title: EEG coherence in unmedicated schizophrenic patients.
abstract: We have recently shown that electroencephalogram (EEG) coherence data recorded with common reference methods, including those obtained from schizophrenics, are confounded by power and phase effects. Three published reports using bipolar recordings found that EEG coherence was higher in schizophrenics; however, only medicated patients were studied. To extend these findings, we measured EEG coherence from bipolar EEG recordings in unmedicated schizophrenics (n = 10), affective disorder patients (n = 8), and normal controls (n = 13) during resting and task conditions. Seven schizophrenics were restudied after a period of neuroleptic treatment. Schizophrenics had higher across-task interhemispheric (p less than 0.05) and intrahemispheric (p less than 0.04) coherence in the theta band and tended to have higher intrahemispheric alpha coherence (p less than 0.08). Medication treatment was associated with clinical improvement and increases in spectral power, but not with changes in coherence values. These results confirm those obtained by earlier investigations and suggest that increased coherence reflects the presence of anomalous cortical organization in schizophrenics rather than medication effects or transient states related to acute clinical disturbance.
authors.affiliation: VA Medical Center, San Francisco, CA 94121.
authors.forename: E L
authors.initials: EL
authors.lastname: Merrin
authors.forename: T C
authors.initials: TC
authors.lastname: Floyd
authors.forename: G
authors.initials: G
authors.lastname: Fein
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001714:Bipolar Disorder / Q000503:physiopathology; D001921:Brain / Q000187:drug effects / Q000503:physiopathology*; D003344:Cortical Synchronization; D003866:Depressive Disorder / Q000503:physiopathology; D004569:Electroencephalography; D005071:Evoked Potentials / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D012559:Schizophrenia / Q000188:drug therapy / Q000503:physiopathology*; D012565:Schizophrenic Psychology
chemical_list: D014150:Antipsychotic Agents