EEG coherence in unmedicated schizophrenic patients.

Area of Science:

• Neuroscience
• Psychiatry
• Biomedical Engineering

Background:

• Electroencephalogram (EEG) coherence studies in schizophrenia have yielded conflicting results, partly due to confounding factors like medication.
• Previous research using bipolar EEG recordings indicated higher coherence in medicated schizophrenic patients.

Purpose of the Study:

• To investigate EEG coherence in unmedicated schizophrenic patients, comparing them to affective disorder patients and normal controls.
• To determine if observed EEG coherence differences in schizophrenia are related to medication or reflect underlying cortical organization.

Main Methods:

• Bipolar EEG recordings were obtained from unmedicated schizophrenics (n=10), affective disorder patients (n=8), and controls (n=13) during resting and task conditions.
• Seven schizophrenic patients were reassessed after neuroleptic treatment.
• EEG coherence was analyzed in theta and alpha bands.

Main Results:

• Schizophrenic patients showed significantly higher interhemispheric and intrahemispheric coherence in the theta band.
• A trend towards higher intrahemispheric alpha coherence was observed in schizophrenics.
• Neuroleptic treatment improved clinical symptoms and increased spectral power but did not alter coherence values.

Conclusions:

• Increased EEG coherence in schizophrenics appears to reflect anomalous cortical organization, not medication effects or acute clinical states.
• Findings support the hypothesis of altered brain connectivity in schizophrenia.
• Bipolar EEG recordings provide a more reliable measure of coherence in psychiatric populations.