Electroencephalographic changes as prognostic indicators after psychosurgery.

Thirty-five patients were studied by EEG with recordings taken the day before, two weeks after, and six months after psychosurgery. Most showed a characteristic frontal slow activity of varying degrees after operation with varying enhancement of background activity. The amount and spread of the frontal slow waves two weeks after operation showed a significant positive correlation with the clinical outcome one year later, which suggests a relatively objective and very early indication of the subsequent clinical response to psychosurgery.