GLOBAL, REGIONAL, AND LOCAL MEASURES OF COMPLEXITY OF MULTICHANNEL ELECTROENCEPHALOGRAPHY IN ACUTE, NEUROLEPTIC-NAIVE, FIRST-BREAK SCHIZOPHRENICS

Background: Schizophrenic symptoms commonly are felt to indicate a loo sened coordination, i.e. a decreased connectivity of brain processes. Methods: To address this hypothesis directly, global and regional mult ichannel electroencephalographic (EEG) complexities (omega complexity and dimensional complexity)) and single channel EEG dimensional comple xities were calculated from 19-channel EEG data from 9 neuroleptic-nai ve, first-break, acute schizophrenics and 9 age- and sex-matched contr ols. Twenty artifact-free 2 second EEC epochs during resting with clos ed eyes were analyzed (2-30 Hz bandpass, average reference for global and regional complexities, local EEG gradient time series for single c hannels). Results: Anterior regional Omega-Complexity was significantl y increased in schizophrenics compared with controls (p < 0.001) and a nterior regional Dimensional Complexity showed a trend for increase. S ingle channel Dimensional Complexity of local gradient waveshapes was prominently increased in the schizophrenics at the right precentral lo cation (p = 0.003). Conclusions: The results indicate a loosened coope rativity or coordination (vice versa: an increased independence) of th e active brain processes in the anterior brain regions of the schizoph renics. (C) 1998 Society of Biological Psychiatry.