[The changes in electroencephalogram parameters in patients in the somatogenic phase of acute poisoning with opioid receptor agonists].

Objective: To evaluate the parameters of the electroencephalogram (EEG) using the methods of computer processing of EEG data for an approach to the analysis of possible neurophysiological mechanisms underlying the fluctuations detected in the EEG in patients in the somatogenic phase of acute poisoning with opioid receptor agonists.

Material And Methods: Thirty-one patients were examined in the somatogenic phase of acute poisoning with opioid receptor agonists with a wakefulness level 3 to 15 points on the Glasgow Coma Scale. The EEG was recorded in accordance with the recommendations of the International Federation of Clinical Neurophysiology. The indicators of electrical activity of the brain were analyzed; computer processing of EEG data, including spectral analysis, localization of equivalent dipole sources of pathological electrical activity of the brain localization of the maximum of the equivalent density of EEG oscillation currents in the neocortex, was performed.

Results: Delta-band oscillations dominated in the majority of patients (65%, 20 patients). EEG delta waves were localized mainly at the level of the thalamus; using the method of low-resolution electromagnetic tomography, the localization of the maximum of the equivalent current density of delta oscillations in the projection of the neocortex was noted. Possible neurophysiological mechanisms of «pathological» delta waves recorded in the EEG of these patients are discussed.

Conclusions: The changes on the EEG in these patients arise as a result of a disturbance of the function of the generator mechanisms of both cortical and activating structures of the brain, while the recorded slow-wave, mainly delta activity, taking into account the recording time (somatogenic phase), may be due to the action of secondary alternating factors (hypoxia and cerebral edema).