EEG-fMRI study of the ictal and interictal epileptic activity in patients with eyelid myoclonia with absences.

PURPOSE: To investigate the blood oxygenation level-dependent (BOLD) signal changes correlated with ictal and interictal epileptic discharges using electroencephalography-correlated functional magnetic resonance imaging (EEG-fMRI) in patients with eyelid myoclonia with absences (EMA) and then to explore the pathophysiological mechanisms of epileptic discharges and their effect on brain function.

METHODS

Four patients with EMA were investigated through the method of EEG-fMRI. The characteristics of BOLD signal changes linked to ictal and interictal epileptic discharges under different states of consciousness were explored.

RESULTS

Seven sessions of EEG-fMRI scanning in the four patients were obtained. The main regions of activation included thalamus, mesial frontal cortex, middle parietal lobe, temporal lobe, insula, midline structures, and cerebellum. Deactivations were mainly in the anterior frontal lobe, posterior parietal lobe, and posterior cingulate gyrus. Thalamic BOLD change was predominantly activation in most of our cases. The distribution of activation associated with ictal epileptic discharges was wider, and the distribution of deactivation was closer to pericortex compared with the BOLD change linked with interictal epileptic discharges.

CONCLUSIONS

The activation in the thalamus may be associated with generalized spike wave in EMA; the combination of different patterns of activation with consistent pattern of deactivations ("default" pattern) in patients with EMA may prognosticate different states of consciousness in response to ictal and interictal epileptic discharges.