Imaging Test Designed for Autism Spectrum Disorder

Typically, diagnosis—an unquantifiable process based on clinical judgment—is time-consuming and tiresome on children and their families. That may change with this new diagnostic test.

This imaging modality, while not ready to be used as the clinical standard of care, offers huge 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 (Roanoke, VA, USA) 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, slated for online publication in January 2015 in the journal Clinical Psychological Science, revealed that the perspective-tracking response can be used to determine whether someone has autism spectrum disorder. The path to this discovery has been a long, iterative one. In a 2006 study by Prof. Montague and others, pairs of subjects had their brains scanned using functional magnetic resonance imaging (fMRI), 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 Prof. 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 recognition led the scientists to investigate how the middle cingulate cortex response differs in individuals at different developmental levels. In a 2008 study, Prof. Montague and his colleagues asked athletes to watch a brief clip of a physical action, such as kicking a ball or dancing, while undergoing fMRI.

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,” Prof. 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 discovered that in participants with autism spectrum disorder, the more passive the response is, the more severe the symptoms. Montague and his team theorized that a clear biomarker for self-perspective exists and that they could track it using functional MRI. They also conjectured that the biomarker could be used as an application in the clinical diagnosis of people with autism spectrum disorder.

In 2012, the scientists designed another examine to see whether they could elicit a brain response to help them compute the indefinable. 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, the study participants were shown 15 images of themselves and 15 images of a child correlated for age and gender for four seconds per image in a random order. Similar to the control adults, the control children had a high response in the middle cingulate cortex when viewing their own images. By contrast, children with autism spectrum disorder had a significantly diminished response. Most notably, the investigators could detect this difference in individuals using only a single image.

The researchers realized they had developed a single-stimulus functional MRI diagnostic technique. The single-stimulus part is important, Prof. Montague emphasized, as it enables speed. Children with autism spectrum disorder cannot stay in the scanner for long, so the test must be fast. “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,” Prof. 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 disparities through brain scans, scientists are adding a critical component to the typical process of neuropsychiatric diagnosis: math. Prof. Montague has been a pioneering figure in this field, which he termed computational psychiatry. The idea is that scientists can tie the function of mental disorders to the disrupted processes of neural tissue through mathematic approaches. Clinicians then can use measurable data for earlier diagnosis and treatment.

An earlier diagnosis can also have a great impact on the children and their families, Prof. Montague said. “The younger children are at the time of diagnosis,” he concluded, “the more they can benefit from a range of therapies that can transform their lives.”

Related Links:
Virginia Tech Carilion Research Institute