autism spectrum disorders, part deux

Another instance where the question begs to be asked: are handwriting patterns differentiated between autistic and Asperger children?

This study found quality of letter formation in the handwriting of children with ASD to be lower than in normally developing children.  The subject hasn't really been addressed since 2001, when Beversdorf et al identified the significant instance of macrographia in patients with ASD, as compared to age- and IQ-matched control subjects.  Both studies have subsumed autism and Asperger into the ASD umbrella -- just as likely for the purposes of procuring a larger test subject sample as for making their results widely applicable:

"Whereas all subjects with autism spectrum disorder met the diagnostic criteria for autism through their reported behavior during childhood, most subjects had demonstrated significant improvement in function over time, such that the distinction between the various forms of autism spectrum disorder was not as clear. Therefore the more general term autism spectrum disorder is used to describe these patients." (Beversdorf)

The original description of Asperger syndrome in 1944 noted difficulties in motor coordination, specifically in handwriting (Frith; translated 1991).  One year before, Leo Kanner published his first paper asserting that some autistic children were quite agile, performing "hair-raising feats of balancing," while others were clumsy "despite dextrous manipulation of objects" (Frith pg. 95). 

I would love to see a study comparing the different aspects of handwriting using both the Revised Physical and Neurological Examination for Subtle Sign (from the Kennedy Krieger Institute study), and the Autism Spectrum Quotient and Empathy Quotient tests used by Baron-Cohen's group to differentiate autism and Asperger syndrome.  Any cerebellar distinctions between autism and Asperger could be very illuminating...

autism spectrum disorders and dsm-v politics

An article in the New York Times this morning by Simon Baron-Cohen addressed the debate in the DSM committee over subsuming the conditions of Autism and Aspergers in the fifth edition of the "psychiatric bible"(promised in 2012).  The committee is deliberating whether or not to eliminate Asperger from the diagnostic manual and characterize its discrete symptoms as a degree of autism in the spectrum (perhaps "intermediate functioning autism").

Autism and Asperger syndrome are both characterized by impaired communication skills, a desire for keenly focused stimuli and strong inclination toward repetition. They are distinguished only by a slower onset of language skills and latency of intelligence in autism, says Baron-Cohen.  He further suggests that this distinction is proving not to be concrete enough, and that the DSM-V committee's struggle with the controversy can be attributed to the lack of physiological distinction of these psychiatric conditions.

I would agree with Baron-Cohen that there is not currently enough genetic distinction between autism and Asperger syndrome to warrant their being entirely separate conditions outside the spectrum disorders umbrella in the DSM-V.  However, I think that defining Asperger syndrome idiosyncratically is important to preserve in the new manual.  Here is why:   

1)  Baron-Cohen mentions his own group's recent identification of 14 Asperger-specific genes,19 genes specific to autism and 7 shared (Chakrabarti et al 2009).  They measured 68 candidate genes in two experiments: the first measured autistic traits in an undiagnosed sample population using the Autism Spectrum Quotient; the second, using the Empathy Quotient.  These two experiments were designed to identify autistic and Asperger cases among the sample:

"We searched for common genetic variants (single nucleotide polymorphisms (SNPs)) on the assumption that autistic traits are continuously distributed in the general population [Constantino & Todd, 2005; Sung et al., 2005]."

"In Experiment 1, autistic traits (measured on AQ and/or EQ) were nominally associated at P<0.05 with SNPs from 19 genes. In Experiment 2, SNPs from 14 genes were nominally associated at P<0.05 with AS."

Six genes were nominally significant in both experiments. This study alone suggests that Asperger syndrome deserves a distinction as a sub-group in the Autism Spectrum Disorders (ASD) category that the DSM-V committee is considering, as opposed to eliminating it entirely, as is also being considered.

The Charkrabarti study is impressive, and the first step in the important attempt to identify the genetic and epigenetic correlates of autism and Asperger separately.  However, there is still an extensive amount of correlative research to be done.  A good amount of this is ongoing through the AutDB Project.

2)  If for no other reason than to preserve the honor of the venerable Hans Asperger.

3)  To keep company the solitary other recognized ASD, Pervasive Developmental Disorder - Not Otherwise Specified (PDD-NOS).*  Perhaps these could both become sub-groups in the ASD category.

It is noteworthy that a great deal of genetic research already refer to their studies as ASD interactions/links/correlations (PubMed or Google Scholar this).  I am terribly eager to find out whether or not this plays a strong role in the decision of the DSM-V committee.


*High- and Low-functioning autism are not classified as spectrum disorder subgroups, although they should be... and perhaps, one day, will be, provided there is a physiological distinction to be drawn between them, Asperger and PDD-NOS.