In the article, the authors explained as background information that diagnostic instruments in the ASD field have been useful in merging samples, comparing results across studies, and defining populations. However, BEC (best-estimate clinical) diagnoses of ASDs have been the gold standard for a long time. Examples of ASDs covered include Asperger's syndrome, autistic disorder, and PDD-NOS (pervasive developmental disorder-not-otherwise specified).
Catherine Lord, Ph.D. and team set out to find out whether the relationship between clinical diagnoses and behavioral appearance of various autism spectrum disorders varied from site-to-site across the 12 universities in their observational study.
The study involved 1,814 males and 288 females who were clinically diagnosed with an ASD after two diagnostic assessments. The researchers gathered data on demography, genetic research, as well as developmental information.
The authors explained that even at these 12 sites with consistent documentation and the usage of standardized diagnostic instruments, the clinical distinctions among categorical diagnostic subtypes were not reliable.
"Although distributions of scores on standardized measures were similar across sites, significant site differences emerged in best-estimate clinical diagnoses of specific autism spectrum disorders.
Relationships between clinical diagnoses and standardized scores, particularly verbal IQ, language level, and core diagnostic features, varied across sites in weighting of information and cutoffs."
Perhaps diagnoses differences may be a reflection on regional variations, the investigators suggested.
The authors wrote:
"For example, in some regions, children with diagnoses of autistic disorder receive different services than do children with other ASD diagnoses; elsewhere, autistic disorder diagnoses may be avoided as more stigmatizing than diagnoses of PDD-NOS or Asperger's syndrome."
(conclusion) Results support the move from existing subgroupings of autism spectrum disorders to dimensional descriptions of core features of social affect and fixated, repetitive behaviors, together with characteristics such as language level and cognitive function."