Simultaneous electroencephalography and functional magnetic resonance imaging Part of clinical diagnostics?

EEG-fMRI has been used in epilepsy as a tool to indentify epileptic networks involved in the generation of spikes and seizures. The method is based on the measure of blood flow changes and allows the high temporal resolution of EEG to be combined with the high spatial resolution of MRI to evaluate brain networks involved in generating intrinsic brain signals. The main focus of research in generalized epilepsies is the understanding of underlying mechanisms, while EEG-fMRI in focal epilepsies has also been evaluated as a method for focus localization in presurgical epilepsy. Despite its extensive use over recent years, EEG-fMRI in epilepsy is still not established as a routine clinical tool, as it faces many methodological challenges which complicate its interpretation. In some patients the sensitivity of the method is low due to a lack of sufficient number of interictal spikes; the correct manner for statistical analysis as well as thresholding are still being debated. The present review gives a short overview of clinical applications of EEG-fMRI in epilepsy and discusses in detail new developments in the field which may allow methodological challenges to be overcome in the future.