Abstracts

Rationale: Benign epilepsy with centrotemporal spikes (BECTS) is a transient epilepsy syndrome in which school age children suffer from seizures characterized by initial face or tongue sensorimotor symptoms. Although EEG features follow an autosomal dominant inheritance pattern, there is low penetrance of the seizure trait in BECTS, so other factors must impact seizure risk. Stereotyped seizure semiology and interictal epileptiform activity localize to the pre- and postcentral gyri (perirolandic cortex) in these children. Because white matter networks typically mature during the period that children with BECTS have seizures, we sought to evaluate whether subtle alterations in white matter integrity in the perirolandic region is altered in children with BECTS and whether these changes correlate with disease course. Methods: 17 children with BECTS (13 M, 4 F, ages 8-15) and 8 healthy controls (3 M, 5 F, ages 7-14) were recruited. High-resolution MRI data were acquired on a 3T Magnetom Prisma scanner using a 64-channel head coil with the following sequences: DTI (64 encoding directions, TE = 82 ms, TR = 8080 ms, flip angle = 90°, b = 2000 s/mm2, voxel size = 2 × 2 × 2 mm); MEMPRAGE (TE = 1.74 ms, TR = 2530 ms, flip angle = 7°, voxel size = 1 × 1 × 1 mm). Eddy current distortion, field inhomogeneities, and head motion were corrected using FSL-FMRIB. FSL’s DTIFIT was used to compute a diffusion tensor model at each voxel. Pre- and postcentral gyri were defined using FSL-FMRIB’s Automated Segmentation Tool. Cortical labels were then sunk 1 mm into white matter to define perirolandic regions of interest (ROIs). Mean axial diffusivity (AD) was computed for each ROI for each subject and compared to group status and time from seizure using logistic and linear regression models, controlling for age. Results: Mean axial diffusivity in the white matter adjacent to the precentral (p=0.035) and postcentral (p=0.057) gyri both predict subject group. Mean axial diffusivity in the white matter adjacent to the precentral gyrus significantly correlates with the number of months since last known seizure (p=0.02); a similar trend was seen in white matter adjacent to the postcentral gyrus (p=0.10). The white matter maturation patterns in the peri-rolandic regions followed opposite trajectories, where the AD in the white matter adjacent to the precentral gyrus had a negative correlation with time from last seizure, and the AD in the white matter adjacent to the postcentral gyrus had a positive correlation with time from last seizure. Conclusions: This age-specific epilepsy syndrome provides a new model of structural factors that may contribute to seizure risk. Here, targeted measures of axial diffusivity in white matter adjacent to the seizure onset zone correlate both with the presence of epilepsy and time from most recent seizure. Funding: NINDS K23 NS092923