The Medical Neurology Branch, NINCDS, the Biomedical Engineering and Instrumentation Branch, DRS, and the Computer Systems Laboratory, DCRT are collaborating on a research project to noninvasively localize epileptic discharge sources within the human brain by using neuromagnetic recording in conjunction with conventional electroencephalogram (EEG) recording. Many patients with seizure disorders exhibit low-level cellular discharges between seizures, indicated by interictal spikes or sharp waves in their EEG and magnetoencephalogram (MEG) recordings. This project involves the development of computer techniques for automating and enhancing the procedure that is presently used by NINCDS neurologists to determine the intracranial locations of the sources of epileptiform discharges in patients with epilepsy. During the past year, an algorithm that automatically detects the epileptiform discharges from the EEG and MEG signals was developed and tested with siqnals obtained from epileptic patients. Three- dimensional displays of the outline of the patient's head showing where the magnetometer had been positioned during previous measurement sessions were also developed so that the neurologists can plan sensor positions for future sessions. A Signal Processing Workstation was added to the system and will be used in the future to perform various signal processing tasks. In the coming year, the detection program will be tested with more patient data and implemented on the workstation to perform real- time detection. Methods for classifying the detected epileptiform discharges into types based on their morphology using correlation techniques will be developed. Anatomical data obtained from CT and MRI scans will be intergrated with the three-dimensional displays of the outline of the patient's head so that epileptic sources can be represented relative to actual brain anatomy.
