Working memory of school-aged children with a history of febrile convulsions: A population study

Objective: A prospective, population-based, case-control study was performed to ascertain whether febrile convulsion (FC) in early childhood is associated with specific working memory characteristics in school age. Methods: From a population survey of 4,340 live-birth newborns in Tainan City, Taiwan, 103 children with confirmed FC by age 3 years were followed-up until they were at least 6 years old. Three analogous searching tasks dissociating the mnemonic and executive aspects of performances were administered to 87 of these school-aged children and to 87 randomly selected age-matched control subjects to assess the learning, spatial, and sequential working memory. Results: The FC group performed significantly and consistently better than control subjects on all but one working memory measure, jumping errors. Multivariate analysis using linear regression revealed that the onset of FC before age 1 year was the only significant risk factor for deficits in mnemonic function. Prior neurodevelopmental delay was the only significant risk factor for deficits in executive function. Factors such as socioeconomic status, family predisposition for seizures, complex FC, recurrent FC, and subsequent unprovoked seizures were not risk factors for working memory deficits. Conclusions: The authors found that school-aged children with a history of FC demonstrated significantly better mnemonic capacity, more flexible mental processing, and higher impulsivity than their age-matched control subjects. The underlying mechanism for the facilitated working memory function in children with a history of FC needs further delineation.