Structural Brain Abnormalities in Juvenile Myoclonic Epilepsy Patients: Volumetry and Voxel-Based Morphometry

Abstract

ObjectiveWe aimed to find structural brain abnormalities in juvenile myoclonic epilepsy (JME) patients.Materials and MethodsThe volumes of the cerebrum, hippocampus and frontal lobe and the area of the corpus callosum's subdivisions were all semiautomatically measured, and then optimized voxel-based morphometry (VBM) was performed in 19 JME patients and 19 age/gender matched normal controls.ResultsThe rostrum and rostral body of the corpus callosum and the left hippocampus were significantly smaller than those of the normal controls, whereas the volume of the JME's left frontal lobe was significantly larger than that of the controls. The area of the rostral body had a significant positive correlation with the age of seizure onset (r = 0.56, p = 0.012), and the volume of the right frontal lobe had a significant negative correlation with the duration of disease (r = -0.51, p = 0.025). On the VBM, the gray matter concentration of the prefrontal lobe (bilateral gyri rectus, anterior orbital gyri, left anterior middle frontal gyrus and right anterior superior frontal gyrus) was decreased in the JME group (corrected p < 0.05).ConclusionThe JME patients showed complex structural abnormalities in the corpus callosum, frontal lobe and hippocampus, and also a decreased gray matter concentration of the prefrontal region, which all suggests there is an abnormal neural network in the JME brain.

Cortical thickness abnormality in juvenile myoclonic epilepsy

“…Some of brain regions with a reduced cortical thickness in the JME group showed a negative correlation between cortical thickness and disease duration. This finding is consistent with the negative correlation found between right frontal lobe volume and JME disease duration in our previous study [25]. In an interictal SPECT study on drug naïve JME patients, we also reported a negative correlation between regional cerebral blood flow (rCBF) and the disease duration in frontal cortices [26].…”

“…However, other studies by VBM failed to confirm this finding [1,25], and thus, the finding of increased GMC is still controversial.…”

“…However, recent two studies produced different findings. One study reported increased frontobasal volume [1], whereas the other showed decreased GMC of gyri rectus and anterior orbital gyri in JME patients [25]. Even though these studies used the same VBM method, the detail processes used, e.g., SPM version, modulated or unmodulated, grand mean scaling, absolute or relative thresholding, differed [10], and thus VBM results may have differed because of subject selection and methodological issues.…”

“…The horizontal thick line in the box represents a median value. The circle is a "mild" outlier, and asterisk is an "extreme" outlier rostral body of the corpus callosum and decreased GMC in the prefrontal area in JME patients [25]. A recent VBM study in idiopathic generalized epilepsy (IGE) patients with primary GTCS also reported reduced GMC in frontal and temporal cortices [3].…”

CBF changes in drug naive juvenile myoclonic epilepsy patients

“…On the contrary, another VBM study in JME patients showed decreased gray matter concentration in frontal lobe (bilateral gyri rectus, anterior orbital gyri, left anterior middle frontal gyrus, right anterior superior frontal gyrus) [41]. Magnetic resonance spectroscopy study reported low concentrations of thalamic N-acetylaspartate (NAA) in JME [4,30].…”