Evaluation of white matter differences in epilepsy using tract based spatial statistics method

Juvenile myoclonic epilepsy (JME) is known to cause changes in brain structure and white matter integrity. Diffusion tensor imaging, one of the neuroimaging methods, is applied in order to detect microstructural changes caused by the disease. Tract Based Spatial Statistics (TBSS) is one of the preferred methods for voxel-based analysis of diffusion data and for intergroup comparison. The aim of this study is to determine structural white matter changes in patients with JME and the photosensitive and nonphotosensitive subgroups using the TBSS method. The study included data from 16 photosensitive JME patients, 15 nonphotosensitive patients with JME, and 41 healthy participants. The mean fractional anisotropy (FA) values of these groups were calculated, and comparisons were made via the TBSS method over FA values in the whole brain and 81 regions of interest (ROI) obtained from the Johns Hopkins University White Matter Atlas. In the whole brain TBSS analysis, no significant difference in FA values was observed in the pairwise comparisons of JME patient group, and subgroups with healthy controls, and in the comparison between JME subgroups. In ROI-based TBSS analysis, an increase was found in FA values of the right anterior corona radiata and left corticospinal tract pathways in the JME patient group compared to the healthy control group. In the comparison of photosensitive JME patients with healthy controls, FA increase was observed in the bilateral anterior corona radiata region; while FA increase was found in the bilateral corticospinal pathway in the comparison of non-photosensitive JME patients with healthy controls. Moreover, in subgroup comparison, an increase was noted in the FA values of photosensitive patients with JME in the corpus callosum genu region compared to the non-photosensitive patients with JME. The results emphasize that there are white matter changes especially in the thalamofrontal pathways in JME. Keywords: Juvenile Myoclonic Epilepsy, Photosensitivity, Diffusion Tensor Imaging, Tract Based Spatial Statistics, FSL