Autism and sensory disorders affect different parts of the brain

A study shows that autism and sensory disorders affect distinctly different parts of a child's brain.

Although the vast majority of kids with autism have abnormal sensory behaviors, their brains are still wired very differently from children who have trouble processing sensory stimuli, researchers report.

Children with sensory processing disorders (SPD) can be overly sensitive to sound, sight and touch. They can also have poor motor skills and show a lack of concentration.

Complicating matters, some kids with SPD have more severe symptoms than others. Some have trouble tolerating loud noises, like a vacuum. Others can't hold a pencil or control their emotions. Symptoms can also vary from one day to the next. This had led to a debate about whether SPD should be considered a separate disorder, the researchers pointed out.

These kids "often don't get supportive services at school or in the community because SPD is not yet a recognized condition," study corresponding author Dr. Elysa Marco, a cognitive and behavioral child neurologist at Benioff Children's Hospital San Francisco at the University of California, San Francisco (UCSF), said in a university news release. "We are starting to catch up with what parents already knew; sensory challenges are real and can be measured both in the lab and the real world."

"With more than 1 percent of children in the United States diagnosed with an autism spectrum disorder, and reports of 5 to 16 percent of children having sensory processing difficulties, it's essential we define the neural underpinnings of these conditions, and identify the areas they overlap and where they are very distinct," study senior author Dr. Pratik Mukherjee, a professor of radiology and biomedical imaging and bioengineering at UCSF, said in a university news release.

In conducting the study, published online July 30 in the journal PLOS ONE, the researchers compared the brains of 16 boys with SPD and 15 boys with autism. All of the boys were between the ages of 8 and 12. These patients were compared to 23 boys who were developing normally.

Using an advanced form of MRI, the researchers were able to examine white matter, the "wiring" that links different areas of the brain.

The boys with SPD and autism had reduced connectivity in certain areas of the brain involved in basic sensory information. However, only the boys with autism had impairment in specific parts of the brain essential for social-emotional processing.

"One of the classic features of autism is decreased eye-to-eye gaze, and the decreased ability to read facial emotions," noted Marco. "The impairment in this specific brain connectivity not only differentiates the autism group from the SPD group but reflects the difficulties patients with autism have in the real world. In our work, the more these regions are disconnected, the more challenge they are having with social skills."

Meanwhile, children with SPD had less connectivity in the tracts of the brain involved in sensory processing.

"One of the most striking new findings is that the children with SPD show even greater brain disconnection than the kids with a full autism diagnosis in some sensory-based tracts," noted Marco. "If we can start by measuring a child's brain connectivity and seeing how it is playing out in a child's functional ability, we can then use that measure as a metric for success in our interventions and see if the connectivities are changing based on our clinical interventions."

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One stop shop for a scholarly review of state-of-the-art research on autism in children

This article reviews the recent research that has been done on autism in 6 main areas.

Recent years have seen exciting progress in key areas of research on autism spectrum disorders (ASD): from possible genetic causes, to effective treatments for common symptoms and clinical problems, to promoting success for young people with ASD entering college. Updates on these and other advances in ASD research are presented in the March special issue of Harvard Review of Psychiatry.

"Autism is one of the most challenging disorders to treat and the public health concerns associated with the disorder are numerous due to its burden on the individual, on the family and on society," write guest editors Drs Jean A. Frazier of University of Massachusetts Medical School and Christopher J. McDougle of Harvard Medical School. The special issue provides a timely update on research into the causes, important clinical issues, and evidence-based treatments for ASD.

Updates on ASD Research in Six Key Areas

Leading experts provide state-of-the-art reviews on six topics: the genetics of ASD; the use of psychoactive drugs; symptoms of special clinical problems, including obesity, gastrointestinal problems, and sensory issues; and transitioning to college.

Genetics. Over the last few years, there have been "unprecedented advances" in understanding the genetic causes of ASD. Hundreds of genes conferring varying degrees of ASD risk have been identified to date. Many of these genes also appear to be risk factors for related neurodevelopmental disorders and psychiatric problems. While many unanswered questions remain, it may soon be possible to make specific genetic diagnoses in children with ASD.

Psychoactive medications. Despite limited evidence, psychotropic drugs are widely used to manage behavior problems and mental health disorders in children with ASD. For medication classes -- including antidepressants and stimulants -- effectiveness may differ for youth versus adults with ASD. New treatments affecting specific neurotransmitters and the hormone oxytocin are under development, and may help in targeting the "core symptoms" of ASD.

Obesity. Obesity is a common problem with a major impact on the health of children with ASD. Some ASD-related genes may also promote obesity; the same is true for antipsychotic drugs used to help manage behavior problems. Other contributing factors may include sleep disorders and barriers to getting enough exercise. Childhood obesity and related health issues may be a "significant threat" to the health and quality of life of children with ASD.

Gastrointestinal issues. Children with ASD also have high rates of gastrointestinal symptoms and disorders. Some genes linked to ASD may also play a role in gastrointestinal disturbances, with a possible link to immune system dysfunction. There's also emerging evidence of a potential "gut-brain" connection, with gastrointestinal dysfunction contributing to the development or severity of ASD symptoms.

Sensory symptoms. Children with ASD have various abnormalities of sensory function, including both over- and under-responsivity as well as "sensory seeking behavior." Although the neurobiology of these sensory symptoms remains unclear, some researchers suggest they are related to known abnormalities of brain structure and function. Recent studies show that sensory symptoms are related to other ASD-related symptoms and behaviors; more research is needed to demonstrate the effectiveness of "sensory integration therapy" and other occupational therapy approaches.

Preparing for college. The final article highlights the need for new approaches to meeting the needs of "high-functioning" ASD patients entering college. Students "on the spectrum" transitioning to college are at risk of both academic and social problems, and may benefit from accommodation and supports. Based on a growing body of research, a set of recommendations for developing more effective transition plans for children with ASD are proposed.

Along with the editors of Harvard Review of Psychiatry, Drs Frazier and McDougal hope their special issue will provide a useful update for clinicians caring for the growing numbers of individuals and families living with ASD. They conclude, "Clearly, more research is needed on every level for the field to help support and treat individuals on the spectrum so that they can optimize their developmental trajectory and as adults become integral members of our work force."

The journal can be found online at:http://journals.lww.com/hrpjournal/Pages/default.aspx

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Mixing of the senses is more common in autistic children

A condition known as synaesthesia where the senses are mixed was found to be more common in children with autism.

People with autism are more likely to also have synaesthesia, suggests new research in the journal Molecular Autism.

Synaesthesia involves people experiencing a 'mixing of the senses', for example, seeing colours when they hear sounds, or reporting that musical notes evoke different tastes. Autism is diagnosed when a person struggles with social relationships and communication, and shows unusually narrow interests and resistance to change. The team of scientists from Cambridge University found that whereas synaesthesia only occurred in 7.2% of typical individuals, it occurred in 18.9% of people with autism.

On the face of it, this is an unlikely result, as autism and synaesthesia seem as if they should not share anything. But at the level of the brain, synaesthesia involves atypical connections between brain areas that are not usually wired together (so that a sensation in one channel automatically triggers a perception in another). Autism has also been postulated to involve over-connectivity of neurons (so that the person over-focuses on small details but struggles to keep track of the big picture).

The scientists tested -- and confirmed -- the prediction that if both autism and synaesthesia involve neural over-connectivity, then synaesthesia might be disproportionately common in autism.

The team, led by Professor Simon Baron-Cohen at the Autism Research Centre at Cambridge University, tested 164 adults with an autism spectrum condition and 97 adults without autism. All volunteers were screened for synaesthesia. Among the 31 people with autism who also had synaesthesia, the most common forms of the latter were 'grapheme-colour' (18 of them reported black and white letters being seen as coloured) and 'sound-colour' (21 of them reported a sound triggering a visual experience of colour). Another 18 of them reported either tastes, pains, or smells triggering a visual experience of colour.

Professor Baron-Cohen said: "I have studied both autism and synaesthesia for over 25 years and I had assumed that one had nothing to do with the other. These findings will re-focus research to examine common factors that drive brain development in these traditionally very separate conditions. An example is the mechanism 'apoptosis,' the natural pruning that occurs in early development, where we are programmed to lose many of our infant neural connections. In both autism and synaesthesia apoptosis may not occur at the same rate, so that these connections are retained beyond infancy."

Professor Simon Fisher, a member of the team, and Director of the Language and Genetics Department at Nijmegen's Max Planck Institute, added: "Genes play a substantial role in autism and scientists have begun to pinpoint some of the individual genes involved. Synaesthesia is also thought to be strongly genetic, but the specific genes underlying this are still unknown. This new research gives us an exciting new lead, encouraging us to search for genes which are shared between these two conditions, and which might play a role in how the brain forms or loses neural connections."

Donielle Johnson, who carried out the study as part of her Master's degree in Cambridge, said: "People with autism report high levels of sensory hyper-sensitivity. This new study goes one step further in identifying synaesthesia as a sensory issue that has been overlooked in this population. This has major implications for educators and clinicians designing autism-friendly learning environments."

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Children with sensory disorders overwhelmed with new school year

This article discusses how children with sensory processing disorders can be overwhelmed with the changes from a new school year.

Transitioning from summer to a new school year is hard for any kid, but it is particularly difficult for children who have trouble processing new sensations, according to an expert on what is known as "sensory processing disorder."

Sensory processing disorder is a neurological problem that affects behavior and learning. For kids with this disorder, too much sensory overload or the wrong kind of stimulation can lead to problems with attention, coordination and impulsiveness as the child tries to either increase or decrease the sensations they are experiencing.

Varleisha Gibbs, an assistant professor of occupational therapy at University of the Sciences in Philadelphia, explained that the transition back to school disrupts the daily routines that these children have established during the summer. She noted, however, planning ahead can help ease the stress of this transition.

"Students with sensory processing disorders typically struggle with adapting to change," Gibbs said in a university news release. "A new school year brings an abundance of changes, including new teachers and classmates, schedules and routines, classrooms and settings, as well as new demands and expectations in the classroom."

To ease the transition to a new school year for children with sensory processing disorders, Gibbs recommended that children, teachers and parents or caregivers take the following steps:

• Plan a visit. Before the first day of class, arrange a visit to the school to familiarize the child with the school setting and the teacher. If possible, take photos of the surroundings to help the child acclimate to the environment ahead of time.
• Be proactive. Reach out to the school early to inform administrators about the child's therapy schedule. A child's private occupational therapy sessions should be coordinated with any therapy offered at school so they do not overlap.
• Pack a sensory kit. Certain fidget devices may help keep children calm and focused during a stressful transition time. These objects include stress balls, seat cushions, gum and music with headphones. Teachers can also provide a variety of seating options in the classrooms, including beanbag chairs and therapy balls.
• Be open. Because not all children with sensory processing disorders are placed in special education, communicating a child's needs to teachers and school administrators can help ensure they are able to benefit from their calming strategies. For example, these children may need to chew gum in class or listen to headphones between classes.
• Shop early. Purchase backpacks and school clothes well in advance so children can try them on and identify any items that are bothersome or uncomfortable. Be sure to remove all tags, wash the clothes and find underwear that can alleviate any irritability from the fabric rubbing against the skin.
• Set an example. When parents are calm and collected, it's easier for children to feel the same way about going back to school.

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Study: Children with autism better at spotting motion

A study shows that children with autism are better at spotting movement than children without autism. This could explain some of the symptoms of autism.

Children with autism see simple movement twice as quickly as other children their age, a new study shows.

Researchers say this hypersensitivity to motion may provide clues to a fundamental cause of the developmental disorder.

Such heightened sensory perception in autism may help explain why some people with the disorder are painfully sensitive to noise and bright lights. It also may be linked to some of the complex social and behavioral deficits associated with autism.

“We think of autism as a social disorder because children with this condition often struggle with social interactions, but what we sometimes neglect is that almost everything we know about the world comes from our senses,” says Duje Tadin, assistant professor of brain and cognitive sciences at the University of Rochester. “Abnormalities in how a person sees or hears can have a profound effect on social communication.”

Although previous studies have found that people with autism possess enhanced visual abilities with static images, this is the first research to discover a heightened perception of motion.

For the study published in the Journal of Neuroscience, 20 children with autism and 26 typically developing children, ages 8 to 17, looked at brief video clips of moving black and white bars and simply indicated which direction the bars were heading, right or left.

Each time a participant made the correct direction choice, the next video clip became slightly shorter and thus a little more difficult. When they made a mistake, the next video became a bit longer and thus easier to see. In this way, the researchers were able to measure how quickly children with autism can perceive motion.

When the bars in the image were just barely visible, both groups of children performed identically. When the contrast or darkness of the bars was increased all participants in the study got better at perceiving the direction of movement.

“But kids with autism, got much, much better—performing twice as well as their peers,” says co-lead author Jennifer Foss-Feig, a postdoctoral fellow at the Child Study Center at Yale University. In fact, the worst performing participant with autism was roughly equal to the average of the participants without autism.

Sensory overload

“This dramatically enhanced ability to perceive motion is a hint that the brains of individuals with autism keep responding more and more as intensity increases. Although this could be considered advantageous, in most circumstances if the neural response doesn’t stop at the right level it could lead to sensory overload,” explains Foss-Feig.

Such hypersensitive perception is the neural signature for a brain that is unable to dampen its response to sensory information. This same increase in neural “excitability” is also found in epilepsy, which is strongly linked to autism. In fact, as many as one third of individuals with autism also have epilepsy. Normally, the brain puts the brakes on its responses to sound, taste, touch, and other stimuli when they become too intense.

What’s important about this dampening ability is that it’s a ubiquitous mechanism controlling how humans perceive the world, researchers say.

“If the processing of our vision, hearing, and other sensory systems is abnormal in some way, it will have a cascading effect on other brain functions,” says Carissa Cascio, assistant professor of psychiatry at Vanderbilt University, in whose lab the study was conducted.

“You may be able to see better, but at some point the brain really is over responding. A strong response to high intensity stimuli in autism could be one reason for withdrawal.”

The research builds on earlier findings that people with autism process visual stimuli differently. For example, previous studies have shown that individuals with autism are better able to perceive basic patterns, are able to see simple line images more quickly, and are more focused on details than individuals without the condition.

By contrast, in more complex tasks, like facial recognition, these enhancements become impairments. Likewise, autism is associated with deficits in perceiving motion patterns more complex than the simple moving bars used in this study, such as detecting walking and other biological movements.

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