Abstracts

Rationale: Visual assessment of structural MRI is, by definition, normal in patients with juvenile myoclonic epilepsy (JME), a major subsyndrome of idiopathic generalized epilepsy. However, recent quantitative MRI studies have shown structural abnormalities in frontal and thalamic grey matter (GM) in JME. In the present study, we addressed the issue of whether diffusion tensor MRI (DTI) can detect white matter abnormalities in patients with JME. We also performed several neuropsychological tests to evaluate frontal lobe dysfunctions in JME patients as compared to control subjects. Methods: Fifteen JME patients and 21 control subjects matched for age and sex underwent whole head DTI on a 3T MR scanner. After creating a study-specific fractional anisotropy (FA) and mean diffusivity (MD) maps, voxel-wise comparisons of the FA and MD maps were made between patients and controls by using statistical parametric mapping (SPM) analysis (thresholded at FDR-corrected P < 0.05 on a voxel level). Neuropsychological tests examining frontal executive functions were also performed and compared between patients and controls. Results: SPM analyses showed FA reductions in bilateral internal capsule (including parts of the thalamus), corpus callosum, cingulum, and frontal white matter, and MD increases in bilateral thalamus, basal ganglia, cingulum, and frontal lobe in JME patients compared to controls (FDR-corrected P < 0.05). Compared to controls, JME patients showed impairment in frontal executive functions as assessed by trail making, stroop, word list generation, and digit span tests (all P < 0.05, two-sample t-test). Conclusions: Our findings of white matter integrity disruptions as demonstrated by FA reductions and MD increases as well as frontal executive dysfunctions on neuropsychological tests support the hypothesis of the thalamo-frontal network abnormalities in JME.