[Results of EEG mapping in brain tumors. Comparison with imaging methods]

Thirty-nine patients with brain tumors were studied with conventional and Q. EEG mapping (FFT) comparatively to CT-Scan. In 33 cases, Q. EEG provided a precise localization of the tumor site, based on slow waves. Furthermore there was a good correlation between CT-Scan and focal theta activity in 31 patients. Focal delta waves were more frequent in deep tumors involving white matter. In 11 of 13 superficial tumors, alpha rhythm was ipsilaterally located, whereas in deeper lesions, its activity was decreased on the tumor side. The putative mechanism of these results are discussed.