The autism spectrum may have originally been construed as one dimensional, from minor to profound autism. However, I would say now that 'spectrum' is predominately understood in the autism research community as meaning "diverse." Diverse presentations, diverse symptoms, diverse co-occurring symptoms, diverse lived experiences, diverse outcomes, a la if you've met one person with autism, you've met one person with autism.

The Autism Phenome Project is predicated on the idea that there may be some underlying homogeneity so that we might identify clinically meaningful subgroups within the autism "spectrum"/"diversity", which may help us develop better targeted interventions, support services, etc.

Great question.

I think there's a lot of history of using the term "spectrum" to mean a single dimension. See https://en.wikipedia.org/wiki/Spectrum for some examples and counterexamples.

I suspect it will create confusion to use the same word for a multi-dimensional meaning, especially when there is preexisting literature about the "autism spectrum" that used the single-dimensional meaning. I think it would be ideal to use another term.

It seems that the thing we're talking about is "a cluster of imperfectly correlated traits". Googling a bit, I see "syndrome" as one possibility (although it may carry the connotation of a disease, although that may be inevitable with autism). "Trait cluster"?

(If one wants to dig into the light metaphor: The thing you're looking at is a beam of light. You use a prism, and that splits the beam into its constituent frequencies. When you shine the light through a prism onto paper, the resulting image is a spectrum. But the original light beam itself is not a spectrum. Thus, the most appropriate way to use "spectrum" in connection with autism would be for someone to take a test that measures several different traits, and then the test results are the "spectrum". I'm not going to try to fight for that definition, though.)

Definitely. Scientific understanding, thankfully, evolves!

So in keeping with the light analogy, it's a gamut then.

No, gamut : discrete :: spectrum : continous

Since when is a gamut discrete?

I think the original meaning of gamut - the full set of musical notes in a scale – refers to a discrete series. But in color theory the gamut is the complete set of colors that can be reproduced by a device (or which is present in an image), and is continuous (although you could probably argue for discrete depending on how colors are defined in a particular model.)

It's a multi-dimensional spectrum, it can't be captured adequately by a single number.

I was not aware of this. About a decade ago I was diagnosed using a questionnaire and received a single score on a numeric scale from 0 to 35. I think the maximum score was in either the low to mid-30's, I don't recall exactly what it was. I don't remember what the assessment was called, but it was an actual standardized test given by a psychiatrist.

I haven't kept up with the current state of understanding, but now I am intrigued and I wonder how I score on those other dimensions they now asses.

It's probably because you scored high on several factors.

Instead of one score, think of it like a cumulative score. You have, let's say, 7 factors all scored from 1 to 5. If the score for being diagnosed with Autism is 21, for example, there are many ways to achieve that. Three areas with a 5 and then a single 3 in any other area would have you diagnosed. Similarly if you score 3 across the board.

Basically, they're saying when you hit that minimum overall score, your factors put you that far divergent from most people that it's at least noticeable.

Nonsense. Just uses bit flags. :)

love it.