The Medical Neurology Branch, NINCDS, 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, a CSL-designed computer system that detects epileptiform discharges from the eEG and MEG signals in real-time was placed into clinical operation. This system has been implemented with a number of detection algorithms, including both those developed by CSL and some selected from the published literature, and a variety of options fore configuring these algorithms allowing the medical staff to choose the optimal method for a given patient. The system provides a real-time display of the signals showing where an event is detected and allows the neurologists to manually save both epileptiform discharges and longer seizure activity. Work began on the clinical evaluation of this system. Development of three- dimensional displays of a patient's head using the digitized outline of the head along with anatomical data obtained from computed tomography and magnetic resonance imaging scans continued using the Mayo Foundation ANALYZE software package on a UNIX workstation. Neurologists will view thee displays to determine where epileptic sources are located relative to actual brain anatomy. In the coming year, CSL will perform a comprehensive clinical evaluation of the real-time detection system and compare its performance to that of a new commercial system that uses an algorithm not available on the CSL system. Work will continue on the development of the three-dimensional anatomical displays.
