SAN FRANCISCO, Oct. 11 (UPI) -- At its most basic level, part of the debate over the cause and consequence of the climbing numbers of autism diagnoses among America's young centers on bookkeeping.
Defining, documenting and recording cases in systematic and consistent fashion over the years, and decades, is a key step for properly accounting for current trends -- and even more importantly for correctly calculating the deposits to be made, in research, education, services and funding, to cover the growing costs of these youngsters' special needs.
One of the most glaring items left blank in the ledger comes under the heading of prevalence.
While the accuracy of statistics of affected children is steadily improving, the figures are missing a historical context.
As one challenge, it was not until 1980 that the official criteria for identifying autism made it into the official handbook of mental disorders used to make a diagnosis.
Before that year, scientists say, estimates of autism prevalence were based on little more than the conceptions of individual clinicians or researchers, which fluctuated with the size of the population sampled and manner of identification used.
More recent years also have seen little stability in the diagnostic criteria, which -- just as in the case of attention-deficit/hyperactivity disorder, depression and other mental illnesses -- have loosened up over time.
Thus, the 1980 requirement of "a pervasive lack of responsiveness to other people" has been relaxed to a requisite for only "a lack of spontaneous seeking to share enjoyment, interests, or achievements with other people."
Likewise, the criterion of "gross deficits in language development" 14 years later became the more inclusive difficulty to "sustain a conversation with others."
Whereas the 1980 autism definition comprised only two diagnostic categories -- "infantile autism" and "childhood onset pervasive developmental disorder" -- the 1994 version swelled to five "pervasive developmental disorders," the scientific jargon for autism spectrum disorders, that range in severity from having little speech and few daily-living skills to functioning well in most settings.
Three of these connote what is commonly called autism: the severe autistic disorder, the much milder Asperger's syndrome, and the tongue-tripping "pervasive developmental disorder not otherwise specified," PDDNOS in doctors' shorthand, which lumps together children who show symptoms but do not meet the criteria of either of the other two conditions.
The two remaining members of the group -- both rare but severe -- push the reverse button on development.
Unlike the other four syndromes that affect some four times as many boys as girls, the hereditary Rett's disorder -- named after Australian doctor Andreas Rett who identified it in 1965 -- is almost entirely restricted to females.
Most boys with Rett's die before birth.
The syndrome, caused by a defective gene on the X chromosome, emerges sometime between six months and 18 months in an estimated one in 10,000 to 15,000 girls, eating away at muscle tone and wreaking neurological havoc.
What up until then appears to be normal development halts and retreats. The toddler begins rejecting parents and peers, ceasing to speak if she was already talking, losing control of her feet, wringing and waving her hands, suffering seizures and developing an awkward gait, according to the diagnostic manual.
In similar fashion, "childhood disintegrative disorder," which makes its appearance as early as age 2 or as late as age 10, erases many of the social, language and cognitive skills the child has acquired. These may include speaking, relating to others, engaging in make-believe play, and controlling the bowel and bladder.
Unlike ADHD, which is most likely to be first noted by teachers, initial autism detection usually falls to parents.
Fresh from the hospital, they may immediately remark that the newborn seems "different," unresponsive to people or focusing intently and enduringly on a single object. At other times, symptoms may cut short what had appeared to be perfectly healthy development.
Although refined since psychiatrist Leo Kanner reported the first documented cases of the disorder, the fundamental symptoms he described have been largely retained in the diagnostic criteria for classic autism.
Social interactions are severely limited. So much so, the typical rules of engagement -- detailed in every new parent guidebook -- do not apply.
Small chance of playing peek-a-boo or hide-and-seek with a baby who avoids eye contact or stays secured in his isolated world. Slim odds of eliciting a smile, laugh or cuddle from a child who seems to prefer the crib to his parents' arms.
Many autistic individuals, including adults, cannot read facial expressions, body postures or gestures, ordinarily a natural-born skill perfected early in life, doctors say.
This "illiteracy," they note, can make the most common social situations bewildering for someone who derives similarly puzzling meaning from a smile as a sneer, from an open hand as a clenched fist.
Speech is impaired. Some children never utter a word. Some make idiosyncratic use of language or only eerily echo what they hear.
Repetitive behaviors are typical. Little ones rock, spin, flap hands, twist bodies in an endless encore.
Although Kanner was convinced all autistic children are born with the condition, subsequent studies suggest up to a third may regress to it.
More common, less severe, Asperger's syndrome affects some 35 of every 10,000 children.
Although no social butterflies and prone to unusual, repetitive mannerisms and in some cases learning challenges, these youngsters are less apt to face delays in the development of language, cognitive or daily living skills.
In some instances, they may have the IQ of a prodigy, though it is likely coupled with the sociability of a hermit, according to the psychiatric diagnostic manual.
A small number can blend into the mainstream.
Many take issue with being singled out as "abnormal" or stigmatized as "deficient," asserting they stand out no more than other idiosyncratic individuals and urging greater acceptance of their differences, which may not be as sizeable as commonly perceived.
Indeed, some researchers are beginning to question the widely held assumption that autism steals away the so-called "theory of mind," the ability to comprehend divergent points of view.
Other physicians, however, caution against becoming overly blasé about the special needs of a youngster with even minimal symptoms.
"The sort of stereotype of the Asperger's child is that they're all going to go to MIT and be Bill Gates and start Microsoft and be millionaires, and who cares how weird they are," said Dr. Eileen Costello, a pediatrician at the Boston University School of Medicine, co-author of "Quirky Kids"(Random House, 2003), and mother of a 14-year-old son with mild Asperger's.
"And, you know, that's true for a small segment of this population, but it's just too appealing to think that that's where they're all going, because it just isn't true."
These less severe forms of autism, which weren't listed in the diagnostic manual until 1994 and thus would be on a steep rise since then, account for nearly three-fourths of the current diagnoses, guesstimate researchers who argue against an autism epidemic.
"My personal impression is yes, there's an increase in this population, but it's a very complicated question," Costello said.
Next: Changing face of autism
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