Clinical application of EEG topography in cerebral ischemia: detection of functional reversibility and hemodynamics

To detect the functional reversibility and hemodynamic process in cerebral ischemia, the EEG topography cased on % time and amplitude was applied. % time and amplitude were obtained by the wave-form recognition method/EEGs were recorded under the resting state and during drug-induced conditions in 18 patients with steno-occlusion of main cerebral artery. The type of ischemic attack was TIA in 2 patients, RIND in 4, minor stroke in 7 and major stroke in 5. Six of 11 patients showed the improvement of EEG under induced hypertension. Four of those 6 patients were operated on ECIC bypass surgery, and all of them showed the improvement of clinical and EEG findings postoperatively. Twelve patients showed the deterioration of EEG under induced hypotension. Eight of them were operated on ECIC bypass surgery, and none of them suffered from reattack of cerebral ischemia postoperatively. Those preoperative EEG changes were observed mainly on the EEG topography of % time. And, the analysis of the EEG topography of % time under drug-induced conditions was available to study the pathophysiology of cerebral ischemia for selecting the suitable treatment.