Autism Discussion Page: Low/High Functioning Autism

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Low/High Functioning vs. Severe/Mild Autism

The last post discussed the problem with labeling someone high vs. low functioning in regards to their diagnosis. The problem comes from the fact that a person can be high functioning (verbal, good academic skills, fair to good personal care), but have moderate to severe autism (rigid inflexible thinking, strong sensory issues, poor emotional regulation, delayed processing, and impaired ability to relate with others). Also, a person can be considered low functioning (poor verbal skills, limited academic skills, and minimal personal care skills) but only have mild autism (more flexibility, calmer emotionally, less sensory sensitivities, and more socially connected).

This appears contradictory at first, but when we look closer can we see that these labels actually represent two different dimensions. The first, level of functioning dimension, represents the degree of cognitive functioning or intellectual disability. The second dimension represents the severity of autism symptoms. You could look at these two dimensions as crisscrossing on perpendicular planes, with the dimension of intellectual abilities (high, moderate, low) running vertically and the dimension of autism symptoms (severe, moderate, and mild) running horizontally. The moderate levels of each dimension meeting at the intersection of the two dimensions. Consequently, you can have people who are very high functioning verbally and intellectually, and be moderately to severely impaired in autism symptoms. This can be confusing for many people who initially see the very bright, verbal child, and not initially see the severity of the autism. Or, assume that the nonverbal child is severely autistic. It is not that easy to diagnosis.

Making matters even more complicated, is the variability of verbal skills. Although verbal skills are highly correlated with intelligence, it is not always the case. Do not assume that the child who is nonverbal has poor intellectual abilities. There are some children who find it difficult to talk due to auditory processing and motor planning difficulties, not lack of cognitive skills. People often assume that the nonverbal child is severely impaired and place lower expectations on them. The same is also true for the children who are very verbal, but most speech is hidden in scripting and echolalia. They may appear to have higher cognitive abilities then they actually may have. Even for the two basic dimensions (intelligence and autism symptoms), the mixing in of verbal abilities can be deceiving.

The use of labels like high and low functioning, and severely and mildly impaired, are not diagnostic terms, but used more as descriptors when people try and categorize level of impairments. Hopefully the diagnostic criterion in the new DSM will be more descriptive and accurate. Until then, and probably for some time, people will be adding their own descriptive labels to the diagnoses.

This series on “labels, diagnoses, and co-occurring disorders” can be found in the green book, “Autism Discussion Page on Anxiety, Behavior, School and Parenting Strategies.”

To me the terms high and low functioning are only useful to represent the extent to which anyone can actualise or not actualise their own potential, innate talents and aptitudes.

And this is not static and fixed - for example, a "high functioning" person with aspergers can have periods of low functioning - when those talents et al can't be transformed into actualisation; and a "low functioning" ASD person can have periods of high functioning - producing an extraordinary work of art for example.

I dislike labels that are so inflexible that they try to lock people into rigid definitions of low capability or high capability, and while capability levels do differ - we are all born with different patterns of innate talents - this "boxing up" is a hierarchy which is not very helpful in terms of growing innate potentials.

HFA doesn't mean anything to me beyond autism without intellectual disability.