Electroencephalographic Microstates in Schizophrenia and Bipolar Disorder

Area of Science:

• Neuroscience
• Psychiatry
• Biomarkers

Background:

• Schizophrenia (SCH) and bipolar disorder (BD) share symptoms, cognitive deficits, and altered brain connectivity.
• Electroencephalography (EEG) microstates represent fundamental brain electrical activity patterns.
• Microstates are hypothesized to reflect underlying mental states and neural dynamics.

Purpose of the Study:

• To investigate EEG microstates as potential biomarkers for differentiating schizophrenia from bipolar disorder.
• To provide an electrophysiological explanation for brain dysfunction in SCH and BD patients.
• To analyze group differences in microstate parameters (duration, coverage, occurrence, transition probability).

Main Methods:

• Resting-state EEG data were analyzed from 20 SCH patients, 26 BD patients, and 35 healthy controls (HCs).
• Four distinct microstate maps (A-D) were identified using global microstate analysis.
• Group differences in microstate duration, coverage, occurrence, and transition probabilities were assessed.

Main Results:

• Microstate analysis revealed distinct patterns across SCH, BD, and HC groups.
• BD patients showed increased presence of microstate B.
• SCH patients exhibited decreased presence of microstates A and B, increased C, and decreased D.
• BD patients had more frequent transitions between microstates A and B, and less frequent transitions between C and D compared to SCH and HCs.

Conclusions:

• Abnormal microstate features (A, B) were identified in BD patients.
• SCH patients displayed abnormalities across all four microstates (A, B, C, D).
• These microstate abnormalities suggest potential differences in neural resource allocation and state transitions between SCH and BD patients.