Brain anatomy differences between autistic and typically developing individuals are indistinguishable

November 4, 2014
autism
Quinn, an autistic boy, and the line of toys he made before falling asleep. Repeatedly stacking or lining up objects is a behavior commonly associated with autism. Credit: Wikipedia.

In the largest MRI study to date, researchers from Ben-Gurion University of the Negev and Carnegie Mellon University have shown that the brain anatomy in MRI scans of people with autism above age six is mostly indistinguishable from that of typically developing individuals and, therefore, of little clinical or scientific value.

The study, "Anatomical Abnormalities in Autism?" was just published in the prestigious Oxford journal Cerebral Cortex.

"Our findings offer definitive answers regarding several scientific controversies about , which have occupied for the past 10 to 15 years," says Dr. Ilan Dinstein of BGU's Departments of Psychology and Brain and Cognitive Sciences. "Previous hypotheses suggesting that autism is associated with larger intra-cranial gray matter, white matter and amygdala volumes, or smaller cerebellar, corpus callosum and hippocampus volumes were mostly refuted by this new study."

The researchers used data from the Autism Brain Imaging Data Exchange (ABIDE), which provides an unprecedented opportunity to conduct large-scale comparisons of anatomical MRI scans across autism and control groups and resolve many outstanding questions. This recently- released database is a worldwide collection of MRI scans from over 1,000 individuals (half with autism and half controls) ages six to 35 years old.

"In the study we performed very detailed anatomical examinations of the scans, which included dividing each brain into over 180 regions of interest and assessing multiple anatomical measures such as the volume, surface area and thickness of each region," Dinstein explains.

The researchers then examined how the autism and control groups differed with respect to each region and also with respect to groups of regions using more complex analyses.

"The most striking finding here was that anatomical differences within both the control group and the autistic group was immense and greatly overshadowed minute differences between the two groups," Dinstein explains. "For example, individuals in the control group differ by 80 to 90 percent in their brain volumes, while differences in brain volume across autism and control groups differed by two to three percent at most. This led us to the conclusion that anatomical measures of brain volume or surface areas do not offer much information regarding the underlying mechanism or pathology of Autistic Spectrum Disorder (ASD)," he states.

"These sobering results suggest that autism is not a disorder that is associated with specific anatomical pathology and as a result, anatomical measures alone are likely to be of low scientific and clinical significance for identifying children, adolescents and adults with ASD, or for elucidating their neuropathology.

Dinstein believes that more complex explanations involving combinations of measures in more homogeneous sub-groups are likely to be the answer. "Expecting to find a single answer for the entire ASD population is naïve. We need to move on to thinking about how to split up this very heterogeneous group of disorders into more meaningful biologically-relevant subgroups," he says.

This conclusion stands in sharp contrast to numerous reports of significant anatomical differences described by smaller studies, which have typically included comparisons of 40 to 50 individuals. "The problem with small samples, large within-group heterogeneity, and a scientific bias to report only positive findings, is that small samples are likely to yield significant differences across autism and control groups in a few of the 180 brain regions," Dinstein explains.

"In such a situation one would expect that each study would find significant differences in different areas and that findings will be very inconsistent across studies," he says. "This is exactly what you see when you examine the anatomy literature from the last decade or so. Our study simply explains why this has been happening and puts an end to several ensuing debates."

Explore further: Presence or absence of early language delay alters anatomy of the brain in autism

Related Stories

Presence or absence of early language delay alters anatomy of the brain in autism

September 23, 2014
A new study led by researchers from the University of Cambridge has found that a common characteristic of autism – language delay in early childhood – leaves a 'signature' in the brain. The results are published today ...

Brain imaging alone cannot diagnose autism

November 2, 2012
In a column appearing in the current issue of the journal Nature, McLean Hospital biostatistician Nicholas Lange, ScD, cautions against heralding the use of brain imaging scans to diagnose autism and urges greater focus on ...

Team finds age-related changes in how autism affects the brain

March 13, 2013
Newly released findings from Bradley Hospital published in the Journal of the American Academy of Child & Adolescent Psychiatry have found that autism spectrum disorders (ASD) affect the brain activity of children and adults ...

Autism affects different parts of the brain in women and men

August 8, 2013
Autism affects different parts of the brain in females with autism than males with autism, a new study reveals. The research is published today in the journal Brain as an open-access article.

Autism in children affects not only social abilities, but also broad range of sensory and motor skills

June 25, 2013
A group of investigators from San Diego State University's Brain Development Imaging Laboratory are shedding a new light on the effects of autism on the brain.

Study finds autism-related early brain overgrowth slows by age 2 years

May 2, 2011
Scientists using magnetic resonance imaging (MRI) observed that the brains of children with autism spectrum disorder are larger than those without autism, but this difference appears related to increased rates of brain growth ...

Recommended for you

Signaling pathway may be key to why autism is more common in boys

October 17, 2017
Researchers aiming to understand why autism spectrum disorders (ASD) are more common in boys have discovered differences in a brain signaling pathway involved in reward learning and motivation that make male mice more vulnerable ...

Whole genome sequencing identifies new genetic signature for autism

October 12, 2017
Autism has genetic roots, but most cases can't be explained by current genetic tests.

Mum's immune response could trigger social deficits for kids with autism

October 10, 2017
The retrospective cohort study of 220 Australian children, conducted between 2011-2014, indicates that a "an immune-mediated subtype" of autism driven by the body's inflammatory and immunological systems may be pivotal, according ...

Largest study to date reveals gender-specific risk of autism occurrence among siblings

September 25, 2017
Having one child with autism is a well-known risk factor for having another one with the same disorder, but whether and how a sibling's gender influences this risk has remained largely unknown.

Faulty cell signaling derails cerebral cortex development, could it lead to autism?

September 20, 2017
As the embryonic brain develops, an incredibly complex cascade of cellular events occur, starting with progenitors - the originating cells that generate neurons and spur proper cortex development. If this cascade malfunctions ...

Predicting atypical development in infants at high risk for autism?

September 12, 2017
New research from the Sackler Institute for Developmental Psychobiology at Columbia University Medical Center (CUMC) identifies a potential biomarker that predicts atypical development in 1- to 2-month-old infants at high ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.