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19 January 2010

Autism News

As the father of a child who has been diagnosed with an Autism Spectrum Disorder, I tend to keep my eye on scientific literature reagrding the subject. And by scientific literature, I mean actual science, not hare-brained ideas like "mommy sense" or whatever else type of bullshit the likes of Jenny McCarthy and those idiots peddle (which can be decidedly harmful). One of my favorite sites to go to is ScienceDaily. They even have a whole section dedicated to Autism.

So why make a blog entry on this? Well, mostly because I haven't blogged in a while! I have been very busy with numerous things that consume more time than the day offers, and blogging was one of those extra things that just had to be prioritized out. Im sure you know how that goes.

Anyway, I haven't been over to ScienceDaily lately, so I was excited to find out more about the ability to diagnose autism. Sadly, autism is a difficult dissorder to properly and truly diagnose, and it takes quite a while. Which of course leads to the whole confusion and confirmation bias with the vaccine canard. (Just as an aside, I am a dad of an autistic child, and we all vaccinate!) Anyway, here is the article that I found:

Brain Imaging May Help Diagnose Autism

ScienceDaily (Jan. 10, 2010) — Children with autism spectrum disorders (ASDs) process sound and language a fraction of a second slower than children without ASDs, and measuring magnetic signals that mark this delay may become a standardized way to diagnose autism.

Researchers at The Children's Hospital of Philadelphia report their findings in an online article in the journal Autism Research, published January 8.

"More work needs to be done before this can become a standard tool, but this pattern of delayed brain response may be refined into the first imaging biomarker for autism," said study leader Timothy P.L. Roberts, Ph.D., vice chair of Radiology Research at Children's Hospital.

ASDs are a group of childhood neurodevelopmental disorders that cause impairments in verbal communication, social interaction and behavior. ASDs are currently estimated to affect as many as one percent of U.S. children, according to a recent CDC report.

Like many neurodevelopmental disorders, in the absence of objective biological measurements, psychologists and other caregivers rely on clinical judgments such as observations of behavior to diagnose ASDs, often not until a child reaches school age. If researchers can develop imaging results into standardized diagnostic tests, they may be able to diagnose ASDs as early as infancy, permitting possible earlier intervention with treatments. They also may be able to differentiate types of ASDs (classic autism, Asperger's syndrome or other types) in individual patients.

In the current study, Roberts and colleagues used magnetoencephalography (MEG), which detects magnetic fields in the brain, similar to the way electroencephalography (EEG) detects electrical fields. Using a helmet that surrounds the child's head, the team presents a series of recorded beeps, vowels and sentences. As the child's brain responds to each sound, noninvasive detectors in the MEG machine analyze the brain's changing magnetic fields.

The researchers compared 25 children with ASDs, having a mean age of 10 years, to 17 age-matched typically developing children. The children with ASDs had an average delay of 11 milliseconds (about 1/100 of a second) in their brain responses to sounds, compared to the control children. Among the group with ASDs, the delays were similar, whether or not the children had language impairments.

"This delayed response suggests that the auditory system may be slower to develop and mature in children with ASDs," said Roberts. An 11-millisecond delay is brief, but it means, for instance, that a child with ASD, on hearing the word 'elephant' is still processing the 'el' sound while other children have moved on. The delays may cascade as a conversation progresses, and the child may lag behind typically developing peers."

A 2009 study by Roberts and colleagues sheds light on how changes in brain anatomy may account for the delays in sound processing. The study team used MEG to analyze the development of white matter in the brains of 26 typically developing children and adolescents. Because white matter carries electrical signals in the brain, signaling speed improves when neurons are better protected with an insulating sheath of a membrane material called myelin.

In this previous study, the researchers showed that normal age-related development of greater myelination corresponds with faster auditory responses in the brain. "The delayed auditory response that we find in children with ASDs may reflect delayed white matter development in these children," said Roberts. Roberts says his team's further studies will seek to refine their imaging techniques to determine that their biomarker is specific to ASDs, and will investigate other MEG patterns found in children with ASDs in addition to auditory delays.

Grants from National Institute of Health, the Nancy Lurie Marks Family Foundation, Autism Speaks, and the Pennsylvania Department of Health supported this research. In addition, Roberts holds an endowed chair, the Oberkircher Family Chair in Pediatric Radiology at The Children's Hospital of Philadelphia. Roberts' co-authors were from Children's Hospital, including the Hospital's Center for Autism Research.

And to further debunk the anti-vax pro-disease nutters:

More Evidence That Autism Is a Brain 'Connectivity' Disorder

ScienceDaily (Jan. 11, 2010) — Studying a rare disorder known as tuberous sclerosis complex (TSC), researchers at Children's Hospital Boston add to a growing body of evidence suggesting that autism spectrum disorders, which affect 25 to 50 percent of TSC patients, result from a miswiring of connections in the developing brain, leading to improper information flow. The finding may also help explain why many people with TSC have seizures and intellectual disabilities.

Findings were published online in Nature Neuroscience on January 10.

TSC causes benign tumors throughout the body, including the brain. But patients with TSC may have autism, epilepsy or intellectual disabilities even in the absence of these growths. Now, researchers led by Mustafa Sahin, MD, PhD, of Children's Department of Neurology, provide evidence that mutations in one of the TSC's causative genes, known as TSC2, prevent growing nerve fibers (axons) from finding their proper destinations in the developing brain.

Studying a well-characterized axon route -- between the eye's retina and the visual area of the brain -- Sahin and colleagues showed that when mouse neurons were deficient in TSC2, their axons failed to land in the right places. Further investigation showed that the axons' tips, known as "growth cones," did not respond to navigation cues from a group of molecules called ephrins. "Normally ephrins cause growth cones to collapse in neurons, but in tuberous sclerosis the axons don't heed these repulsive cues, so keep growing," says Sahin, the study's senior investigator.

Additional experiments indicated that the loss of responsiveness to ephrin signals resulted from activation of a molecular pathway called mTOR, whose activity increased when neurons were deficient in TSC2. Axon tracing in the mice showed that many axons originating in the retina were not mapping to the expected part of the brain.

Although the study looked only at retinal connections to the brain, the researchers believe their findings may have general relevance for the organization of the developing brain. Scientists speculate that in autism, wiring may be abnormal in the areas of the brain involved in social cognition.

"People have started to look at autism as a developmental disconnection syndrome -- there are either too many connections or too few connections between different parts of the brain," says Sahin. "In the mouse models, we're seeing an exuberance of connections, consistent with the idea that autism may involve a sensory overload, and/or a lack of filtering of information."

Sahin hopes that the brain's miswiring can be corrected by drugs targeting the molecular pathways that cause it. The mTOR pathway is emerging as central to various kinds of axon abnormalities, and drugs inhibiting mTOR has already been approved by the FDA. For example, one mTOR inhibitor, rapamycin, is currently used mainly to prevent organ rejection in transplant patients, and Sahin plans to launch a clinical trial of a rapamycin-like drug in approximately 50 patients with TSC later this year, to see if the drug improves neurocognition, autism and seizures.

In 2008, Sahin and colleagues published related research in Genes & Development showing that when TSC1 and TSC2 are inactivated, brain cells grow more than one axon -- an abnormal configuration that exacerbates abnormal brain connectivity. The mTOR pathway was, again, shown to be involved, and when it was inhibited with rapamycin, neurons grew normally, sprouting just one axon.

Supporting the mouse data, a study by Sahin and his colleague Simon Warfield, PhD, in the Computational Radiology Laboratory at Children's, examined the brains of 10 patients with TSC, 7 of whom also had autism or developmental delay, and 6 unaffected controls. Using an advanced kind of MRI imaging called diffusion tensor imaging, they documented disorganized and structurally abnormal tracts of axons in the TSC group, particularly in the visual and social cognition areas of the brain (see image). The axons also were poorly myelinated -- their fatty coating, which helps axons conduct electrical signals, was compromised. (In other studies, done in collaboration with David Kwiatkowski at Brigham and Women's Hospital, giving rapamycin normalized myelination in mice.)

Sahin has also been studying additional genes previously found to be deleted or duplicated in patients with autism, and finding that deletion of some of them causes neurons to produce multiple axons -- an abnormality that, again, appears to be reversed with rapamycin.

"Many of the genes implicated in autism may possibly converge on a few common pathways controlling the wiring of nerve cells," says Sahin. "Rare genetic disorders like TSC are providing us with vital clues about brain mechanisms leading to autism spectrum disorders. Understanding the neurobiology of these disorders is likely to lead to new treatment options not only for TSC patients, but also for patients with other neurodevelopmental diseases caused by defective myelination and connectivity, such as autism, epilepsy and intellectual disability."

The current study was funded by grants from the National Institutes of Health, the John Merck Scholars Fund, Tuberous Sclerosis Alliance, the Manton Foundation, the Children's Hospital Boston Translational Research Program, and the Children's Hospital Boston Mental Retardation and Developmental Disabilities Research Center.

Duyu Nie was first author on the paper. Coauthors were Duyu Nie, Alessia Di Nardo, Juliette M Han, Hasani Baharanyi, Ioannis Kramvis, and ThanhThao Huynh, all of the F.M. Kirby Neurobiology Center and Department of Neurology, Children's Hospital Boston; Sandra Dabora of Brigham and Women's Hospital; Simone Codeluppi and Elena B Pasquale of the Burnham Institute for Medical Research, and University of California San Diego; and Pier Paolo Pandolfi of Beth Israel Deaconess Cancer Center.

FULL DISCLOSURE: I am also one of the administrators for the Facts, not Fantasy website. Just in case anyone was wondering. And yes, i will put this article there in the near future.

Science! It works bitches!

2 comments:

JD Curtis said...

Sorry to hear that about your child. Autism has been growing and it seems that we don't know why this is occuring.

Has mercury, insofar as innoculations, been ruled out?

What are the "common denominators" that keep popping up in the physiologies of the parents, or environmental factors, are concerned?

Yes, I would appreciate a comment de vez y cuando

Larian LeQuella said...

If you go over to http://factsnotfantasy.com/vaccines.html#Thimerosal you'll see that not only has it been ruled out, but it's also a poor argument to even consider it. :)

Right now, it seems to be very genetically linked as opposed to environmental factors. As a matter of fact, there was a correlation with linoleum floors of all things!

And as a family, since her ASD is Aspberger's, it's not particularly devastating. If anything, we all find humour in it by situations that happen from time to time. But thank you though.