Brain grey matter abnormalities associated with myoclonic seizures

Abstract

Introduction. Epilepsy as a network disorder typically involves widespread abnormalities, existing evidence suggests that frontal lobe and thalamus are the key structures involved in generation of myoclonic seizures. Purpose. However, data indicating clear morphometric alterations of other grey matter structures in this seizure type is limited. Our purpose was to characterize the cortical and subcortical volumes in patients with myoclonic seizures. Material and methods. Cortical and subcortical grey matter volumes were extracted from 3T MRI scans across 40 patients (mean age ± standard deviation: 25±7 years; 14 males) with myoclonic seizures and 40 healthy subjects (23±5 years; 14 males, Table 1) by using FreeSurfer pipeline. Statistical maps were corrected by Monte Carlo permutation cluster analysis at a threshold of p<0.05 (Z=1.3). Results. A statistically significant difference of cortical volumes between patients and controls was found in: superior parietal, postcentral and fusiform of the left hemisphere; middle temporal of the right hemisphere and bilateral precentral, superior frontal and precuneus (Figure 1). Analysis of subcortical volumes revealed smaller volumes of bilateral thalamus in patients (right 7043.8921.8 / left 7697.91045.5 mm3) compared to controls (right 8148.6720.4 / left 9205.41151.4 mm3, p<0.05) (Figure 2) and reduced volumes of bilateral caudate in patients (right 3542.9598.1 / left 3536.6575.2 mm3) compared to controls (right 3817.4451.1 / left 3960.0438.9 mm3, p<0.05). Conclusions. These findings of reduced bilateral thalamus volumes as well as selected cortical volumes support the hypothesis of aberrant cortico-thalamic networks in epilepsy with myoclonic seizures.