QUANTIFIED EEG CHANGES ASSOCIATED WITH A POSITIVE CLINICAL-RESPONSE TO CLOZAPINE IN SCHIZOPHRENIA

1- The authors conducted a retrospective exploratory computerized EEG study on the effect of clozapine in treatment-refractory schizophrenic s, 10 high-responders (HRs) and 10 low-responders (LRs), in an attempt to correlate amplitude but especially coherence changes with a positi ve clinical response to clozapine. 2- EEGs with eyes closed were obtai ned before and during a clozapine treatment. Both groups had a similar drug profile with regards to non-clozapine medication. Probability ma ps were computed to illustrate changes of amplitude and coherence (for all combinations of paired electrodes) for 4 frequency bands (theta, alpha, beta1 and 2). 3- The effect on AMPLITUDE was a generalized incr ease in lower bands and a decrease in anterior regions in higher bands of both HRs and LRs. Considerable changes of COHERENCE were observed on a wide set of paired electrodes in most frequency bands with some e lectrodes involved in HRs but uninvolved or differently involved in LR s suggesting differences in selected brain regions. 4- Changes of cohe rence but not amplitude were correlated with changes on the BPRS, thus to clinical improvement, and concerned mostly the right anterior-medi al temporal (T4) and central (C4) electrodes paired with prefrontal el ectrodes, left central (C3), temporal (T3) and parietal (P3) electrode s in the theta band. 5- Clozapine has both generalized and regional ef fects as can be suspected considering its effect on many subtypes of b rain receptors. A brain dysfunction centralized on the right anterior- medial temporal region may characterize treatment-refractory schizophr enics.