Intraindividual variability in attentional vigilance in children with epilepsy.

Attentional vigilance, the ability to maintain focus over time, is frequently impaired in childhood epilepsy. Typically, indices of Omissions (failure to detect a target) and Commissions (responding to a nontarget) are considered primary indices of attentional vigilance. Recently, the concept of intraindividual variability (IIV) has been identified as an important measure of attentional vigilance in several pediatric and adult clinical populations, but has not yet been systematically examined in childhood epilepsy. Here, we examined IIV on the Connors Continuous Performance Task-II (CCPT-II) for 144 newly diagnosed children with epilepsy (age 8-18years) and a matched age group of healthy children (n=82). Intraindividual variability showed a large effect size difference (d=0.68) between groups. In addition, IIV significantly predicted both intellectual functioning and academic achievement. These findings support the utility of examining IIV in the assessment of attentional ability in childhood epilepsy.