Myoclonic seizures and the frontal lobe

Abstract

Background: Recent studies suggest a presumed focal origin of myoclonic seizures. In the current study, we aimed to appreciate the cortical sources of the interictal generalized discharges examining patients with myoclonic seizures using high-density EEG (HD-EEG). Material and methods: In this study, 40 patients (mean age ± standard deviation: 25 ± 7 years; 14 males) with myoclonic seizures were included. All participants were scanned with a 3T MRI machine and 256-channel EEG recording. For spatio-temporal source reconstruction, LORETA (low resolution brain electromagnetic tomography) solution was applied. Results: In all 40 patients, the electric sources of interictal generalized discharges were detected in the frontal lobe. In 17 (42%) patients the origin of discharges was in the middle frontal gyrus (Brodmann Area (BA)-9 in 7 patients, BA-10 in 3 patients, BA-6 in 4 patients and BA-8 in 3 patients). In 13 (33%) patients the origin was identified in the superior frontal gyrus (BA-6 in 9 patients, BA-10 in 3 patients and BA-8 in 1 patient). In 10 (25%) patients the source was localized in the inferior frontal gyrus (BA-11 orbital part in 8 patients and BA-46 in 2 patients). Conclusions: HD-EEG data suggest that myoclonic seizures are not truly generalized seizures in the sense of global activation of the cortex, but rather restricted networks of cortex are involved in the discharges and primarily recruit the frontal lobe networks.