Spectral and bispectral EEG analysis in acute unilateral ischemic stroke patients

Abstract

With the recent development of new mathematical theory and personal computer, the analysis in which nonlinear theory was introduced to biological signals such as EEG (electroencephalogram) became possible, and convenient statistical technique became applicable. With these methods, the characteristics of signals can be analyzed, which are difficult to be acquired by interpretation with visual judgement. The authors statistically analyzed the EEG data of acute ischemic stroke in twenty cases by using spectral and bispectral analyses. In the spectral analysis, most of patients with cortical infarct, especially MCA (middle cerebral artery) infarct, showed a decrease in high-frequency wave bands (alpha, beta and gamma) at the lesion side, and the bispectral analysis had a similar result. However, patients with brainstem infarct did not show a regular pattern.