Fever eases behavioral problems in some Autistic children

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About 17 percent of children with autism are calmer and more communicative than usual when they have a fever, according to a new analysis1. Children with severe autism features are most likely to show these gains.

Lord and her colleagues studied 2,152 children with autism in the Simons Simplex Collection (SSC). The SSC is a database of information from families that have one child with autism and unaffected parents and siblings. (The SSC is funded by the Simons Foundation, Spectrum’s parent organization.)

As part of their participation in the SSC, parents described their children’s medical history via questionnaires and interviews. One question asks parents whether their child’s behavior seems to improve during a bout of fever. Parents of 362 of the 2,152 children answered ‘yes.’

Specifically, parents reported that fever improves their children’s ability to learn, communicate and interact with others. It also lessens the children’s repetitive behaviors and tantrums.

Lord and her team used data from the SSC to look more closely at these children’s genes and behavior.

They found that having a genetic variant associated with autism does not influence the chances that a child will improve with fever. The children who do improve have significantly lower nonverbal cognitive skills and language abilities, and more repetitive behaviors, than do those who don’t change with fever.

The study’s 17 percent estimate falls short of Zimmerman’s finding of 83 percent.

In that study, Zimmerman’s team asked parents of 30 children with autism to complete a standard behavior checklist at the onset of one bout of fever in their child. The parents completed the same checklist when the fever abated, and again one week later.

Because these parents knew what the researchers were looking for, some of them may have reported an improvement that wasn’t there, Zimmerman says. On the other hand, parents may only notice the improvement if they’re looking for it, he says. “That’s why I think the 17 percent is probably a baseline.”

Lord agrees that the 2007 estimate may be inflated. She notes that her team’s approach — asking parents to recall their child’s behavior during fever — may have yielded an underestimate. “We could have bias in the other direction,” she says.

Why fever alters behavior in some children with autism is unclear. Lord and Zimmerman say there is anecdotal evidence that people with other neurological conditions, such as attention deficit hyperactivity disorder or Alzheimer’s disease, may also show behavioral improvements during fever.

Some of the behavioral changes during a fever could stem from lethargy — the calm demeanor induced by illness might result in fewer outbursts, for example. More research is needed to rule out that idea, researchers say.

It is also unclear whether the children who improve during fever are more impaired than those who don’t seem to change, says Audrey Thurm, a clinical psychologist at the National Institute of Mental Health in Bethesda, Maryland, who was not involved in the work. It could be that parents of children with severe autism features are more likely to notice behavioral changes than are those of children with milder features, she says.