Abstract
Electroencephalography (EEG) based biomarkers have been shown to correlated with the presence of psychotic disorders. Increased delta and decreased alpha power in psychosis indicate an abnormal arousal state. We investigated brain activity across the basic EEG frequencies and also dynamic functional connectivity of both intra and cross-frequency coupling that could reveal a neurophysiological biomarker linked to an aberrant modulating role of alpha frequency in adolescents with schizophrenia spectrum disorders (SSDs).A dynamic functional connectivity graph (DFCG) has been estimated using the imaginary part of phase lag value (iPLV) and correlation of the envelope (corrEnv). We analyzed DFCG profiles of electroencephalographic resting state (eyes closed) recordings of healthy controls (HC) (n=39) and SSDs subjects (n=45) in basic frequency bands {δ,θ,α1212,γ}. In our analysis, we incorporated both intra and cross-frequency coupling modes. Adopting our recent Dominant Coupling Mode (DoCM) model leads to the construction of an integrated DFCG (iDFCG) that encapsulates the functional strength and the DoCM of every pair of brain areas.We revealed significantly higher ratios of delta/alpha1,2 power spectrum in SSDs subjects versus HC. The probability distribution (PD) of amplitude driven DoCM mediated by alpha frequency differentiated SSDs from HC with absolute accuracy (100%). The network Flexibility Index (FI) was significantly lower for subjects with SSDs compared to the HC group.Our analysis supports a central role of alpha frequency alterations in the neurophysiological mechanisms of SSDs. Currents findings open up new diagnostic pathways to clinical detection of SSDs and supports the design of rational neurofeedback training.Highlights: Ratios of delta/alpha1,2 relative power spectrum were significant higher in SSDs subjects compared to HC Probability distribution (PD) of amplitude driven DoCM mediated by alpha frequency differentiated SSDs from HC with 100% Network Flexibility index (FI) was significant lower for subjects with SSDs compared to HC group.