A Nonlinear Study of EEG in Patients with Affective Disorder

Abstract

The aim of this study is to investigate the nonlinear characteristics of electroencephalogram (EEG) in patients with affective disorder via higher-order statistics (HOS). The Bispectral Index (BI) is proposed as a nonlinear quantification to identify if BI could be used as a discriminating statistics to demonstrate the nonlinearity in the EEG. The difference between the bicoherece patterns of EEG in healthy subjects and patients with affective disorder is expected to reflect some mechanism of the underlying brain wave based on the hypothesis that nonlinearity may manifest the mechanistic difference. Both depressives and maniacs are investigated and compared with normal controls. The results indicate that the nonlinear analysis based on BI can provide the means of investigating the brain electrical activities of patients with affective disorder.