Changes of bioelectric brain activity registered at the distance from the focus of cerebral tissue injury

The focal delta-waves and the remote influences of the stroke in the form o f the sinusoidal flashes of delta-waves with a maximal amplitude exceeding an amplitude of the focal delta-waves (frontal flashes - FF) in frontal-pol ar leads were investigated in 51 patients (22 men, 29 women) by means of ma pping, dipole location (BrainLoc) and LORETA methods. The patients were exa mined in dynamics during the acute period of hemispheric stroke on days 1-3 , 14 and 21 after the onset of the disease. The usage of the modern compute r methods of EEG analysis permits to consider FF as an independent electrop hysiological phenomenon and to localize a zone of the sources of such flash es, which does not coincide with the zone of generation of the focal delta- activity that corresponds to the perifocal zone of the stroke. According to the data of the three-dimensional location a probable zone of FF generatio n corresponds to the frontal pole and medial-basal areas of the frontal lob e. Comparison with the MRI data leads to the conclusion that a damage of an terior white substance was the most frequent cause of FF development, proba bly by deafferentation mechanism. FF may be an electrophysiological manifes tation of the influence of the damage of the different brain structures on the frontal lobes according to diaschisis mechanism.