MONDAY, Dec. 3, 2007 (HealthDay News) -- Children with autism spectrum disorders (ASD) may show improvements in behavior when they have a fever, a small study suggests.
This is the first study to investigate a relationship between fever and behavior change in children with autism spectrum disorders (ASD), the researchers said.
"I think this study means there is hope, because it means that the basic networks in the brain in autism appear to be intact," said senior investigator Dr. Andrew Zimmerman, a pediatric neurologist at the Kennedy Krieger Institute in Baltimore.
According to the authors, ASD includes autism, autistic disorder, pervasive developmental disorder not otherwise specified (PDD-NOS) and Asperger's syndrome.
The new study adds to a growing body of research that suggests that the problems children with ASD have with behavior, language skills and social skills result from poor connections between synapses in the brain. The question, Zimmerman said, is which synapses are involved and how to stimulate them to function.
Zimmerman said the heat of a fever might stimulate changes at the cellular level. Fever's impact on the hormonal and immune systems might also be responsible for the perceived changes in the children. The changes observed in the study were not permanent, however, and disappeared within a week of the fever's end, the researchers noted.
Zimmerman also noted that the effect seems limited to viral fevers, such as flu-related fever, rather than other illnesses.
"This is a very interesting study," said Dr. Annette Estes, associate director of the University of Washington Autism Center, who interpreted the study's results in the context of a new line of research that is linking autism to immune system response and inflammation.
"This is a novel use of a child who is ill with fever," she said. "I'd like to see someone replicate this observation and make sure that this study with a small number of children holds up."
"This is the first step in a really long series of studies that needs to be done," Estes added.
In their work, Zimmerman's team compared data from 30 children with ASD who had a feverish episode, with 30 similar children with ASD who did not have a fever. Once a child had a fever, the parents were asked to observe their child for 24 hours and then complete a questionnaire about behavior and language ability. They completed a second questionnaire 48 hours after the fever and a third questionnaire after seven days without fever. Parents of the non-feverish children filled out the same questionnaire at the same times about their own child's behavior and language ability.
The study results, published in the December issue of Pediatrics, showed fewer autistic-like behaviors for children with fever, compared to the children without fever, with more than 80 percent of the fever participants showing some behavioral improvement.
Estes, who uses the same behavior checklist in her research that the researchers used in the study, cautioned that the checklist is not specific to children with ASD, nor is it used to diagnose ASD. It is used to assess behavior in children with a variety of developmental disorders, including mental retardation, genetic diseases and Down syndrome, she said.
"The checklist is used to understand other behaviors that children with autism have troubles with," Estes explained. Irritability and lethargy are among those problem areas, she said.
The fatigue associated with illness may seem a natural explanation for the changes in behavior, but the study authors found lethargy was not a factor.
"We stratified subjects based on their level of lethargy and we did not find a difference. Children in both groups, whether their lethargy was high or low, had benefits," said study lead author Laura Curran, research assistant at the institute.
The study may provide hope for future avenues of ASD research. But it also provides an important piece of information for professionals who must evaluate children with the disorder, the researchers said.
"This research adds to the literature of understanding the underlying neurological and behavioral aspects of ASD in that it assists with setting a context for evaluation and treatment. It will be important for diagnosticians to query parents and guardians as to how recently the child had a fever because it may diminish behaviors that need to be assessed," said Michael Morrier, assistant director for research and program evaluation at the Emory Autism Center in Atlanta.
Morrier said he would like to see more in-depth study of the effect.
Autism may strike one in every 150 American children, according to statistics released earlier this year by the U.S. Centers for Disease Control and Prevention. Males are four times more likely than females to be diagnosed with the disorder.
More information
To learn more about autism, visit the U.S. National Institute of Mental Health.
