including diabetes and dyslipidaemia,” Kahathuduwa said. “We don’t have data to support a conclusion that autism is causing these metabolic derangements, but since we know that a child with autism is more likely to develop these metabolic complications and derangements down the road, I believe physicians should evaluate children with autism more vigilantly and maybe start screening them earlier than the usual.”

Kahathuduwa also believes the study shows that physicians should think twice before prescribing medications such as olanzapine that are well known to have metabolic adverse effects to children with autism.

“Our findings should also be an eye opener for patients with autism and parents of kids with autism to simply be mindful about the higher risk of developing obesity and metabolic complications,” Kahathuduwa added. “Then they can talk with their physicians about strategies to prevent obesity and metabolic disease.”

Kahathuduwa said the next logical step for the collaborative team would be to generate evidence that either supports or rejects causality with regard to the observed associations.

Source: Texas Tech University Health Sciences Center

Categories : Neurology PaediatricsTags :

Difficulty Picking up Audio-video Timing Mismatch a Predictor of Autism in Kids

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Typically developing infants perceive audio-video synchrony better than high-risk for autism infants, according to new research published in the European Journal of Pediatrics. The research from Rutgers University might enable far earlier autism diagnoses.

If follow-up research demonstrates that most infants who miss unmatched audio and video develop autism spectrum disorder (ASD), physicians may be able to diagnose the condition years earlier – a potentially important step as early treatment strongly predicts better outcomes.

“We’re a long way from validating this as a diagnostic tool, but the results definitely suggest it could be a diagnostic tool,” said senior author Michael Lewis, professor at Rutgers Robert Wood Johnson Medical School.

Lewis and other researchers have long known children with ASD struggle to perceive audio-visual speech as a unified event, and they’ve hypothesised that this difficulty may contribute to social impairments and language deficits in such children.

To study whether these difficulties arise before it’s currently possible to diagnose ASD, generally around age 3, the researchers assembled two groups of infants ages 4 to 24 months, one comprising children whose developmental delays indicate an elevated risk of ASD and the other comprising typically developing children.

The researchers showed that participants from both groups two types of videos with progressively longer time separation between image and sound. The first videos featured a ball making noises as it bounced against a wall. The second showed a woman talking.

When watching videos of the ball, the two groups performed similarly. When watching videos of the woman, however, the differences were stark. Typically, developing children perceive audio-visual gaps that are, on average, a tenth of a second smaller than those perceived by the kids with developmental delays.

Although this result confirmed the researchers’ initial hypothesis, some findings were surprising. The ability to perceive audio-visual mismatch wasn’t associated with vocabulary size in children old enough to have a vocabulary.

If a high percentage of the children who were slowest to identify mismatched audio and video go on to be diagnosed with autism – and the findings are repeated with far more children than the 88 who participated in this study – audio-visual tests might prove a revolutionary diagnostic tool for a condition that’s becoming far more common, Lewis said.

However, scientific validation is just the first step to adoption, he said. Insurers would need to pay for tests, and paediatricians would need to embrace them before they could be used to begin providing support services to children in need.

“Earlier diagnosis won’t allow us to cure ASD anytime soon, but it will allow for the earlier provision of support services that can help such children in areas of weakness and direct them toward areas of strength,” Lewis said. “The goal is to create happy people whose schooling and, eventually, careers are well suited to them, and that’s certainly an achievable goal for most.”

Source: Rutgers University

Categories : PaediatricsTags :

A Quantifiable Model to Explain the Development of Autism

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An explanatory model presented in a thesis from University of Gothenburg may make simplify the understanding of autism development. It provides new insights into how various risk factors give rise to autism and why there is such great variability between individuals.

Autism, a neurodevelopmental condition, affects how people perceive the world around them and how they interact and communicate with others. Among individuals with autism, there are major differences in terms of personal traits and manifestations alike. The disorder is therefore usually described as a spectrum, with numerous subtle variations.

While theoretical, the new explanatory model is also practical in application, since its various components are quantifiable through testing. The model describes various contributing factors and how they combine to prompt an autism diagnosis and cause other neurodevelopmental conditions.

Three contributing factors

The model links three contributing factors. Together, these result in a pattern of behaviour that meets the criteria for an autism diagnosis:

  1. Autistic personality – hereditary common genetic variants that give rise to an autistic personality.
  2. Cognitive compensation – intelligence and executive functions, such as the capacity to learn, understand others, and adapt to social interactions.
  3. Exposure to risk factors – for example, harmful genetic variants, infections, and other random events during gestation and early childhood that adversely affect cognitive ability.

“The autistic personality is associated with both strengths and difficulties in cognition but does not, as such, mean that diagnostic criteria are fulfilled. Still, exposure to risk factors that inhibit people’s cognitive ability may affect their capacity to tackle difficulties, which contributes to individuals being diagnosed with autism,” says Darko Sarovic, physician and postdoctoral researcher at Sahlgrenska Academy, University of Gothenburg, who wrote the thesis.

The model makes it clear that it is the many different risk factors combined that bring about the major differences among individuals on the spectrum. The various components of the model are supported by results from previous research.

Adaptive ability

High executive functioning skills may let people cover up their impairment, reducing their risk of meeting the diagnostic criteria for autism. This may explain why a lower degree of intelligence is observed among people diagnosed with autism, as well as other neurodevelopmental conditions. It also affords an understanding of why intellectual disability is more common among these groups. Thus, the model indicates that low cognitive ability is not part of the autistic personality but, rather, a risk factor that leads to diagnostic criteria being met.

“The autistic personality is associated with various strengths. For example, parents of children with autism are overrepresented among engineers and mathematicians. The parents themselves have probably been able to compensate for their own autistic personality traits and thus not met the criteria for an autism diagnosis. The impact of the disorder has then become more noticeable in their children owing, for instance, to an exposure to risk factors and relatively low cognitive ability,” Sarovic says.

Gender differences affect diagnosis

The diagnosis of autism is more common among boys than girls, and girls often get their diagnosis later in life. Some girls reach adulthood before being diagnosed, after many years of diffuse personal difficulties.

“Girls’ symptoms are often less evident to other people. It’s well known that girls generally have more advanced social skills, which probably means that they’re better at compensating for their own difficulties. Girls also tend to have fewer autistic traits and be less susceptible to the effects of risk factors. Accordingly, the model can help to answer questions about the gender gap,” Sarovic says.

Research and diagnostics

The model also proposes ways of estimating and measuring the three factors, enabling use of the model in research studies. Diagnostics is another conceivable area of ​​use. In a pilot study in which 24 participants had been diagnosed with autism and 22 controls had not, measuring the three factors of the model enabled more than 93% to be correctly assigned to the right category. The model can also be used to explain the inception of other neurodevelopmental disorders, such as schizophrenia.

Source: University of Gothenburg

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Hyperbaric Therapy Reduces Neuroinflammation in Autism

On By ModernMedia
Depiction of a human brain
Image by Fakurian Design on Unsplash

A new study at Tel Aviv University showed significant improvements in social skills and the condition of the autistic brain through hyperbaric therapy. The study which is reported in the journal International Journal of Molecular Sciences, was conducted on lab models of autism.

Hyperbaric medicine, where patients sit in special high-pressure chambers while breathing pure oxygen, is considered safe and, besides treating decompression sickness in divers, is already in use for other conditions. The use of hyperbaric medicine to treat autism is contentious, with many holding that it is based on pseudoscience. In recent years, scientific evidence has been accumulating that unique protocols of hyperbaric treatments improve the supply of blood and oxygen to the brain, thereby improving brain function.

Changes observed in the brain included a reduction in neuroinflammation, which is known to be associated with autism. A significant improvement was also found in the social functioning of the animal models treated in the pressure chamber. The study’s success has many implications regarding the applicability and understanding of treating autism using pressure chamber therapy.

The breakthrough was led by doctoral student Inbar Fischer, from the laboratory of Dr Boaz Barak of Tel Aviv University.

Improved brain function

“The medical causes of autism are numerous and varied, and ultimately create the diverse autistic spectrum with which we are familiar,” explains Dr Barak. “About 20% of autistic cases today are explained by genetic causes, that is, those involving genetic defects, but not necessarily ones that are inherited from the parents. Despite the variety of sources of autism, the entire spectrum of behavioural problems associated with it are still included under the single broad heading of ‘autism,’ and the treatments and medications offered do not necessarily correspond directly to the reason why the autism developed.”

In the preliminary phase of the study, a girl carrying the mutation in the SHANK3 gene, which is known to lead to autism, received treatments in the pressure chamber, conducted by Prof Shai Efrati. After the treatments, it was evident that the girl’s social abilities and brain function had improved considerably.

In the next stage, and in order to comprehend the success of the treatment more deeply, the team of researchers at Dr Barak’s laboratory sought to understand what being in a pressurised chamber does to the brain. To this end, the researchers used lab models carrying the same genetic mutation in the SHANK3 gene as that carried by the girl who had been treated. The experiment comprised a protocol of 40 one-hour treatments in a pressure chamber over several weeks.

“We discovered that treatment in the oxygen-enriched pressure chamber reduces inflammation in the brain and leads to an increase in the expression of substances responsible for improving blood and oxygen supply to the brain, and therefore brain function,” explains Dr Barak. “In addition, we saw a decrease in the number of microglial cells, immune system cells that indicate inflammation, which is associated with autism.”

Increased social interest

“Beyond the neurological findings we discovered, what interested us more than anything was to see whether these improvements in the brain also led to an improvement in social behaviour, which is known to be impaired in autistic individuals,” adds Dr Barak. “To our surprise, the findings showed a significant improvement in the social behaviour of the animal models of autism that underwent treatment in the pressure chamber compared to those in the control group, who were exposed to air at normal pressure, and without oxygen enrichment. The animal models that underwent treatment displayed increased social interest, preferring to spend more time in the company of new animals to which they were exposed in comparison to the animal models from the control group.”

Inbar Fischer concludes, “the mutation in the animal models is identical to the mutation that exists in humans. Therefore, our research is likely to have clinical implications for improving the pathological condition of autism resulting from this genetic mutation, and likely also of autism stemming from other causes. Because the pressure chamber treatment is non-intrusive and has been found to be safe, our findings are encouraging and demonstrate that this treatment may improve these behavioral and neurological aspects in humans as well, in addition to offering a scientific explanation of how they occur in the brain.”

Source: Tel Aviv University