Decreased functional connectivity of EEG theta-frequency activity in first-episode, neuroleptic-naïve patients with schizophrenia: preliminary results.
We explored and refined the hypothesis that during a first episode of acute schizophrenia a disorganization of brain functioning is present. A novel EEG measure was introduced, Global Field Synchronization (GFS), that estimates functional connectivity of brain processes in different EEG frequency bands. The measure was applied to EEG's from 11 never-treated, first-episode, young patients with an acute, positive, schizophrenic symptomatology and from 19 controls, residing in Bern, Switzerland. In comparison to age- and sex- matched controls, patients had significantly decreased GFS in the theta EEG frequency band, indicating a loosened functional connectivity of processes in this frequency. The result was confirmed in an independent, comparable patient group from Osaka, Japan (9 patients and 9 controls), thus making a total of 20 analyzed patients. Previous EEG research in healthy, awake subjects indicated a positive correlation of theta activity with memory functions. Thus, our result suggests a loss of mutual interdependence of memory functions in patients with acute schizophrenia, which agrees well with previous reports of working memory dysfunction in schizophrenia.
Koenig
T
T
University Hospital of Clinical Psychiatry, Bolligenstr. 111, CH-3000 Bern 60, Switzerland. thomas.koenig@puk.unibe.ch
Lehmann
D
D
Saito
N
N
Kuginuki
T
T
Kinoshita
T
T
Koukkou
M
M
D000208:Acute Disease; D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D001921:Brain / Q000503:physiopathology*; D004569:Electroencephalography; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000209:etiology; D012559:Schizophrenia / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology*; D013826:Theta Rhythm
D014150:Antipsychotic Agents