Friday, February 12, 2010

What is severe autism?

ResearchBlogging.org
We have to wait, patiently, for the DSM-V people to cough up their system for ranking and classifying all autistics according autism "severity." In the meantime, some recently reported data are worth mulling over.

First, here is the most recent unofficial DSM-V autism "severity" ranking-system proposal, and here is my response, including information about instruments commonly claimed to measure autism "severity." The current official DSM-V void in this area can be located here.

An increasingly prominent measure of autism "severity" is the Social Responsiveness Scale. Developed by John Constantino, it now exists in different age-range versions. Its purpose encompasses quantifying what are presumed to be autistic traits, from none on up, across the full range of humanity.

The SRS is a 65-item questionaire most often filled out by parents or teachers, whose ratings classify children according to "severity of autistic symptomology." Higher scores, above an established threshold, indicate greater autism "severity," and are therefore considered worse.

In a recently epublished high-profile paper (Roberts et al., in press), SRS scores were reported for 25 autistic children who were recruited then divided into two groups according to performance on a popular test of language abilities.

The children were about 10 years old. Sixteen autistic children classified as non-language-impaired achieved an average language ability score of ~100, right at the mean for the administered test. In contrast, nine autistic children classified as language-impaired scored ~65, more than two standard deviations lower.

I'm going to ignore the main purpose of this interesting study, which used magnetoencephalography to compare auditory evoked responses in autistics and nonautistics. Instead I'll concentrate on how this divided sample of autistic children was characterized.

Apart from language scores, the authors reported what could be considered verbal and performance intelligence, as per indexes from the latest child version of the Wechsler scales. Here the non-language-impaired autistic children scored significantly higher, with ~20-point and ~16-point advantages, respectively, over the language-impaired autistic group.

As I wrote above, Roberts et al. (in press) also reported SRS scores, described here as "dimensional symptom severity ratings."

SRS raw scores are commonly used in research, but the SRS has also been standardized, providing T-scores which account for variables such as gender and differences between raters (e.g. parents vs teachers). T-scores are standard scores with a mean of 50 and a standard deviation of 10.

While the SRS is not yet considered a diagnostic instrument, a T-score of 60, one SD above the mean, is currently the SRS-based cut-off for an autistic spectrum diagnosis. Standard scores from 60 to 75 currently indicate SRS-based "mild to moderate" autism; 76 or higher is the SRS-based "severe" autism range.

As might be predicted, the two autistic groups in Roberts et al. (in press) differed significantly on SRS T-scores; that is, they differed on autism "severity." One group scored on average 70.89, falling into the "mild to moderate" range. The other scored 81.44, a full standard deviation higher, and crossed the threshold into "severe" autism.

As wouldn't be predicted at all, the non-language-impaired autistics, who had advantages not only in language but on measures of intelligence, were the "severe" autistics, while the language-impaired children were the "mild to moderate" ones.

My wild guess is that if an autism intervention was shown in fair tests to consistently produce a reduction in SRS scores of a full standard deviation, and what's more, transported groups--however small--of autistic children from the "severe" to the "mild to moderate" SRS range, this would be considered tremendous progress.

The sample of autistic children in Roberts et al. (in press) is of course very small, as is charateristic of the bulk of the autism literature, and much can happen within such small sample. But these data aren't inconsistent with numerous other existing reports, and deserve at least a look while we wait, patiently, for the DSM-V people to proclaim on autism "severity."

You can find an uncritical short blurb about the SRS, which used to be called the "Social Reciprocity Scale," here, and a more extensive, critical description here.

Many thanks to Jennifer Stevenson for (patiently) answering my questions about the SRS. Any factual errors are entirely mine and should you find any, you should alert me immediately.


Reference:

Roberts TP, Khan SY, Rey M, Monroe JF, Cannon K, Blaskey L, Woldoff S, Qasmieh S, Gandal M, Schmidt GL, Zarnow DM, Levy SE, & Edgar JC (2010). MEG detection of delayed auditory evoked responses in autism spectrum disorders: towards an imaging biomarker for autism. Autism research : official journal of the International Society for Autism Research PMID: 20063319


Postscript: This post has been included in the 21st edition of Scientia Pro Publica.

12 comments:

The author said...

Are you aware of the existing Axis V descriptions of severity which run accross the whole gamut of DSMIV as it is.

In other words a global funtioning rating has been there for some time.

Sujective scores or estimates of disability have existed in medicine for sometime, for instance when I visited a physiotherapist I had to rate my pain which was then given an index of disability, likewise for my tinnitus recently.

A good measure is a useful thing if it is geared to finding where problems exist in order to remediate them.

However a bad measure is one that is arbitrary and difficult to render objectively.

I suspect the severity scale will be used in political ways tied to the economics of service provision, but again what is new there.

David N. Andrews M. Ed., C. P. S. E. said...

"T-scores are standard scores with a mean of 50 and a standard deviation of 10."

Your values for mean and standard deviation are correct but the T-score is not a standard score; standard scores are similar to T-scores in that they have a mean of 10 and a standard deviation of 3; I think the word you were looking for is standardised.

Might not seem a big deal, but there is a very significant difference between standardised and standard, when talking about scores.

Michelle Dawson said...

In areas of research I'm familiar with, T-scores, Z-scores, and 100-mean-15-SD, to give just three examples, can be referred to as standard scores, while the most frequent use is to refer to 100-mean-15-SD.

Anonymous said...

Lengthy and Analytical, but Needs to be said:

Maybe its because -
(1.) I'm not "neurotypical;"
(2.) I'm not a garden variety person with Autism;
(3.) I'm not an Aspie; but instead
(4.) I'm an Autistic savant (with a law degree who paints like Michaelangelo or Monet),

that makes me see the problem with what you said in your post.

It is the same flaw the entire psychological / psychiatrist majority has in its DSM-V proposal - and has existed in all past DSM versions that have messed up the diagnoses and count numbers numbers. Im not faulting psychs or you, only just out point in history.

It is thusly:

You can have all the fancy ways to measure verbal and language ability, and to debate all the nifty standard deviations, and such, you want, but ...

I can tell you from firsthand personal experience of living 53 years with non-verbal Autism and the characteristic brain function of a savant (Treffert & other medical research - PET scans), that your number crunching, and hence the DRAFT diagnostic criterion all are an EPIC FAIL for one single simple reason that needs to be fixed.

Language ability and your scores IN ACTUAL SCIENTIFIC FACT vastly differ depending on the format you use to allow the Autistic person to communicate when you test them. The DSM-V draft has not corrected this historic basic fundamental error created by the advent of the Printing Press before the Computer.

Doesn't anyone listen to Temple Grandin -- what does everyone thing "Thinking in Pictures" means, and "Animals in Translation." Not to diminish in any way Temple's AMAZING achievements, but she deals with cattle, I deal with language - so maybe I can explain it better.

"Thinking in Pictures" and "Animals in Translation" describes the inner experience of people who have the brain function type Treffert describes in those with left temporal area differences who operate on the same striatal circuits as animals (hence why we can "translate"). These differences uninhibit our Artistic - Pictures abilities, while severely impairing our language abilities on several fronts: ability to sequence, use limbic social-emotion roadways, follow speech sounds, and impacts phoneme chunking, syntax, symantics, pragmatics, word order within a sentence, and our ability to encode the same meaning to symbols as others; At the same time, enhancing our striatal tracks, so we become lightening fast at our savant abilities, which is most often Pictures-based and chunked in Pictures or musical sound units. I know, because I have battled the paradox every day of being a great artist but not able to write or speak anything anyone else -- other than another spectrumite -- can understand in a two way-shared fashion.

The result in the diagnostic testing is inescapably a HUGE DISTORTION if you use traditional industrial era paper / telephone style ways to test the language abilities of certain Autistics. Like me, and other savants and so-called "low functioning" people like Carly who are really articulate.

continued ...

Anonymous said...

If the DSM-V were improved to require Internet graphics-media style-hyperlink-database customizable formats, it is indisputable your number crunching result would change as compared to testing language abilities in print paper or via telephones. Don't forget there are many ways on the Internet to bridge foreign language translations and other communication gaps - it is, in essence, a "virtual PECs" system. One we can operate independently without some other "helper" censoring what we want to say (e.g., "facilitated communication" a/k/a The Ouija Board and other similar methods).

Another highly significant recommendation: As I have learned since I migrated to Twitter:
(1.) I can understand the conversation I receive from others if the sentence / thought structure is so simple it does not exceed 140 characters;
(2.) Other can understand me if I am forced to say my thoughts in only 140 character - very simple sentence structures.

THAT is how the tests need to be structure -- in Internet format.

I think I am highly Qualified to speak about all of this form EXPERIENCE since I can't understand anything if people are shoving paper print test instruments, intake forms, so-called "uninformed consent" paper print forms, etc in my face when I am a Thinking in Pictures synesthesete - I can't see the letters and I don't chunk information that way. Yet, I can write a White House level Supreme Court Cert Petition. In sum -- the Savant Paradox.

The DSM-V proposed draft leaves THAT huge flaw in the manner of testing language abilities that are going to be diagnostic, completely unaddressed. And at a time when you seem to have a young adult Aspie revolt going on in response to the Draft proposed DSM-V.

I think -- as Carly demonstrates, as I demonstrate, and a number of others I have encountered on the Internet demonstrate, you can get the Autism diagnoisis VERY WRONG if you test in conventional formats, instead of DRAFTING the DSM-V to INCLUDE IN THE DIAGNOISIS ITSELF that the language abilities may differ drastically (improve test scoring) if Internet computers with full 3-D Pictures and color capabilities are used to test some of us vs. the unreliable traditional prior-DSM formats.

I'm just saying.

I'm only trying to help out (and not be left out or living in fear someone will put a barrier to prevent my ability to effectively communicate because the DSM doesn't mention this diagnostic error flaw).

~EquiisSavant
non-verbal J.D./M.B.A.
An Artist who Speaks In Pictures and Dreams of Becoming a Lawyer

Anonymous said...

apologies for the typos, as I said, I chunk in Pictures, not letters / words. Sorry

corr: "count numbers numbers. Im not faulting psychs or you, only just out point in history." = count numbers. I'm not faulting psychs or you, only just our point in history.

"what does everyone thing 'Thinking in Pictures' means" = what does everyone think "Thinking in Pictures" means

Also, because I chunk in Pictures, not letters / words, I frequently leave off letters at the ends of words. I wont corr. those, because I think you can read what I tried to say.

I don't have the funds for a "proof reader" to fix my typos when I can't see letters / word forms, because adults with Autism are underfunded. Again, sorry.

Nevertheless, I thought someone had to say my response to your post.

David N. Andrews M. Ed., C. P. S. E. said...

"In areas of research I'm familiar with, T-scores, Z-scores, and 100-mean-15-SD, to give just three examples, can be referred to as standard scores, while the most frequent use is to refer to 100-mean-15-SD."

Strange. When I was studying psychometrics (as a postgraduate student in educational psychology), we learned the difference between standard scores (m=10, sd=3) and standard indices (m=100, sd=15) and other standardised scores (e. g., z-scores and T-scores and so on)... like it or not, Michelle, there is a difference. Deal with it.

Shitting Jesus, Michelle... anyone would think you have a hard time being told that you'd made a bloody mistake. You really do piss people off sometimes. I really wish you wouldn't.

Michelle Dawson said...

What I wrote can be verified by reading the referred-to literature.

Lili Marlene said...

Quote from blog:

"As wouldn't be predicted at all, the non-language-impaired autistics, who had advantages not only in language but on measures of intelligence, were the "severe" autistics, while the language-impaired children were the "mild to moderate" ones."

I'm guessing that this result could be due to kids having one main reason to be categorized as autistic - be it language impairment OR other autistic traits, suggesting that the diagnosis of autsim in language-impaired kids might be questionable, as the category of autism is too general to informatively describe their real difference from the norm. Does this make any sense?

Lili Marlene said...

And of course, the result could have been due the study having too few subjects and the effects of random variation.

Anonymous said...

Austim Liberation Front former member suggests that the DSM IV/V should recognize that a significant outcome of the diagnosis of autism provides entitlement to federal state and school district, medical, county, social, etc funding to support the education and development of the person with challenges within this spectrum of symptoms.

That said and put aside, the label itself, having been foisted upon the child, in and of itself becomes a major limiter of what that child will achieve in his/her life.

Having such a diagnosis provides funding for interventions (that, in schools, are often of questionable integrity/value and do not map to the childs specific symptoms to start with). Often a child is in an underfunded programs with under/ non-certified and under qualified providers and providers that lack understanding that these are differences in the way a person is being and learning in the world...not the labels given to provide for a free and appropriate education.

DSM V could eliminate the word autism and provide funding based on a wider range of symptoms for students..and not call it anything....besides what the symptoms require additional support for.
For example: symptom: difficulty following classroom procedures sequentially within 4 minutes of peers or requiring support to do so...this symptom requires specific supports...however, does not indicate the child is disabled. Example: delay or inability to have a fun break at recess. Intervention..small groups of children with mediated and explicitly instructed play=fun break for children with delays. Misinterpreting social queues = roll playing over and over again how to respond to bullies, recover when they have misinterpreted, how to use words rather than hands and feet to solve problems (including cool down first). etc.
Well..my point is...don't label...accommodate, modify and provide interventions for the challenges that are present.

Anonymous said...

Even autistics who are labeled "severely autistic" have hidden intelligence and demonstrate hidden talents that even the experts don't see.... For example, I know of a severely autistic person who has never spoken that has a photographic memory. She knows everywhere she's been no matter how many years later she's in that same place again. So never, ever assume people that people with severe autism are hopeless or are "lost causes." Autistic people think differently. They react to the world differently, but that doesn't mean they are stupid or are without hope. Many are "stuck" and require years and years of help and support to reach their full potential.