EEG power, cordance and coherence differences between unipolar and bipolar depression

Area of Science:

• Neuroscience
• Psychiatry
• Biomarkers

Background:

• Distinguishing unipolar depression (UD) from bipolar depression (BD) is crucial to prevent misdiagnosis and ensure appropriate treatment.
• Electroencephalography (EEG) offers a potential method for identifying neurophysiological biomarkers to differentiate between UD and BD.

Purpose of the Study:

• To investigate group differences in EEG power, cordance, and coherence between patients with UD and BD.
• To identify potential EEG-based biomarkers for distinguishing between these two mood disorders.

Main Methods:

• Recruited 25 patients with BD and 56 patients with UD.
• Collected resting-state EEG data and sociodemographic/clinical variables.
• Analyzed data using multivariate and repeated measures analyses of variance.

Main Results:

• No significant differences were found in EEG absolute power or frontal asymmetry between UD and BD.
• Significant group differences emerged in right theta cordance (p=0.031).
• Bipolar depression patients showed greater central-temporal theta (p=0.003) and parietal-temporal alpha (p=0.007) and theta (p=0.001) coherence compared to UD patients.
• Reduced alpha coherence was observed in BD at right frontal-central (p=0.007) and central inter-hemispheric (p=0.019) regions.

Conclusions:

• EEG cordance and coherence values show potential for discriminating between UD and BD.
• Altered temporal synchronization in specific brain networks may be a distinguishing feature of BD compared to UD.