Electroencephalographic Cartography

Abstract

Control subjects and neurological and psychiatric patients (n = 217 sequences recorded over both hemispheres) have been recorded. Minicomputers (HP Fourier analyzer, HP 1000) for spectral analysis provided 10 spectral parameters over 5 spectral frequency bands (.delta., .theta., .alpha., .beta.1, .beta.2, raw EEG). For each recorded sequences, 90 EEG maps could be computed over both hemispheres. Topo-EEG were stored in an EEG image data bank. An EEG mapping microcomputer system linked with a digital polygraph (Alvar Electronic, REEGA 2000) has been used simultaneously. White noises have been fed into both computers for testing spatial resolution. Ten topo-EEG have been recorded in control subjects and patients. The microcomputer system has provided very reliable topographical results when compared to similar maps generated by the minicomputer. A common average reference has been used. The 1st clinical applications have been studied (brain strokes, brain tumors). This method appears very reliable in comparison with CT [computed tomography] scans.