Asperger’s: Out of DSM but Still in the Brain?

The DSM-5 may have done away with the diagnosis of Asperger’s syndrome—as distinct from autism—but the conversation (fracas is often a better word) over how to and whether we should differentiate low- and high-functioning autism continues. The latest item to address this thorny issue is a study out of Boston Children’s Hospital that aimed to uncover physical brain differences between Asperger’s children and children with the wider autism spectrum disorder diagnosis using electroencephalography, or EEG. The results are…mixed.

Lead researcher Frank Duffy had already, in a previous study, determined that EEG could differentiate pretty well between kids with autism diagnoses and a typically developing control group. He did this by attaching those familiar EEG electrodes to their scalps and recording the electrical impulses the brain uses to communicate with itself. This paints a picture of connectivity between brain regions—and allows researchers to differentiate between stronger or weaker connections. Using some sophisticated data analysis tools, they were able to show that most kids with autism have similar differences in connectivity when compared to the control group. That is, properly interpreted EEG data agreed with clinical diagnosis.

Now, to the current study: Let’s say that Duffy’s earlier work showed EEG could reliably differentiate between apples (kids with autism spectrum disorders) and oranges (typically developing kids). The new study reaches two conclusions that fall neatly on either side of the Asperger’s debate. First, in the new study Duffy distinguished three groups of kids: those with Asperger’s, those with autism, and those who were typically developing. Duffy found that, physiologically, Asperger’s and other forms of autism are much more like each other than they are like the control group. Apples were still grouped with apples, oranges with oranges.

But! Duffy’s second discovery is that if you compare kids with Asperger’s and other kids on the autism spectrum, EEG can reliably differentiate them based on brain connectivity. There are brain differences that support the (now passé) clinical separation between Asperger’s and autism. So the study shows that Asperger’s is on the autism spectrum, but also distinct—they’re both still apples, but Asperger’s is a Red Delicious and autism is Granny Smith.

I detect in Duffy’s paper where his affections lie, and it isn’t a far-fetched position for anyone who has experience with the incredibly wide range of the autism spectrum. “Although the findings above in many ways agree with the DSM-5 placement of [Asperger’s disorder] within the broad autistic spectrum,” the study authors write, “they also demonstrate that patients with Asperger’s can be physiologically distinguished from those with ASD. Recognition of Asperger’s as a separate entity is important from the patients’ perspectives of obtaining appropriate medical and educational services as well as of establishing a personal identity.”

In other words, though the diagnosis has changed, the kids are the same, and need the same personalized supports. This is true whether a child has limited communication and self-injurious behaviors or is highly verbal, intelligent, and socially awkward to the point of impairment. The results of this study could lead to new tools for diagnosis, prognosis, and monitoring of treatment efficacy. But in the meantime, it helps to remember what I’ve been told by every experienced autism clinician I have spoken with. “You’ve seen one child with autism,” the saying goes, “and you’ve seen one child with autism.”