The electroencephalogram in metastatic brain tumors

Abstract

Sixty cases of intracranial metastatic tumors diagnosed either clinically or by neurosurgery (28 operative cases, 26 with radiological contrast examinations and 6 with clinical diagnosis only) are reported. The EEG tests had been made previously to the diagnosis of metastasis. The EEG results are analysed according to the previous impression gained from this test and are presented in 5 tables, on which the cases are divided as per the brain topography of the metastasis. The positive EEG data are analysed and the possibility of topographic diagnosis discussed. The results agree with those presented in the literature. The AA. reach the following conclusions: 1) in patients with suspect brain metastasis the normal EEG allows with great probability to exclude the possibility; 2) in patients with malignant tumor the EEG signs of involvement of the nervous parenchyma are the most important elements for positive diagnosis of brain metastasis; 3) in the cases of metastasis developing at the posterior fossa, either there were indicative signs of the process at that level or the EEG was normal; 4) the EEG signs of an irritant process at the brain cortex were less frequent and, in the majority of cases, appeared in the temporal and parietal areas; 5) the signs of involvement of the mesodiencephalic structures in tumors of the brain hemispheres appeared only when the tumor was located in the median part of the hemisphere (temporal or parietal lobes); 6) signs of depression of the basal electric brain activity in the affected areas appeared rarely and in cases of parietal or occipital tumors; 7) the electric brain activity of other areas of the involved hemisphere or in the opposite hemisphere was normal in the majority of the cases observed. Considering the results of the literature and their own the AA. believe that the EEG could be a semiological method to be used at the preoperative examinations of patients with malignant tumors, with a view at establishing the possible existence of brain metastasis even in the absence of clinical symptoms. The evidence is obviously most important for orientation of the therapy in such cases, whether surgical or not.