Epilepsy is the most common chronic neurological disorder in the world, affecting more than 50 million people worldwide. Approximately 35% of patients with epilepsy are refractory to all available antiepileptic drugs. Drug-resistant epilepsies are often partial or focal. Patients with drug-resistant focal epilepsy suffer from an increased risk of death, primarily due to seizure-related fatalities, in comparison with the general population. The only therapeutic option for this form of epilepsy is the surgical removal of the region of the brain responsible for seizures, called the epileptogenic zone (EZ). This requires the precise localization of the EZ based on a comprehensive pre-surgical evaluation of patients.
Today the gold standard for localizing the EZ and validating a non-invasive technique for localization of the EZ remains intracerebral stereo-EEG (stereo-electroencephalography or SEEG) recordings of spontaneous seizures. The implementation strategy of the intracerebral depth electrodes is guided by clinical and neuroimaging data, including anatomical Magnetic Resonance Imaging (MRI), Positron Emission Tomography (PET) with FDG (fluoro-Deoxy-Glucose) and MagnetoEncephaloGraphy (MEG). Although the contribution of each technique in the pre-surgical localization of the EZ has already been shown, no wide-scale study has examined the cumulative contribution of these three techniques.
Primary Outcome Measures:
- Localizing value of MEG, FDG-PET and MRI for the determination of the Epileptogenic Zone defined by SEEG recordings [ Time Frame: 180 days ] [ Designated as safety issue: No ]
Pathological volumes defined by multimodal imaging (MEG, FDG-PET and MRI) will be compared to the topography of the EZ defined by SEEG recordings.
For each patient, we will sum the total number of intracerebral depth electrodes included in the EZ. Then, for each functional volume obtained from multimodal data fusion, we will count the total number of electrodes in the latter (Vol elec_tot) and the number of electrodes included in the EZ (Vol elec_ze).
Secondary Outcome Measures:
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| Estimated Primary Completion Date:
||November 2012 (Final data collection date for primary outcome measure)
The purpose of this study is (i) to evaluate rigorously the diagnostic value of multimodal imaging for non-invasive localization of the EZ and (ii) to better target the indications for intracerebral recordings (SEEG).