Networks involved in seizure initiation. A reading epilepsy case studied with EEG-fMRI and MEG.

OBJECTIVE: To define the ictal cortical/subcortical network of reading-induced seizures.

METHODS: We analyzed ictal magnetoencephalography (MEG) and EEG-correlated fMRI (EEG-fMRI) data in a unique patient with reading epilepsy (RE) affected by frequent perioral reflex myocloni triggered by reading silently.

RESULTS: Ictal MEG corroborated EEG localization and revealed activity extending precentrally into Brodmann area (BA) 6. fMRI blood oxygen level-dependent (BOLD) signal changes in the left deep piriform cortex (PFC) and left BA6 preceded seizures and occurred before BOLD changes were observed in thalamus and right inferior frontal gyrus (BA44). Dynamic causal modeling provided evidence of a causal link between hemodynamic changes in the left PFC and reading-evoked seizures.

CONCLUSION: Our findings support the important role of deep cortical and subcortical structures, in particular the frontal PFC, as key regions in initiating and modulating seizure activity. In our patient with RE, BA6 appeared to be the area linking cognitive activation and seizure activity.