UBC Theses and Dissertations
Development of a real-time, microprocessor based, detector of epileptiform activity in EEG Panych, Lawrence Patrick
This is an experimental thesis describing the development of a monitor for the detection of epileptic activity in the human EEG. The monitor, built around an Apple II Plus microcomputer system, has the capability for real-time detection of seizure activity and interictal transients (spikes and sharp waves or SSW) on 16 EEG channels. A dynamic graphics display symbolically presents to the user a running sum of the SSW detected during a monitoring session. A report is produced at the end of the session which includes a summary of SSW detections and the on-line phase reversal processing of the transients. An automatic seizure detection by the monitor will trigger the marking of the location of seizure records on magnetic EEG recording devices. Of significance is a theoretical explanation which shows why a simple slope detector performs as well as a complicated parametric transient detector. The real-time capability of the slope detector makes it superior in practical applications. Statistical detection theory is applied to the problem of EEG epileptic transient detection and the computer model which calculates a theoretical performance factor for detectors is described. Simple algorithms for selecting epileptic transients based on morphological considerations and methods of artifact rejection are presented. The monitor was evaluated in a clinical seizure investigation unit at the University of British Columbia. Clinically significant seizures were detected over a six month period with a very high success rate. In the cases of patients with focal epilepsies, predictions of focus locations by the device agreed with the neurological diagnoses of the patients.