To assess exercise effects on white matter integrity and neurite morphology in adults with idiopathic generalized epilepsy (IGE).

While exercise is known to be beneficial for overall physical and cognitive well-being, its effects in people with epilepsy are understudied. Further, it is unclear whether a 6-week exercise intervention can induce changes in white matter and neurite morphology in the brain.

Seven adults with idiopathic generalized epilepsy (IGE) underwent a 6-week exercise intervention (18 sessions total) of combined endurance and resistance training (IGE-Ex), and 7 were no-exercise controls (IGE-NoEx). Both groups underwent baseline 3T MRI scan and returned after 6 weeks for follow-up. An anatomical MRI and a high angular resolution imaging diffusion protocol were performed. MRI data were analyzed using AFNI, MATLAB, NODDI Toolbox, and FSL programs. The following diffusion MRI metrics were obtained: mean diffusivity (MD), fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), orientation dispersion index (ODI), free water volume fraction (V-ISO), and intracellular volume fraction (ICVF). Linear mixed-effects models were used to assess group by visit interactions. Signal extractions were performed and plotted to interpret any interactions.

We observed significant group by visit interactions that overlapped for MD, RD and ICVF in clusters located within the left superior longitudinal fasciculus and left corticospinal tract (voxelwise p=0.01, cluster threshold of 123 voxels). Signal extraction from the clusters for each of these diffusion MRI metrics revealed that IGE-Ex had decreased MD and RD and increased ICVF, while IGE-NoEx had increased MD and RD and decreased ICVF in these regions.

Increased MD and RD are implicated in white matter damage, while decreased ICVF suggests decreased myelin. Our preliminary data show that a 6-week exercise intervention may prevent and potentially reverse myelin-specific white matter degradation in adults with IGE.