Abstracts

Rationale: Juvenile myoclonic epilepsy (JME) is a common genetic generalized epilepsy accounting for approximately 18% of all genetic generalized epilepsies and 4-6% of all epilepsies. It is a heterogeneous condition that can be broken into four subsyndromes. The two most common subsyndromes consist of patients with myoclonic and generalized tonic-clonic seizures and patients with absence, myoclonic, and generalized tonic-clonic seizures. With recent advances in functional neuroimaging, there has been an increase in the understanding of the pathophysiology underlying JME, but more studies are needed to provide insight into the pathogenesis of this condition. Methods: Two patients with a clinical diagnosis of JME completed a brief seizure history questionnaire (Table 1 - patient's epilepsy history). Two resting-state neuroimaging studies were performed: 1) 148 channel MEG combined with 32 EEG, 2) fMRI. MEG and EEG were reviewed for interictal and ictal patterns of epilepsy. Equivalent current dipoles (ECD) and Coherence analysis were performed on the MEG data, results were coregistered and displayed on the patient's MRI. Coherence is a measure of oscillating neuronal activity and their synchronicity across the cortex, which defines the neuronal network connectivity. fMRI was performed on each patient using a 3T MRI system. Diffusion Tensor imaging (DTI) analysis was used to measure and evaluate the connectivity between 9 regions of interest by calculating power spectra and coherence measurements. Results: Both patients demonstrated a normal awake posterior dominant rhythm as well as physiologic sleep architecture seen in MEG and EEG. Patient 1 had multiple generalized polyspike-and-wave discharges present on both EEG and MEG. Four of the five interictal events mapped to the right middle frontal gyrus (MFG), and one mapped to the left MFG. MEG Coherence analysis revealed scattered areas of high coherence within the right and left postcentral gyrus, precentral gyrus, as well as the left supramarginal gyrus, and right superior frontal gyrus. Patient 2 had multiple generalized spike and polyspike-and-wave discharges present on both EEG and MEG. Five interictal spike events mapped to the right precentral gyrus, MFG, and right and left inferior frontal gyri. MEG Coherence analysis showed high coherence within the left fusiform gyrus. fMRI results for Patient 1 displayed more consistent differences from controls than Patient 2. The bilateral prefrontal cortices and middle temporal gyrus showed stronger connectivity in Patient 1 and less connectivity with Patient 2. Conclusions: Two patients with a clinical diagnosis of JME had a MEG and fMRI that demonstrated different imaging patterns. Although other reports have found involvement of the prefrontal cortex in patients with JME, no clear epileptic network was identified in these two patients. However, each patient showed different patterns of neuronal oscillations with MEG coherence as well as different connectivity patterns on fMRI. These findings may suggest different subsyndromes of JME have different epileptic networks.