ELECTROPHYSIOLOGICAL CHANGES IN THE PARTICIPANTS OF THE LIQUIDATION OF THE CONSEQUENCES OF THE CHORNOBYL ACCIDENT AND THE MILITARY PERSONNEL OF THE UKRAINIAN DEFENSE FORCES RECOVERING FROM CORONAVIRUS DISEASE (COVID-19).

Objective: to conduct a clinical and neurophysiological study of Chornobyl clean-up workers and military personnelof the Armed Forces of Ukraine (AFU) with previous coronavirus disease (COVID-19) and individuals of the comparison groups to study the impact of long-term effects of ionizing radiation, psychoemotional stress and previouscoronavirus infection on cerebral functioning.

Materials and methods: A prospective clinical study of Chornobyl clean-up workers and servicemen of the ArmedForces of Ukraine (AFU) who had coronavirus disease (COVID-19) and individuals of the comparison groups. Themain group - 30 males participated in liquidating the consequences of the Chornobyl Nuclear Power Plant (ChNPP)accident with previously verified COVID-19 (Chornobyl clean-up workers). As a nosological control group (NCG), 24men with verified chronic cerebrovascular disorder (CVD) not exposed to radiation sources, war-associated psychoemotional stress, and COVID-19 were examined in 2020-2022. Depending on the history of COVID-19, the AFU servicemen were divided into 2 subgroups: «COVID+» and «COVID-». The diagnosis of neuropsychiatric disorders wasestablished according to ICD-10. Visual and spectral EEG analyses assessed cerebral functions in passive wakefulness (rsEEG).

Results: Chornobyl clean-up workers «COVID+» and NCG groups did not differ significantly in clinical neuropsychiatric features, except for a higher frequency of organic personality disorder (F07) in the group of the Chornobyl cleanworkers «COVID+» (p < 0.001). In the group of the Chornobyl clean workers «COVID+» relative ( %) spectral deltapower of EEG was significantly diffusely increased as well as absolute spectral delta-power in the left posterior-temporal area compared to NCG (p < 0.05). A significant diffuse increase in relative spectral theta-power with a bilateral excess in parietal areas (p < 0.05 - 0.01), as well as a significant increase in absolute spectral theta-power bilaterally in frontal areas (p < 0.05) was found in the group AFU «COVID+», compared to the group AFU «COVID-».

Conclusions: For the first time, a pronounced diffuse slowing of cerebral bioelectrical activity to delta-frequencieswas detected in the Chornobyl clean-up workers being COVID-19 recuperates compared to the comparison groupwith chronic CVD. The AFU servicemen with previous COVID-19 have moderate persistent cerebral dysfunction. Thesechanges require further observation and study.