Local and Widely Distributed EEG Activity in Schizophrenia With Prevalence of Negative Symptoms

Abstract

We evaluated EEG frequency abnormalities in resting state (eyes closed and eyes open) EEG in a group of chronic schizophrenia patients as compared with healthy subjects. The study included 3 methods of analysis of deviation of EEG characteristics: genuine EEG, current source density (CSD), and group independent component (gIC). All 3 methods have shown that the EEG in schizophrenia patients is characterized by enhanced low-frequency (delta and theta) and high-frequency (beta) activity in comparison with the control group. However, the spatial pattern of differences was dependent on the type of method used. Comparative analysis has shown that increased EEG power in schizophrenia patients apparently concerns both widely spatially distributed components and local components of signal. Furthermore, the observed differences in the delta and theta range can be described mainly by the local components, and those in the beta range mostly by spatially widely distributed ones. The possible nature of the widely distributed activity is discussed.

Functional indexes of reactive cognitive control: ERPs in cued go/no‐go tasks

“…These components were obtained by application of ICA to the raw EEG fragments. The method is similar to that described previously (Grin-Yatsenko et al, 2017;Li, Ma, Lu, & Li, 2006), and has been compared to the electrooculographic regression technique by Tereshchenko, Ponomarev, Kropotov, and Muller (2009). In addition, epochs with excessive amplitude of filtered EEG and/or excessive faster and/or slower frequency activity were automatically marked and excluded from further analysis.…”

Deficit Versus Nondeficit Schizophrenia: An MEG-EEG Investigation of Resting State and Source Coherence—Preliminary Data

“…The observed differences were seen as spatially widely distributed generators. 15 Schizophrenia patients with EEGs characterized by augmented low-frequency power and diminished alpha-band power show more negative symptoms compared with schizophrenia patients without these EEG characteristics. 16 In another recent study, elevated right-frontal delta activity was shown to be uniquely associated with negative but not positive symptoms in schizophrenia patients.…”

“…The resting state EEG in unselected schizophrenia patients has been characterized by enhanced low-frequency (delta and theta) activity in comparison with healthy control subjects. 14,15 In addition, high-frequency (beta) activity was also shown to be enhanced in patients with schizophrenia compared with healthy controls. The observed differences were seen as spatially widely distributed generators.…”

“…6. Fast Fourier transform on artifact-free epochs (total length of about 5-7 minutes) to obtain spectral power (absolute and relative) at different bands (delta[1][2][3][4], theta[4][5][6][7][8], alpha[8][9][10][11][12], beta1[12][13][14][15][16][17][18][19][20], beta2[20][21][22][23][24][25][26][27][28][29][30], and gamma).…”

Alterations of Resting EEG in Hallucinating and Nonhallucinating Schizophrenia Patients

“…16,17 These frequency bands are generally abnormal in schizophrenia: A few meta-analyses show that delta and theta activity are increased, alpha activity is often increased but sometimes reported as decreased, and beta activity is reported to be increased equally as often as it is decreased. 18,19 Alpha asymmetry can index lateralization of alpha activity and can be a useful marker because of the left hemisphere abnormalities and interhemispheric deficits commonly seen in schizophrenia. 20,21 Inconsistencies in the literature of EEG band analysis are likely due to disease heterogeneity.…”