[Symmetry and stability of the EEG spectra of healthy subjects].
Stability and symmetry of power spectra and the EEG coherence function have been investigated in 40 healthy subjects with different characteristics of cerebral electrical activity. It has been shown that the power spectra in all healthy subjects are characterized by a high degree of symmetry and stability. The average levels of coherence of the symmetric points of the right and left hemisphere proved to be a reliable EEG characteristics of a healthy subject. In contradistinction, the pattern of the coherence spectrum displays considerable variability and non-stability. Subjects with a desynchronized EEG differ from those with alpha-rhythm predominance by the highest coherence and similarity of the spectra along with their low stability in the anterior parts of the hemisphere which testifies to a high dynamic integration of the frontal systems.