Kuts K. Neurocognitive deficit in chronic cerebrovascular pathology in the individuals exposed to ionizing radiation in low doses range due to the Chornobyl accident

The dissertation is devoted to solving the scientific problem of objectification and verification of the cognitive impairment in chronic cerebrovascular pathology in the remote period following the radiation exposure in low doses range due to the Chornobyl accident, which includes the detection of the dose-dependent neuropsychological and psychophysiological markers of cognitive deficit and the determination of its cerebral topographic localization after irradiation. In order to achieve the goal and to accomplish the tasks of the dissertation, the prospective clinical study of 185 male liquidators of the consequences of the accident at the Chornobyl Nuclear Power Plant at the attained age of 44-65 with verified chronic cerebrovascular pathology irradiated at the dose range of 0.0002-1.23 Sv, with both the internal (liquidators irradiated at doses up to 50 mSv) and external (25 unexposed persons with verified chronic cerebrovascular pathology and 25 practically healthy persons of the corresponding age and sex) control groups was performed. The unified neuropsychiatric examination was executed using clinical, neuro- and psychometric, neuropsychological and psychophysiological methods. The full IQ deficit at the expense of the predominant verbal IQ reduction may be considered as the neuropsychological markers of the cognitive impairments in the liquidators with chronic cerebrovascular pathology, which reflect the lateralization of the lesion to the left (dominant) brain hemisphere and become dose-dependent at doses of more than 0.3-0.5 Sv. The psychophysiological markers of cognitive impairments in the liquidators with chronic cerebrovascular pathology include the decrease in the theta range spectral power in the left fronto-temporal area, as well as both the increase in the latency and the decrease in the amplitude of the cognitive auditory evoked potentials P300 in the Wernicke's area. The new radiocerebral psychophysiological effect in the Wernicke's area in the liquidators irradiated at doses of more than 0.05 Sv has been detected. The obtained results lead to the conclusion about the presense of the radio-induced disruptions of cerebral functions in the liquidators with chronic cerebrovascular pathology, which arise following exposure to low doses of ionizing radiation. The diagnostic criteria for neurocognitive deficit in chronic cerebrovascular pathology in the remote period following radiation exposure in low doses range due to the Chornobyl accident have been developed, taking into account clinical neuropsychiatric, neuro- and psychometric, neuropsychological and psychophysiological indices. The field of application is medicine.