Fevers could actually improve autistic behavior in children, new research suggests, hinting at the possibility of a biological cause behind the disorder that has proved so difficult for experts to understand.
Researchers from the Kennedy Krieger Institute in Baltimore report that autistic children who are sick are less likely to make repetitive movements, use less inappropriate speech and are not as hyperactive as they normally behave.
"As a parent of a child with autism, I don't know why it happens, but I do witness how calm my son is when he is sick," said Marguerite Colston, parent and director of communications at the American Society of Autism (ASA).
"He can cuddle and is very calm, even looks me in the eye occasionally. His behavior is markedly different. I would love to hear more about why he reacts the way he does."
The behavior Colston describes has been observed by parents for years, but this is the first scientific study to investigate the issue. Researchers asked parents of 30 autistic children to evaluate their behavior during and after an illness.
They found that a fever of at least 100.4 degrees Fahrenheit improved symptoms such as arm flapping and body rocking, as well as irritability and hyperactivity.
Is Lethargy From Fever to Blame?
Of course, some experts are skeptical that sluggishness associated with the fever causes children to be less energetic. Deborah Fein, professor of psychology at the University of Connecticut, says that because of the design of the study, this possibility cannot be ruled out.
"I do not think that the methods used are sufficient to rule out lethargy as a contributing factor, and the improvements she reported are all reductions in negative behaviors that could reasonably be related to slowing of activity levels," Fein said.
However, she adds that in some cases parents observe certain qualities that suggest fever may actually improve symptoms.
"One thing that parents have sometimes reported to me is actual improvements in eye contact, emotional relatedness and functional use of speech," she said.
"If these were shown to improve in a similarly controlled study, this would really argue against lethargy as an explanation, since it would be hard to imagine how lethargy could improve social relatedness."
Martha Herbert, an assistant professor in neurology at the Harvard Medical School and research adviser for the ASA, agrees.
"If the only change were a reduction in hyperactivity, you might attribute this change to lethargy," she said. "But … because many parents report that their children make more eye contact and are more socially related with fever, further study is needed using measures that are more sensitive to these levels of functioning."
The study, however, is still a preliminary one and some urge caution in interpreting the results.
"This is a very preliminary study whose main purpose is to set the stage for a bigger, better one … that is not just based on parental report and that has better controls," said Steven Goodman, an associate professor of pediatrics at the Johns Hopkins Schools of Medicine and Public Health in Baltimore.
"It is very unclear what a parent of an autistic child, or even researchers, would do with this information at this time. This will merely set up a number of questions to be explored in future studies."
But some believe that it brings scientists one step closer to discovering whether or not faulty nerve connections in the brain or imbalances in chemicals are at the root of the disease.
The ASA for example, says the study is a "very significant contribution to research" because it looked at the biological, and not merely genetic, causes of autism.
"This is a very important study for its small size, because it shows that severity of some things can change," said Herbert. "And it means that something biological that comes with fever is related to this change. This study has produced some very valuable clues to the autism puzzle."
Mechanism Remains a Mystery
Although fever appears to have the ability to change behavior, experts still can't explain exactly why this is the case.
The authors suspect that fever causes changes in the brain, influencing the connection between nerves or perhaps the levels of neurotransmitters in the brain, but they cannot say for sure.
Nonetheless, Herbert agrees with the authors that fevers may alter the brain at the cellular level.
"The first thing we would suspect would be substances that circulate in the blood when we have a fever, called cytokines," she said. "It's also possible that cell membranes or cell receptors function differently when they are hotter. Networks in the brain may function differently, or the energy metabolism in cells in the brain may change in autism."
If researchers can discover how fever improves conditions, they may be able to develop drugs that could act in the same way. Unfortunately, though, that prospect remains a long way off.
"This is a very interesting finding worthy of future investigation to see if it begins to reveal a clearer understanding of the mechanisms involved in the cognitive impairments in autism, which could ultimately yield a therapeutic intervention," said David Beversdorf, assistant professor of neurology at the Ohio State University Medical Center in Columbus.
In the meantime, however, experts warn that parents should not induce fever in their children or withhold medical treatment to replicate the reported improvements in behavior.
"This [study] doesn't mean that children should have more fevers," said Herbert. "But it does mean that something about fevers relates to something that influences the autism, and this is a significant clue about how autism may work."