Psychomotor disturbances in psychiatric patients as a possible basis for new attempts at differential diagnosis and therapy. IV. Brain dysfunction during motor activation measured by EEG mapping.

In parts I-III of this series psychometric evidence was reported of a "psychotic motor syndrome" (PMS) in schizophrenic and endogenous depressed patients, which was not found in non-endogenous depressed or healthy persons. An attempt is reported to establish signs of brain dysfunction in these patient groups during motor activation, using a 16-channel EEG mapping system. "Resting" conditions after a special relaxation procedure were compared with simple and complex motor tasks (and music perception/reproduction; to be reported separately). Two measurements, at least 2 weeks apart, were obtained for each subject, in order to obtain information on the influence of drug treatment and/or psychopathological improvement on brain dysfunction. In all, 23 male and 25 female schizophrenics, 11 male and 18 female non-endogenous depressed patients (not actually mediated, i.e. drug naive or wash-out period of 1 week to 17 years), and 26 male and 37 female endogenous depressed patients (medicated with tri- or tetracyclic antidepressants and/or benzodiazepines; no lithium treatment) were compared with 22 male and 17 female control persons (i.e. total n = 179). Major findings were obtained in the delta and alpha frequency bands yielding signs of "diffuse hyperactivation" in schizophrenic and endogenous depressed patients as compared with the patterns found in healthy persons. However, since in the non-endogenous patients a (less marked) hyperactivation of various EEG parameters was also found, unspecific effects such as anxiety/arousal may have influenced the results in psychotic patients, which was to be explored further. Drug treatment tended to "normalize" the activation pattern both in schizophrenics and endogenous depressed patients. Viewing the findings on schizophrenics using neuroimaging methods [single photon emission computerized tomography-(SPECT), magnetic resonance imaging-(MRI), positron emission tomography-(PET)], these results suggest pathological brain organization connected to an impaired motor performance (evident peripherally as PMS) in schizophrenic and endogenous depressed patients. If it is possible to further "externally validate" (by SPECT/MRI/PET) EEG mapping data this method may exclusively offer the possibility of innocuous long-term follow up of brain dysfunction in psychotic patients ("brain function monitoring"). This could enable the early recognition (and early therapy) of negative symptoms. Finally, the EEG mapping findings provide further neurophysiological basis for the use of motor training programs in the additional therapy of psychiatric patients.