Widespread cortical morphologic changes in juvenile myoclonic epilepsy: evidence from structural MRI

Abstract

Purpose: Atypical morphology of the surface of the cerebral cortex may be related to abnormal cortical folding (gyrification) and therefore may indicate underlying malformations of cortical development (MCDs). Using magnetic resonance imaging (MRI)-based analysis, we examined cortical morphology in patients with juvenile myoclonic epilepsy (JME).

Methods: MRI data was collected for 24 patients with JME and 40 demographically matched healthy controls. FreeSurfer, an automated cortical surface reconstruction method, was applied to compare cortical morphology between patients and controls. Areas of anomalous cortical morphology were defined as regions of interest (ROIs) to contrast regional cortical parameters, such as surface area, average thickness, and mean curvature between patients and controls.

Key findings: In patients with JME, changes to cortical morphology were detected in several regions. In the left hemisphere, these were in insular and cingulate cortices, occipital pole, and middle temporal and fusiform gyri. In the right hemisphere, changes were detected in insular cortex, inferior temporal gyrus, and precuneus. Further analysis of ROIs revealed that these changes are related to differences in surface area rather than average cortical thickness. In addition, mean curvature abnormalities were detected in the insula bilaterally, the left cingulate cortex, and right inferior temporal gyrus.

Significance: The morphologic findings in this study suggest that structural abnormalities in JME extend beyond mesial frontal lobe regions of the brain. These may be indicative of areas of subtle cortical folding abnormality related to early disruption of cortical development.