The study compared 30 children on the autism spectrum (12 with autism, 11 with PDD-NOS, two with Asperger syndromeand five with some other ASD) with 30 other autistic children who matched them in age, gender, and language skills. When one member of the pair got sick (with any illness that caused a fever of at least 100.4 degrees), the parents of both children would answer the questions on the Aberrant Behavior Checklist, which asks about five categories of odd behavior: irritability, lethargy, hyperactivity, stereotypy (repetitive movements, rituals ... common autistic ones are hand-flapping or rocking; a common neurotypical one is pacing the floor), and inappropriate speech. There were three points in time when these data were collected: during the fever, while the fever was going down, and when the child had gotten well again.
The study found that on four of the five subscales (irritability, hyperactivity, stereotypy, and inappropriate language), the feverish children scored significantly lower (i.e., more normal) than the nonfeverish ones. They scored higher on the lethargy subscale (which, along with the lower levels of hyperactivity, should surprise no one; they're sick!). The researchers did some fairly exhaustive statistical analysis to determine the extent to which the lessening of "aberrant" behaviors could be ascribed to the children's lower overall level of activity due to the sickness, and finding that lower scores on the four subscales were unrelated to either the severity of the fever or higher scores on the lethargy subscale. So, while general tiredness and malaise probably accounts for some of the change, it can't be the only factor at work, or else the kids with the highest fevers, or highest lethargy scores, would consistently be the ones to show the most improvement, which they're not.
There are a lot of limitations on this study, though: for one, the study population is really small (only 30 kids, plus the 30 controls) and represents a mind-boggling variety of ages, abilities, medications and other confoundings factors; second, the kids did not all have the same sickness. The only criterion for inclusion in the experimental group was that they have a fever. That could be any number of different infectious agents.
The researchers themselves have a list of methodological weaknesses, too:
Although subgroup comparisons suggest some specificity of the fever effect, the study did not include a comparison group of children with nonfebrile illnesses. Our measures of behavior were based solely on parent reports; these data are subject to information biases. Because symptom data were collected prospectively, however, recall bias, a major source of information bias, was likely limited. Future studies may benefit from including independent raters (eg, teachers) or using videos to limit subjective misclassification of changes in behavior. Selection bias is also possible because a small fraction of eligible families from recruitment sources participated. Just more than half of families in the final analysis sample reported a priori that they thought that fever affected their children's behaviors, and this proportion may be higher than that of the general population of parents of children with ASDs...
So, in the final reckoning, what we have here is a slightly more systematic recording of what had previously existed only as anecdote. The sample size is too small and the number of confounding variables is too large to say they've definitively isolated a trend. If anything, the study points as much to our ignorance of fever, and what happens to the body during a fever, as it does to our ignorance of autism. Both topics certainly merit further study.
It wasn't really my intention to be so long about the technical aspects of this article; I'll try to be brief and just mention in passing its metaphorical subtext. The old wives' tale the researchers were investigating has it that during a fever, autistic symptoms will diminish, sometimes dramatically. It's as if a veil has been lifted, goes the metaphor, and parents can see their *real* child before he slips behind the haze of autism once more.
This kind of revelatory moment exists also in the changeling myth, which I attempted in the last post to argue is the lens through which most people still see autism. If you have a changeling, legends say (as per Wikipedia) that you can cause it to reveal its true nature, usually by doing something odd like brewing beer in an acorn shell. The changeling will then say something highly ritualized that no human child would say, like "I've seen (a lot of things, indicative of the fairy child's great age), but I've never seen beer brewed in an acorn shell," and then either disappear, leaving the human child, or stay there, revealed, and the parent would have to think of a way to drive it away and regain his or her actual offspring. I think the belief that autism will abate during a fever calls back to this scenario: a specific set of circumstances reveals the enigmatic, frustrating child as he really is, and gives the parent hope that he or she won't always be stuck with a cipher. It externalizes the child's autism, makes it something that has happened to the child rather than part of who the child happens to be. And it might well give the parents hope to think of their child this way, but I think it's a false hope, or at least a severely conditional one. It predicates happiness on the child's finding its way to socially acceptable normalcy, whereas when one accepts autism as not being inherently bad, just different, one is able to love and take joy in the child regardless of outcome.