EPILEPSY

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In selected patients with intractable temporal lobe epilepsy, (epilepsies which are poorly controlled by medication), surgery can provide an effective therapeutic option. However, the selection of a patient for surgery is typically limited by the diagnostic procedures available to identify the epileptic focus. The procedures for lateralizing the focus include routine EEG and Video-EEG monitoring, magnetic resonance imaging (MRI), positron emission tomography (PET) and the intracranial placement of EEG electrodes by surgery. The goals of this study are to 1) evaluate the biochemical changes associated with temporal lobe epilepsy and 2) evaluate the sensitivity and specificity of NMR Spectroscopic Imaging (NMRSI) in localizing and lateralizing epileptogenic tissue in patients with intractable epilepsy. Data will be collected using a 4T whole-body NMR system. During the acquisitions, no specific actions are required on part of the patient other than to remain still. The chemical composition data will be analyzed for alterations from control values (obtained in healthy individuals) to identify regions with metabolic abnormalities including: decreases in N-acetyl aspartate, (a marker of neuronal dysfunction/loss); increases in total creatine (marker for increased glia to neuron ratios), increases in glutamate (the primary excitatory neurotransmitter) decreases in phophocreatine and ATP (cerebral energy stores) and decreased oxidative metabolism (rate of incorporations of 13C labeled glucose into glutamate). This data will be correlated with available routine clinical data (EEG, neuro-psychological testing, video-EEG monitoring and surgical outcome) to assess the sensitivity and specificity. If successful, this methodology may replace the need for carrying out invasive intracranial electrode studies in particularly complex studies. This in turn would provide a more cost effective and safer method for planning in temporal lobe surgery.