The effect of dexamethasone on electroencephalograms in patients with brain tumors with specific reference to topographic computer display of delta activity.

Nine patients with primary or metastatic brain tumors were examined with topographic computer display of delta activity before and after administration of dexamethasone. In six cases with primary malignant or metastatic brain tumors a diminution of delta distribution was observed following intravenous administration of dexamethasone, and no significant changes of the topographic map of the delta wave were obtained in two cases of benign brain tumor without clinical signs of increased intracranial pressure. Some of the changes of delta activities are believed to be correlated with the amount of peritumor edema. It is noteworthy that the change of focal delta activities by steroid was detected 20 minutes after administration.