Computer Analysis of Serial Electroencephalograms from Patients with Cerebrovascular Accidents
Date of Award
Dissertation - Restricted
Doctor of Philosophy (PhD)
The evaluation of the clinical electroencephalogram (EEG) is routinely done using visual examination methods. Period analysis of the EEG has been predominantly a research tool. This dissertation describes the results of using digital computer period analysis on serial EEGs from patients with cerebrovascular accidents (CVA). It was the primary goal of this research to develop a method of extracting information from serially recorded EEGs from CVA patients which might be significant with respect to these patients' prognoses. To that end, twenty-six CVA patients and twenty-six matched controls were serially tested. Zero-cross analysis techniques were used to compute the activity in various frequency bands. An analysis of the time-varying properties of the EEG from control subjects was undertaken. Using the mean value and the time interval. between successive zero crossings, the EEG was found to be stationary for epochs shorter than twelve seconds. Based upon the mean value only, the EEG was found to be stationary for epochs up to sixty-four seconds nearly 65 percent of the time at the p=0.05 level...