D. Lacroix et al., QUANTIFIED EEG CHANGES ASSOCIATED WITH A POSITIVE CLINICAL-RESPONSE TO CLOZAPINE IN SCHIZOPHRENIA, Progress in neuro-psychopharmacology & biological psychiatry, 19(5), 1995, pp. 861-876
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.