Esthart has copied and pasted the DSM-IV "autism" diagnosis here. The American Pediatrics Association indicates:
"Autistic disorder is the term used when a child meets all the necesary criteria listed in the DSM-IV. Children with autistic disorder have problems with language skills that are absent, delayed or abnormal; problems relating to others socially; and unusual or repetitive behaviors. While social symptoms are usually present in the first year of life, language problems show up in the second year and stereotypic behaviors show up later." [Emphasis added.]
Source: Understanding Autism Spectrum Disorders (ASDs)
The "autistic spectrum", which is almost universally adopted, is comprised by autism (as defined above), aspergers and "PDD-NOS". AAP describes PDD-NOS as follows:
Children with PDD-NOS or atypical autism show some signs of autism or other PDD, but don't meet the criteria to be diagnosed with one specific disorder.
Source: Understanding Autism Spectrum Disorders (ASDs)
I use the term "mild autism" to refer to PDD-NOS, and the term "classic autism" to refer to autism as defined above. I argue that the distinction between the two is one of degree or quantity, and not of quality. This is far from commonly accepted. Many object to the term "mild autism" because the connotation may be a lesser need for services, and many parents with children on the mild end of the spectrum embrace these services. However, I don't believe in diagnosing for services or adopting nomenclature to justify services. Rather, I believe in intellectually honesty above all.
I don't use the label "HFA" or high functioning autistic. While I endorse the notion that autism exists in gradations or degrees, I don't believe that we have to measure degree by reference to function. My son is generally pre-verbal and is still in diapers. He certainly doesn't qualify as "high functioning." Yet, he is distinguishable from other autistics in terms of degree. Hence, my preferred terms "a little bit autistic" and "mild autism." "High functioning autism" is an analytical void, from my son's perspective.
What then do I mean when I write, for example, "my son is autistic"? I don't mean that he has classic autism. Instead, I mean he's on the autistic spectrum.
Now, lets loop back to the central assertion that is causing the members of the late talker group so much consternation. Namely, that late talkers are per se mildly autistic. Again, I'm not
suggesting that any of the late talkers have classic autism.
As summarized above, children with PDD-NOS or mild autism present with symptoms from three general categories: language, social and behaviors. Late talkers, by definition, have a significant language delay. Socially, by definition, most late talkers present as aloof or, as Sowell euphemestically puts it "strong willed." Sowell further concedes that these children often have difficulty sustaining eye contact and responding to their name. These "traits", in the aggregate, are generally enough to implicate social impairment for PDD-NOS diagnostic purposes.
The remaining category, behaviors, is nebulous when it comes to late talkers and mild autism, especially in the preschool years. Toddlers - neurotypical and autistic alike - tend to cling to nonfunctional routines, and engage in repetitive behaviors such as lining up blocks. Dr. Greenspan describes this category as secondary, and includes within its scope the tendancy to: "persevate (for example, lining up objects repetitively), flap hands, or self stimulate (for example, staring at a fan, rubbing a particular spot on the floor, and so forth)." (Source: Engaging Autism. ) Hence, this category is related to sensory dysfunction. With respect to mild autism, if the sensory dysfunction is mild, then so too will the resulting symptoms, if any.
In sum, my sweeping generalization - that late talkers by definition are mildly autistic - isn't a leap in logic at all. And that is why Sowell argues that the spectrum itself doesn't exist, rather than arguing that late talkers don't meet the diagnostic criteria.
Now lets explore differential diagnosis. SarahGepp invited me to weigh in on this issue (here):
"[W]hat is the true difference between HFA and a speech delay that includes other subtle developmental issues such as sensory disorders?"
If it's just speech delay and mild sensory issues, I wouldn't say it's mild autism unless there were also a social impairment. She describes her son as follows:
My three year old is very friendly, intelligent, and engaged but there are some things he does that have me wondering. He scripts more frequently than most kids his age, for instance. He also loves fans and turning on and off light switches which I think goes beyond just a normal curiosity with cause and effect. He also has some sensory issues (both sensory seeking and sensory avoiding). Also, since the minute he could get around he has tried to escape. (In the autistic community this is referred to as elopement and often is tied into sensory issues.) He does not have some of what people might consider the more "common" behaviors you see with kids with ASDs. He does not flap or spin or line things up, for instance. He has good eye contact, seeks social contact (although he get overwhelmed in groups) and he does not have
atypical meltdowns. He is also is in a Montessori school with NT children and does well. That does not, however, clear him from being a child who would benefit from some of the therapies geared towards autistic children. Much of what I observe about him is just a "feeling" that something is not right. He has an incredible memory and
with probably turn out to be an early reader, but I think that these traits go beyond just being exceptionally intelligent. When I interact with him it is just obvious to me that he is not your NT kid." [Emphasis added.]
It's not my place to ascribe a diagnosis to any particular child. I would follow my instinct, if I were you. Just don't be afraid of doctors. That's my message. The issue of eye contact is interest to me. Brad makes good eye contact too. When he was evaluated, however, they said he didn't use it to regularly "check in", the way a neurotypical child does. It's subtle, but detectable. In terms of the sensory issues, I recommend that you read the book, The Out of Sync Child.