Diagnosis of Asperger Syndrome - Differences From High-functioning Autism

Differences From High-functioning Autism

The distinction between Asperger's and other ASD forms is to some extent an artifact of how autism was discovered. Although individuals with Asperger's tend to perform better cognitively than those with autism, the extent of the overlap between Asperger's and high-functioning autism is unclear. Overall, relatively few differences are reported between Asperger's and autism on parameters related to causation. A standard assumption is that Asperger's and autism have a common cause, and are variable expressions of the same underlying disorder. A 2008 review of classification studies found that results largely did not support differences between the diagnoses, and that the most salient group characteristics came from IQ characterizations. The current ASD classification may not reflect the true nature of the conditions. A panel session at a 2008 diagnosis-related autism research planning conference noted problems with the classification of AS as a distinct subgroup of ASD, and two of three breakout groups recommended eliminating AS as a separate diagnosis.

A neuropsychological profile has been proposed for AS; if verified, it could differentiate between AS and HFA and aid in differential diagnosis. Relative to HFA, people with AS have deficits in nonverbal skills such as visual-spatial problem solving and visual-motor coordination, along with stronger verbal abilities. Several studies have found AS with a neuropsychologic profile of assets and deficits consistent with a nonverbal learning disability, but several other studies have failed to replicate this. The literature review did not reveal consistent findings of "nonverbal weaknesses or increased spatial or motor problems relative to individuals with HFA", leading some researchers to argue that increased cognitive ability is evidenced in AS relative to HFA regardless of differences in verbal and nonverbal ability.