Quantitative EEG of elderly schizophrenic patients.

To investigate the brain function of elderly schizophrenic patients, quantitative EEGs of such patients were compared with those of healthy elderly controls. In schizophrenics, increases in delta and slow theta (4.0-6.0 Hz) waves were thought to be due to the influence of antipsychotics. Characteristic EEG features of these patients included the following: 1) more fast theta (6.0-8.0 Hz) wave was observed, with less alpha wave faster than 9.0 Hz, 2) the reduction in alpha 3 (10.0-11.0 Hz) wave was limited to the frontal regions. The present EEG findings are thought to characterize the traits of the subtype of chronic severe schizophrenia. The reduction in alpha 3 wave in the frontal regions may be one expression of the hypofrontality of schizophrenia.