[Changes of the EEG capacity observed in certain pathologies of the central nervous system and in pain].
Published data on changing spectra of electroencephalograms (EEG), as observed in different pathological hypoxic conditions (hypoxia, ischemia of the brain, aging) were analyzed; changing EEG spectra were experimentally studied in pain. The EEG changes were found to be identical in all cases. At the very beginning of a pathological factor onset, there was an increasing dominating peak of the EEG spectrum (or, the beta2-frequency range was going up--stage I). Then, the spectral distribution began to shift gradually to the low-frequency region: the frequency-predominant rhythm was slowing down; the slow-wave region was increasing and the fast-wave EEG part (II, III) was decreasing. Affections in pain fit the limits of I and II and, sometimes, III stages. In hypoxia and ischemia, a new stage of changes (IV) developed later: there emerged, in EEG, a peculiar high-amplitude rhythmic "burst-type" activity, which preconditioned a specific pattern of the EEG spectrum (the discussed stage is hard to detect in aging). The above stage is critical for the body. The total EEG capacity sharply dropped after its onset in hypoxia, ischemia and aging and the bioelectric activity was made up only of scanty slow waves (V). The described changing EEG spectra develop at an increasing total spectrum capacity (hypoxia), at capacity decrease (ischemia and aging) or it does not change altogether (pain). The homogeneous changes of EEG spectra in the above pathophysiological conditions make it possible to conclude that they denote a gradual progression of a change in brain functioning. It was suggested that such change is related with a slowing general velocity in brain functioning.
S V
SV
Krapivin
A V
AV
Kharitonov
T A
TA
Voronina
D000818:Animals; D001921:Brain / Q000503:physiopathology*; D002545:Brain Ischemia / Q000503:physiopathology*; D004569:Electroencephalography; D002534:Hypoxia, Brain / Q000503:physiopathology*; D008297:Male; D010146:Pain / Q000503:physiopathology*; D051381:Rats; D017208:Rats, Wistar