Abstracts

Rationale: Benign Childhood Epilepsy with Centro-Temporal Spikes (BECTS) is a common type of epilepsy in children. Recent concerns have been raised about whether BECTS is actually 'benign' in terms of cognitive development and brain structure. Intelligence test scores, in particular processing speed, have been linked to differences in brain volume in both healthy controls and patients with epilepsy. This study aims to (1) determine if differences in gray or white matter volume exist between children with BECTS and healthy controls; (2) use regression analysis to relate volumetric measurements to differences in processing speed. Methods: 24 patients with BECTS and 24 healthy controls (ages 5-12, mean age 9.2, 7 females per group) participated in the study. Patients and controls were administered the symbol search and coding subtests of the Wechsler Scale of Intelligence to assess general processing speed (PSI). For volumetric analysis, T1-weighted anatomical brain images were obtained on all participants. Images were segmented into gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) using a Voxel Based Morphometry (VBM) toolbox that is compatible with Statistical Parameter Mapping (SPM8) software for whole brain and anatomically defined regions of interest, for which the superior temporal gyrus was analyzed. The comparison in brain volume (whole brain as well as different tissue classes) between the two groups was then conducted using a two sample t-test. The relationship between brain volume and processing speed was determined using multiple regression analysis in SPSS software. Results: Whole brain segmentation analysis revealed BECTS patients had significantly more GM centered at Brodmann's area 22, in the left superior temporal gyrus (p< 0.0005). A negative relationship between processing speed and GM volume in the superior temporal gyrus was observed in BECTS patients but not in controls (r = -0.48, p< 0.05). There was a trend (P=0.07) toward lower PSI scores in children with BECTS (mean 98 +/- 3.2) as compared to controls (mean 105 +/- 2.8). Conclusions: Regional differences in GM volume exist between patients with BECTS and controls. Notably, the larger the superior temporal GM volume, the slower the processing speed was in patients but not in controls. The observed structural differences between BECTS patients and controls may provide new insights into differences in cognitive function.