Imaging test for autism spectrum disorder

autism spectrum disorder

autism spectrum disorder

Virginia Tech Carilion Research Institute scientists have developed a brain-imaging technique that may be able to identify children with autism spectrum disorder in just two minutes.

This test, while far from being used as the clinical standard of care, offers promising diagnostic potential once it undergoes more research and evaluation.

“Our brains have a perspective-tracking response that monitors, for example, whether it’s your turn or my turn,” said Read Montague, the Virginia Tech Carilion Research Institute professor who led the study.

“This response is removed from our emotional input, so it makes a great quantitative marker,” he said. “We can use it to measure differences between people with and without autism spectrum disorder.”

The finding, expected to be published online next week in Clinical Psychological Science, demonstrates that the perspective-tracking response can be used to determine whether someone has autism spectrum disorder.

Usually, diagnosis – an unquantifiable process based on clinical judgment – is time consuming and trying on children and their families. That may change with this new diagnostic test.

The path to this discovery has been a long, iterative one. In a 2006 study by Montague and others, pairs of subjects had their brains scanned using functional magnetic resonance imaging, or MRI, as they played a game requiring them to take turns.

From those images, researchers found that the middle cingulate cortex became more active when it was the subject’s turn.

“A response in that part of the brain is not an emotional response, and we found that intriguing,” said Montague, who also directs the Computational Psychiatry Unit at the Virginia Tech Carilion Research Institute and is a professor of physics at Virginia Tech. “We realized the middle cingulate cortex is responsible for distinguishing between self and others, and that’s how it was able to keep track of whose turn it was.”

That realization led the scientists to investigate how the middle cingulate cortex response differs in individuals at different developmental levels. In a 2008 study, Montague and his colleagues asked athletes to watch a brief clip of a physical action, such as kicking a ball or dancing, while undergoing functional MRI.

The athletes were then asked either to replay the clips in their mind, like watching a movie, or to imagine themselves as participants in the clips.

“The athletes had the same responses as the game participants from our earlier study,” Montague said. “The middle cingulate cortex was active when they imagined themselves dancing – in other words, when they needed to recognize themselves in the action.”

In the 2008 study, the researchers also found that in subjects with autism spectrum disorder, the more subdued the response, the more severe the symptoms.

Montague and his team hypothesized that a clear biomarker for self-perspective exists and that they could track it using functional MRI. They also speculated that the biomarker could be used as a tool in the clinical diagnosis of people with autism spectrum disorder.

In 2012, the scientists designed another study to see whether they could elicit a brain response to help them compute the unquantifiable. And they could: By presenting self-images while scanning the brains of adults, they elicited the self-perspective response they had previously observed in social interaction games.

In the current study, with children, subjects were shown 15 images of themselves and 15 images of a child matched for age and gender for four seconds per image in a random order.

Like the control adults, the control children had a high response in the middle cingulate cortex when viewing their own pictures. In contrast, children with autism spectrum disorder had a significantly diminished response.

Importantly, Montague’s team could detect this difference in individuals using only a single image.

Montague and his group realized they had developed a single-stimulus functional MRI diagnostic technique. The single-stimulus part is important, Montague points out, as it enables speed. Children with autism spectrum disorder cannot stay in the scanner for long, so the test must be quick.

“We went from a slow, average depiction of brain activity in a cognitive challenge to a quick test that is significantly easier for children to do than spend hours under observation,” Montague said. “The single-stimulus functional MRI could also open the door to developing MRI-based applications for screening of other cognitive disorders.”

By mapping psychological differences through brain scans, scientists are adding a critical component to the typical process of neuropsychiatric diagnosis – math.

Montague has been a pioneering figure in this field, which he coined computational psychiatry. The idea is that scientists can link the function of mental disorders to the disrupted mechanisms of neural tissue through mathematical approaches. Doctors then can use measurable data for earlier diagnosis and treatment.

An earlier diagnosis can also have a tremendous impact on the children and their families, Montague said.

“The younger children are at the time of diagnosis,” Montague said, “the more they can benefit from a range of therapies that can transform their lives.”

Asperger’s syndrome dropped from DSM

Asperger’s syndrome dropped from psychiatrists’ handbook the DSM:

 

Gary McKinnon, the British hacker who is diagnosed with Asperger's syndrome. The condition is to be removed from American psychiatric handbook the DSM and its symptoms covered by autism spectrum disorder.

Gary McKinnon, the British hacker who is diagnosed with Asperger’s syndrome. The condition is to be removed from American psychiatric handbook the DSM and its symptoms covered by autism spectrum disorder.

 

Asperger’s syndrome is to be dropped from the psychiatrists’ Diagnostic and Statistical Manual (DSM) of Mental Disorders, the American publication that is one of the most influential references for the profession around the world. The term “Asperger’s disorder” will not appear in the DSM-5, the latest revision of the manual, and instead its symptoms will come under the newly added “autism spectrum disorder”, which is already used widely. That umbrella diagnosis will include children with severe autism, who often do not talk or interact, as well as those with milder forms. The British hacker Gary McKinnon is diagnosed with Asperger’s and it contributed to a government decision not to extradite him from Britain to the US on cybercrime charges. The DSM is used in a number of countries to varying degrees. Psychiatrists in some countries including Britain use the International Classification of Diseases (ICD) published by the World Health Organisation or a combination of both handbooks. In other changes to the DSM, abnormally bad and frequent temper tantrums will be diagnosed as DMDD, meaning disruptive mood dysregulation disorder. Supporters say it will address concerns about too many children being misdiagnosed with bipolar disorder and treated with powerful psychiatric drugs. The term “gender identity disorder”, for children and adults who strongly believe they were born the wrong gender, is being replaced with “gender dysphoria” to remove the stigma attached to the word “disorder”. Supporters equated the change with removing homosexuality as a mental illness in the diagnostic manual decades ago. The revisions come in the first major rewrite in nearly 20 years of the diagnostic guide used by psychiatrists in the US and other countries. The changes were approved on Saturday. Full details of all the revisions will come in May 2013 when the American Psychiatric Association’s new diagnostic manual is published. The changes will affect the diagnosis and treatment of millions of children and adults worldwide, as well as medical insurance and special education services. The aim was not to expand the number of people diagnosed with mental illness but to ensure those affected were more accurately diagnosed so they could get the most appropriate treatment, said Dr David Kupfer, the University of Pittsburgh psychiatry professor who chaired the revision committee. One of the most hotly argued changes was how to define the various ranges of autism. Some on the panel opposed the idea of dropping the specific diagnosis for Asperger’s. People with that disorder often have high intelligence and vast knowledge on narrow subjects but lack social skills. Some Asperger’s families opposed any change, fearing their children will lose a diagnosis and no longer be eligible for special services, but experts have said this will not be the case. People with dyslexia also were closely watching for the update. Many with the reading disorder did not want their diagnosis dropped, and it will not be. Instead, the new manual will have a broader learning disorder category to cover several conditions including dyslexia, which causes difficulty understanding letters and recognising written words. The shorthand name for the new edition, the organisation’s fifth revision of the Diagnostic and Statistical Manual, is DSM-5. Group leaders say specifics will not be disclosed until the manual is published but they confirmed some changes. A 2000 edition of the manual made minor changes but the last major edition was published in 1994.