Intracranial electroencephalography (EEG) remains the "gold standard" for the definition of seizure origin, the so-called seizure onset zone (SOZ). It measures directly neuronal activity with an excellent temporal resolution, but with a spatial resolution that depends on a priori clinical hypothesis. The method is very specific but invasive and hence can be used in a limited number of patients with severe intractable focal epilepsies. EEG-functional MRI (EEG/fMRI) is another method to evaluate epileptic activity (EA) generation. It measures the blood oxygen level-dependent (or BOLD) changes related to an epileptic event, reflecting indirectly the neuronal activity through metabolic and hemodynamic modifications. EEG/fMRI measures the EA with a good temporal and spatial resolution providing that the electrophysiologic signal is detectable, but EEG/fMRI is noninvasive and easily repeatable.
展开▼
