Abstracts

Rationale: Children with severe epilepsy often have deficits in executive functioning. This is presumed to reflect dysfunction in frontal lobe circuits, but the relationship between executive functioning and brain structure has not been well studied. Cortical thickness analysis provides a promising new way to investigate grey matter thickness in a non-invasive manner using MRI technology. In a preliminary study, we investigated whether frontal grey thickness was related to executive functioning in children with focal epilepsy.Methods: Twenty three children with focal epilepsy were recruited from the pediatric neurology program at the Alberta Children s Hospital (mean age = 11.95 [4.0] years, range = 5.9 - 17.4 years, 10 boys, mean age at onset = 6.6 [4.6] years, current AEDs = 1.5 [0.7], prior AEDs = 1.4 [1.8]). All children underwent a clinical MRI with T1-weighted MP-RAGE sequence (TR = 2400 msec, TE = 4.5 msec, voxels = 1 mm³). Cortical reconstruction was performed using Freesurfer. Executive functioning was measured using the Behavior Rating Inventory of Executive Function (BRIEF), which measures overall executive functioning [Global Executive Composite (GEC)], as well as subcomponents of executive functioning [Metacognition (MC) and Behavioral Inhibition (BI)]. Partial correlations controlling for age were used.Results: Poorer executive functioning was associated with reduced thickness in areas of the left but not right dorsolateral prefrontal cortex (caudal middle frontal, rs = -.40-.46, p < .05; paracentral, rs = -.38-.42, p = .05; precentral, rs = -.48-.50, p < .05), for GEC, BI, and MC. Executive functioning as measured by GEC, BI or MC was not related to temporal lobe cortical thickness, with the exception of left superior temporal sulcus and GEC (r = -.42, p = .05).Conclusions: Reduced cortical thickness in the left frontal areas appears to be related to poorer executive functioning in children with focal epilepsy. These analyses provide preliminary data that may provide insights into the relationships between cognitive function and underlying grey matter structures in children with epilepsy.