MONDAY, July 9, 2001 (HealthDayNews) -- When a fever triggers convulsions in a young child, the experience, while terrifying, usually has no long-term effects. Now, a new study surprisingly suggests that children with a history of fever-related seizures perform better on tests of working memory.
Febrile convulsions (FC) usually occur during the first day of a fever, when the child has a rectal temperature of more than 102°F. During the seizure, the child loses consciousness and shakes from several seconds to a few minutes, then falls asleep and later regains consciousness.
Doctors at the National Cheng Kung University College of Medicine in Tainan, Taiwan, studied 87 children, ages 7 and 8, who had experienced FC before age 3, comparing them with 87 children with no history of fever-related seizures. The study is described in the July 10 issue of Neurology.
Study co-author Dr. Chao-Ching Huang, professor of pediatrics and physiology, says several other studies linked a history of FC with normal or lower intelligence, but the research provided little information about the seizures' effects on other cognitive abilities, including memory.
Huang says he and his colleagues expected to find memory deficits in children with a history of FC. "To our surprise, our study result demonstrated instead that the children with a history of FC have better working memory than the controls," he says. The researchers used computerized neurological and cognitive tests to calculate the speed of mental processing,
But the findings don't mean that children with FC have an edge in the memory category. Instead, Huang says, "Our study suggests a more excitable brain makes the child more prone to FC and also superior in learning and memory." On the other hand, he says children with delayed development and a history of FC before age 1 had a higher risk for memory deficits.
A Huang says between 3 percent and 5 percent of children have at least one FC episode, and 30 percent of those children will experience another fever-related seizure before age 6. But only 2 to 5 percent go on to develop epilepsy, he says.
Huang says in general the convulsions do not appear harmful unless they last for more than 30 minutes, a condition known as febrile status epilepticus. "We are concerned [about] the consequence of prolonged FC since it suggests two possibilities. First, the prolonged FC can be caused by focal encephalitis, which has a different behavior and neurological outcome. Second, prolonged FC has the potential to damage the vulnerable brain areas such as [the] hippocampus, which in turn can cause subsequent intractable epilepsy and neurocognitive changes," he says.
Dr. Shlomo Shinnar, a pediatrician, neurologist and director of the Epilepsy Management Center at the Montefiore Medical Center in the Bronx, N.Y., says Huang's study shows it's now possible to test memory in very young children, and that could lead to other studies of children who experience prolonged FC. Huang's group is planning such a follow-up study.
Shinnar, who is a co-author an accompanying editorial, says, "Febrile seizures are the most common form of seizures in children
and, while generally benign, are very frightening."
"Febrile seizures need to be taken to the emergency room," says Shinnar, although the convulsions usually will be over by that time. "You need to get immediate medical attention the first time to make sure it is indeed a febrile seizure, rather than meningitis or some serious infection that's presenting with fever and a seizure."
Huang says, "FC is a very frightening experience to the parents," but the findings could help reduce some of the anxiety. He encourages parents to be optimistic, keep a close eye on their child's developmental performance and arrange a visit to the pediatrician if they have any concerns.
What To Do
For information about FC, check the National Institute of Neurological Disorders and Stroke and this reprint of an American Family Physician article at FindArticles.com.
This Web page from Monash University in Australia details how to respond when a child has FC.
