Asperger's Autism and PDD-NOS. . . Is there a difference?
Yesterday I listened to a very interesting talk by Catherine Lord, one of the creators of the ADOS test. ADOS is the “gold standard” in the world of autism diagnosis, and she's a leading figure in the world of autism testing and evaluation, so I jumped at the chance to hear her thoughts on where we're headed in that regard.
People who receive an autism diagnosis are told they have one of three conditions: Autism, Asperger's, or PDD-NOS. The big question is, who should be diagnosed with what? Is there a coherent sense of classification, or is it merely arbitrary or random? She reviewed the diagnostic data for several thousand spectrumites in an effort to determine what caused a person to end up in one of those three categories.
To her surprise, after analyzing the data, she found the principal predictive factor had nothing to do with the individual. Looking at records from a number of good university hospitals, she found places who called almost everyone Asperger, and other places where everyone was PDD-NOS. There was no discernible pattern of variation between individuals; they seemed to simply get different diagnoses in different places.
Was there more to the story?
To answer that, she looked at other factors, like IQ. For example, many people call Asperger's "autism lite" or "high IQ autism.". Her review of Asperger diagnoses at one Ivy League school bore that out, with their Asperger kids having average IQ of 123. However, other doctors must see Asperger's differently, because a Midwest clinic in the study has an average Asperger IQ of 85.
She looked at quality of language in older kids and found similar ambiguity. Asperger's is supposed to distinguish autistic kids who don't have trouble speaking or understanding language. That can be true at age three, but what happens when kids get older and talk more? In the final analysis she did not find any consistent measures of the individuals themselves that led to one label or the other being applied.
In my opinion, those findings support the argument that there is no consistent standard that sets the three descriptive terms for autisms apart. A difference at one point becomes invisible at another. For example, you could say four year old Mike does not talk so he's autistic and Jimmy talks up a storm so he's Aspergers. But what happens when both kids are ten and they look and sound the same? Were the differences justified? What purpose might they serve by their difference?
Her findings made one more strong argument for combining all autism diagnoses under the heading of Autism Spectrum Disorder, with a described range of disability or affect.
That's the way things seem to be headed for the next DSM.
At the same time, Dr. Lord expressed concern that many people have a strong personal investment in one diagnostic name or the other, and they should be able to keep using the different terms.
Stay tuned for more tomorrow, from IMFAR 2011
John Elder Robison
Author of Be Different, 2011