Frontal lobe epilepsy (FLE) is the second most common type of the localization-related epilepsies and its average age at onset ranges from 4 to 8 years (Manford et al., 1992; Braakman et al., 2011). FLE in children is frequently complicated by cognitive impairment, but this cognitive impairment shows strong interindividual variability (Braakman et al., 2011). Cognitive impairment generally comprises attention deficits and impaired executive functioning. In addition, a decline in intelligence quotient (IQ) scores, language impairment, and memory deficits have been described in children with FLE (Prévost et al., 2006; Braakman et al., 2011). Therefore, FLE does not impact on one specific function but on a broad range of cognitive domains, which frequently results in educational problems and the need for special education (Braakman et al., 2011, 2012). The etiology of cognitive deficits in children with FLE is unknown and correlations with clinical epilepsy characteristics, including age at seizure onset and seizure frequency, remain inconclusive (Braakman et al., 2011, 2012).
With functional MRI (fMRI) techniques, the functional brain organization can be investigated. Functional network changes have been observed in adult patients with localization-related epilepsy of unknown cause complicated by language impairment (Vlooswijk et al., 2010). Because cognitive impairment is already present early in the course of FLE (Prévost et al., 2006), we investigated correlations between cognitive impairment and brain organization in childhood with a focus on the role of the frontal lobe. Recently, we revealed whole-brain resting-state network abnormalities in the same cohort of children with FLE using graph theory (Vaessen et al., 2012). The current research work focuses on the specific role of the frontal lobe during verbal working memory processing. Our research questions were whether fMRI activation and connectivity results differ between children with FLE compared to healthy controls, and, if so, whether these differences relate to the cognitive impairment. In addition, we investigated whether in our patient cohort clinical epilepsy characteristics could be identified that are related to fMRI changes associated with cognitive impairment.