Practical use of electroencephalography

The possibility to objectively assess the state of the brain tissue on the basis of electroencephalographic surveys led to the wide use of this method not only for neurophysiological studies, but in the neuropathology and psychiatry. At the first stages of the research attempts to link the separate forms of oscillations of biopotentials ("sharp waves", gipersecretornye slow oscillations, paroxysmal activity and so on) with views of the disease. However, the accumulated material showed that the EEG reflects not a disease and its cause, and the condition of the brain tissue. Only by studying the dynamics of changes of bioelectrical activity in close relation with other indicators, it is possible to make conclusions about what is happening in the brain pathological processes and the nature of the disease. So in clinical surveys are increasingly functional tests or functional load. For this purpose use of pharmacological effect and external irritation. It is to some extent allows to make conclusions about the correlation of the excitatory and inhibitory processes in brain tissue, their mobility and inactivity.
As in various pathological processes, the decrease of the frequency of oscillations in EEG (the appearance of slow waves), this method has found wide application in neurosurgery for detection and localization of brain tumors (Fig. 5).
Due to the ability of bioelectric activity to judge the state of the brain EEG research method is widespread in many branches of science and practice.
        
Fig. 5. A tumor of the left lateral ventricle. Pathological slow waves recorded more clearly when basal radial lead (B), than in unipolar (A) (observation Novikova and Rusinova). A - electroencephalogram left hemisphere, recorded unipolar method; B - electroencephalogram same hemisphere, recorded with basal-radial lead. 1-occipital unipolar abstraction; 2 - parietal unipolar abstraction; 3 - temporal unipolar abstraction; 4 - frontal unipolar abstraction; 5 - basal-occipital abstraction; 6 - basal-parietal abstraction; 7 - basal-temporal abstraction; 8 - basal skull abstraction