Research in the past years using various mathematic methods of EEG analysis has shown that the most adequate approach to the solution of contemporary problems of clinical electroencephalography is the analysis of intercentral interactions on the basis of EEG coherence calculation (Boldyreva, Sharova, Zhavoronkova, & Dobrokhotova, 1992; Boldyreva, Zhavoronkova, Sharova, & Dobronravova, 2003; Rusinov, Grindel, Boldyreva, & Vakar, 1987; Sharova, Borodkin, Gognitidze, Lukianov, & Muhanov, 1992; Sharova, Manelis, Kulikov, & Barkalaia, 1995; Sharova, Obraztsova, Zaitsev, Kulikov, & Urakov, 2001; Zhavoronkova, 2006).
Analysis of intercentral interactions of brain electrical processes in healthy subjects in a state of relative rest revealed that the average levels of coherence (Rusinov et al., 1987) of symmetrical hemisphere regions independent of EEG type (alpha activity characteristics) and individual asymmetry profiles are characterized by a significant similarity and the presence of an anterior-posterior falling gradient of biopotential association.
An important characteristic of brain electrical activity is the measurement of the stability of EEG intercentral interactions.
The analysis of changes in intercentral interactions in states of decreased vigilance (transition to somnolence) revealed the evening out of hemispheric differences in brain biopotential organization (Boldyreva & Zhavoronkova, 1989; Zhavoronkova, Boldyreva, & Dobrokhotova, 1988; Zhavoronkova & Trofimova, 1997, 1998).
The study of the dynamics of intercentral interactions with afferent stimulation showed that reactive shifts in subjects with various asymmetry profiles were multiform.
It was revealed that the disturbance of intercentral interaction is expressed more diffusely in these cases than in cases of cortical damage.