What is high functioning autism, and how does it differ from Asperger syndrome? This is a tricky question, and not one that this article is likely to answer definitively. First, there is no formal diagnosis called “high functioning autism.” What’s more, there’s no agreed upon definition of “high functioning.” As a result, while the term “high functioning autism” is often tossed around, it is a hard definition to pin down.
Generally speaking, doctors prefer to group people with autistic symptoms into discrete diagnostic categories. Rett syndrome and Fragile X syndrome are relatively clear cut disorders, and thus are likely to be correctly diagnosed. Classic autism is also fairly clear cut: Children with classic autism are usually non-verbal, unengaged, and unable to perform well on standard diagnostic tests.
But then there are the people who are high functioning but also demonstrate clearly autistic behaviors. For example, depending upon their age, they can use meaningful language, read, write, do math, show affection, complete daily tasks but can’t hold eye contact, maintain a conversation, engage in play, pick up on social cues, etc. What is the correct diagnosis for such a child? Is it Pervasive Developmental Not Otherwise Specified” (PDD-NOS)? Asperger syndrome? High functioning autism?
PDD-NOS is a catch-all diagnosis. Often understood to mean the same thing as “high functioning autistic,” it really incorporates individuals at all function levels whose symptoms don’t fully correlate with classic autism. So a PDD-NOS diagnosis may provide some information to parents and teachers but cannot guide treatment.
Asperger syndrome is a much more specific diagnosis, with specific diagnostic criteria. Until recently, the biggest difference between Asperger syndrome and high functioning autism was based on whether a person developed speech typically as a toddler. Those who did develop speech typically were considered to have Asperger syndrome while those who did not (even if they developed typical speech later) were diagnosed with autism. Now, experts are wondering whether speech development is the best way to distinguish between autism and Asperger syndrome or if there even is a difference.
High functioning autism is not an official diagnostic term, though it may be used as such. It tends to describe people who have many or all of the symptoms of autism but did not develop language typically. It’s a helpful diagnosis that can help guide appropriate treatment and school placement. On the other hand, it is important to be sure that a “real” diagnosis (that is, one that is described in the official diagnostic manual) is also placed in your records. It is this “real” diagnosis which may pave the way to medical and Social Security benefits down the road.
One useful explanation of the difference between Asperger syndrome and high functioning autism comes from the National Autism Society in the UK. Here’s what it says:
Both people with HFA and AS are affected by the triad of impairments common to all people with autism.
Both groups are likely to be of average or above average intelligence.
The debate as to whether we need two diagnostic terms is ongoing. However, there may be features such as age of onset and motor skill deficits which differentiate the two conditions
Although it is frustrating to be given a diagnosis which has yet to be clearly defined it is worth remembering that the fundamental presentation of the two conditions is largely the same. This means that treatments, therapies and educational approaches should also be largely similar. At the same time, all people with autism or Asperger syndrome are unique and have their own special skills and abilities. These deserve as much recognition as the areas they have difficulty in.