Speech impairment and autism, inseparable?

11 Jun

In a recent paper purporting to link autism and vaccines, the author, Gayle DeLong, chose to lump autism and speech or language impairments together to create an autism “prevalence” from special education data:

To determine autism prevalence by U.S. state, the number of 8-year old students classified with either (1) autism or (2) speech or language impairments (speech disorders) was divided by the total number of 8-year-olds in the state.

The author has defended the choice over at the Respectful Insolence blog:

Orac,
I won’t respond to the personal attacks, but I will correct one error. The Herbert reference in the paper is incorrect. The correct citation is: Herbert and Kenet (2007) Brain abnormalities in language disorders and in autism. Pediatr. Clin. North Am. 54:563-583 (abstract: http://www.ncbi.nlm.nih.gov/pubmed/17543910). The paper shows that brain injury of people with autism is similar to brain injury of people with speech and language disorders. Another paper that makes much the same point is Herbert et al. (2002) Abnormal asymmetry in language association cortex in autism. Ann. Neurol. 52:588-596 (abstract: http://www.ncbi.nlm.nih.gov/pubmed/12402256).

Speech impairment is such a fundamental symptom of autism that the two conditions cannot be separated, especially when the child has a speech/language impairment that is strong enough to be classified as a learning disability.

First, kudos to Ms. DeLong for taking her statement to Orac’s blog. The participants are clearly not supportive of her statements–such as:

“Speech impairment is such a fundamental symptom of autism that the two conditions cannot be separated, especially when the child has a speech/language impairment that is strong enough to be classified as a learning disability.”

All I can say is that I disagree. Strongly.

Here is the definition that California uses for Autism as a special education category:

56846.2. (a) For purposes of this chapter, a “pupil with autism” is a pupil who exhibits autistic-like behaviors, including, but not
limited to, any of the following behaviors, or any combination thereof:
(1) An inability to use oral language for appropriate communication.
(2) A history of extreme withdrawal or of relating to people inappropriately, and continued impairment in social interaction from
infancy through early childhood.
(3) An obsession to maintain sameness.
(4) Extreme preoccupation with objects, inappropriate use of objects, or both.
(5) Extreme resistance to controls.
(6) A display of peculiar motoric mannerisms and motility patterns.
(7) Self-stimulating, ritualistic behavior.
(b) The definition of “pupil with autism” in subdivision (a) shall not apply for purposes of the determination of eligibility for
services pursuant to the Lanterman Developmental Disabilities Services Act (Division 4.5 (commencing with Section 4500) of the
Welfare and Institutions Code).

One can not say that SLI and autism are directly linked.

The data don’t support it either. Her own paper gives administrative prevalence numbers for autism+SLI which are as high as 10%, about a factor of 4-10 than reported for autism.

Also, consider this: if you look at the administrative prevalence of SLI with age in a given year, it is sharply peaked at around age 6 or seven. Here are the data for SLI and autism from the most recent year data are available in California. (click to enlarge)

(note–when this was first published, the graph was not in color).

No, that isn’t a “tidal wave” of SLI. This is what SLI looks like every year. It is a category mostly for younger children. I’ve often wondered if many of these children end up in the specific learning disability category in later years as this category is largely made up of older kids. Either way, it is clear that children tend to leave the SLI category, and they certainly aren’t being reclassified as autistic. Clearly, SLI is not something which can not be separated from autism.

I don’t know why Ms. DeLong chose to lump autism and SLI together for her study. I do feel quite strongly that the idea that they are basically the same is incorrect.

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13 Responses to “Speech impairment and autism, inseparable?”

  1. Jon Brock June 11, 2011 at 01:20 #

    Herbert and colleagues reported that there was some similarity in the structural abnormalities of one cortical region (Broca’s area) in kids with SLI and kids with autism who have language difficulties (but not in autistic kids with age-appropriate language). It’s an interesting result, because the region in question is known to be very important for language. it’s feasible that abnormalities of Broca’s area cause language impairment in both groups (although it seems just as likely that the reverse is true). But it’s one small region of the brain. To say that the nature of “brain damage” is similar in autism and SLI is to ignore the whole of the rest of the brain!

    PS. I think the reference she was looking for was De Fosse et al 2004 (also in Annals of Neurology) – the Herbert et al 2002 study doesn’t have any kids with SLI in it!

  2. Dorothy Bishop June 11, 2011 at 06:08 #

    I’m a Professor at Oxford University who has spent my entire career researching specific language impairment. While there has been some debate about boundaries between SLI and autism (see publications list on my website: http://psyweb.psy.ox.ac.uk/oscci/Publications%20Dorothy%20Bishop.htm), nobody would ever dream of treating them as interchangeable. It has never been suggested that SLI is caused by vaccination; it is highly heritable and typically involves very slow onset of language from the earliest stages. It is also considerably more common than autism.

  3. Nicola Botting June 11, 2011 at 08:55 #

    As another researcher in this field I strongly echo the views of my colleagues above, the evidence for SLI and Autism overlap is complex (see Williams, Botting & Boucher 2008) and to suggest they are the same disorder does nothing to further theory or support for families. With measles on the increase again the suggestion of a link between SLI and vaccination is a dangerous one. I was interested in the prevalence graph – from our own data one possibility is that older kids with SLI or primary language difficulty present with a much more generalised picture of difficulty, so may be classed as generally learning disabled (Botting,2005). However since services for adolescents are much less geared up for recognising spoken language difficulties, these children may also be picked up via literacy assessments and be described as having specific reading difficulties. Our longitudinal data confirms your point that these children are not generally redefinable as autistic as they get older (Conti-Ramsden, Simkin & Botting, 2006).

  4. usethebrainsgodgiveyou June 11, 2011 at 11:59 #

    Village idiot here…(self-defense mechanism?)

    For all intents and purposes, SLI will be intertwined with Autism. Labeling goes on at a grassroots level, not in the ivory towers. My son was semantic-pragmatic to a neurologist, but treated as “educationally Autistic” (a name specific to that school district) in his education program. In this age, realistically, everything that is language oriented looks like autism. Ask the Koreans. Quack…

    For all intents and puposes at the grassroots level of education, where most children are treated, there is tremendous confusion regarding all LD’s, and many previously diagnosed as children who were once considered Dylexic, now have a diagnosis of Autism, or vise-versa in my son’s case. I diagnosed him. Dyslexics have better P.R. people.

    @Dr. Bishop, I recalled your name recently, and a year ago had posted about you. Look at the comments, which give kudo’s, but reiterate my point.http://hardwonwisdom.blogspot.com/2010/02/is-spld-autism-or-not.html

    I have nothing of substance to say regarding DeLong’s paper, except that she has inadvertantly brought up a pecadillo of professional labelers of our children. They seldom agree.

  5. Stuart Duncan June 11, 2011 at 12:22 #

    I often lump things together when it suits me too. Bacon and eggs are virtually the same thing because you can’t have one without the other.

  6. BTDT June 11, 2011 at 14:56 #

    I just want to remind everyone that the DeLong paper uses data for the rates of children who are placed in the Speech and Language Impairment category in order to receive special education services. To be able to receive special education services in the U.S., a child is assigned to one of the categories specified in the Individuals with Disabilities Education Act (IDEA). The Speech and Language Impairment (SLI) category, is not interchangeable with Specific Language Impairment (also abbreviated SLI).

    States all of have their own definitions of the IDEA categories, this is California’s definition of Speech and Language Impairment:

    “A student with a Speech Language Impairment is defined as a pupil who has been “assessed as having a language or speech disorder which makes him or her eligible for special education and related services when he or she demonstrates difficulty understanding or using spoken language to such an extent that it adversely affects his or her educational performance and cannot be corrected without special education and related services” (CEC, Section 56333).”

    This category would include children who have speech difficulties, such as fluency, articulation, and voice issues, as well as those who have true language impairments.

  7. BTDT June 11, 2011 at 15:11 #

    I should also add that all of the references cited in the DeLong paper to justify the inclusion of Speech Language Impairment, actually refer to Specific Language Impairment.

  8. Jon Brock June 11, 2011 at 23:32 #

    BTDT: I only realised as much after I’d commented and read the full Orac post and comments. It makes no sense to lump together autism and specific language impairment and even less sense to lump together autism and speech language impairment.

    The other non-obvious thing I realised from your post is that different states have different criteria for speech language impairment. So to compare prevalence data at the state level is utterly meaningless (notwithstanding all the other serious problems with the study).

  9. David N. Andrews M. Ed., C. P. S. E. June 12, 2011 at 09:39 #

    “For all intents and purposes, SLI will be intertwined with Autism. Labeling goes on at a grassroots level, not in the ivory towers. My son was semantic-pragmatic to a neurologist, but treated as ‘educationally Autistic’ (a name specific to that school district) in his education program. In this age, realistically, everything that is language oriented looks like autism. Ask the Koreans. Quack…”

    What in the name of fuck is ‘educationally autistic’?

    “For all intents and puposes at the grassroots level of education, where most children are treated, there is tremendous confusion regarding all LD’s, and many previously diagnosed as children who were once considered Dylexic, now have a diagnosis of Autism, or vise-versa in my son’s case. I diagnosed him. Dyslexics have better P.R. people.”

    True, the dyslexic me has better PR folks (Tim Miles, Susan Hampshire, and the like) than the autistic me has. Not that it makes that much difference: the autistic David and the dyslexic on live in the same body and are (states obvious) the same person.

    In most cases, I’d say that you identified your son’s autism but – well, I know you have a qualification in the are of special educational needs and that you’ve done your homework and that – if called upon, you could essay the dx quite well…well done on doing so. Did you get any flak from the school district for having done so? My daughter has three separate professionals’ diagnoses: one from the ARC at the University of Cambridge, one from the local hospital, and one that I did as part of my practical studies in assessment and diagnosis. The local education mob here are still arsey about it, but they know that her mum and I are not to be messed about.

  10. David N. Andrews M. Ed., C. P. S. E. June 12, 2011 at 09:40 #

    comment in moderation.

    typo correction: are -> area

    laptop keyboards are annoying!

Trackbacks/Pingbacks

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    [...] Originally posted here: Autism Blog – Speech impairment and autism, inseparable? « Left … [...]

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    [...] and Childhood Vaccination uptake across the U.S. Population. Prometheus and Sullivan have already had a go at this wretched bit of autism “science,” but I’ll briefly comment as [...]

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