Cerebral white matter integrity in children with active versus remitted epilepsy 5 years after diagnosis

Abstract

Diffusion tensor imaging (DTI) studies have reported white matter abnormalities in childhood-onset epilepsy, but the mechanisms and timing underlying these abnormalities, and their resolution, are not well understood. This study examined white matter integrity in children with active versus remitted epilepsy. Tract-based spatial statistics (TBSS) was used to examine whole-brain DTI indices of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) in 20 children with epilepsy 5-6 years after diagnosis, compared to 29 healthy controls. To determine the status of white matter following cessation of seizures, participants with epilepsy were classified as active versus remitted and comparisons included: (1) controls versus all children with epilepsy, (2) controls versus children with remitted seizures, (3) controls versus children with active seizures, and (4) children with active versus remitted epilepsy. In the active compared to remitted epilepsy group, significantly higher FA and lower MD, AD and RD values were dispersed in the internal capsule, cingulum, body of the corpus callosum, superior corona radiata and superior fronto-occipital fasciculus. Similar differences were found between the active epilepsy and the control group. There were no significant differences between the remitted epilepsy and control groups. Children with active epilepsy differed in white matter integrity compared to children with remitted epilepsy and healthy controls. It remains to be determined whether these findings represent the outcomes of seizure remission versus an initial biomarker for those children who will ultimately have intractable epilepsy.