Triphasic waves and cerebral tumors.

Three patients with cerebral tumor involving diencephalic midline structures (2 malignant gliomas, 1 craniopharyngioma) and no metabolic abnormalities developed disorientation in time and place or coma with triphasic waves (TW) seen on electroencephalograms. Serial EEG recordings showed persistence or disappearance of TW depending on poor or good outcome of the antiedema treatment. TW have been described with disorders affecting the brain diffusely, as metabolic encephalopathies, dementing processes, cerebral carcinomatosis and baclofen intoxication. The findings described here demonstrate that TW may occur in patients with brain tumor involving subcortical midline structures.